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Portable ext. HDDs without power AC?

Hello.

I know some people prefer to use portable external HDDs, with their 
power AC connection enclosures or adapters, for reliability and 
stability. Some people prefer those tiny HDDs with only their USB 
connections for both power and accessing data (easiest and lightest).

Are there any external HDD adapters and enclosures that do not use power 
AC connections? I don't know mind having to use another 
USB/Firewire/ESATA/Thunderbolt cable connection to the computer when 
using one already instead of having to carry its power AC cable and 
brick. I have not seen one yet. Or is it not possible?

Thank you in advance. :)
-- 
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nice and slow like..." --Ross Perot in Saturday Night Live's Debate '92 
skit.
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0
Ant
8/24/2014 7:06:49 PM
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In article <ismdnUw6FdZUqmfOnZ2dnUVZ_rqdnZ2d@earthlink.com>, Ant
<ant@zimage.comANT> wrote:

> Hello.
> 
> I know some people prefer to use portable external HDDs, with their 
> power AC connection enclosures or adapters, for reliability and 
> stability. Some people prefer those tiny HDDs with only their USB 
> connections for both power and accessing data (easiest and lightest).
> 
> Are there any external HDD adapters and enclosures that do not use power 
> AC connections? I don't know mind having to use another 
> USB/Firewire/ESATA/Thunderbolt cable connection to the computer when 
> using one already instead of having to carry its power AC cable and 
> brick. I have not seen one yet. Or is it not possible?

just about every 2.5" enclosure can be bus-powered.
however, usb power can be unreliable.
0
nospam
8/24/2014 7:13:01 PM
On 8/24/2014 12:13 PM PT, nospam typed:
> just about every 2.5" enclosure can be bus-powered.
> however, usb power can be unreliable.

What about other connection types like ESATA, Firewire, Thunderbolt, 
etc. if they exist on the computers?
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0
Ant
8/24/2014 7:26:16 PM
In article <yNadnZiHktfKoWfOnZ2dnUVZ_uidnZ2d@earthlink.com>, Ant
<ant@zimage.comANT> wrote:

> On 8/24/2014 12:13 PM PT, nospam typed:
> > just about every 2.5" enclosure can be bus-powered.
> > however, usb power can be unreliable.
> 
> What about other connection types like ESATA, Firewire, Thunderbolt, 
> etc. if they exist on the computers?

esata doesn't provide power.
firewire provides power.
very few thunderbolt drives are bus-powered and not cheap.
0
nospam
8/24/2014 7:38:27 PM
On 8/24/2014 12:38 PM PT, nospam typed:

>>> just about every 2.5" enclosure can be bus-powered.
>>> however, usb power can be unreliable.
>>
>> What about other connection types like ESATA, Firewire, Thunderbolt,
>> etc. if they exist on the computers?
>
> esata doesn't provide power.
> firewire provides power.
> very few thunderbolt drives are bus-powered and not cheap.

Interesting. Now, do enclosures and adapters without power AC connection 
and use stable Firewire's power exist?
-- 
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blowin' in the wind." --the misheard lyrics to Bob Dylan's "Blowin' in 
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0
Ant
8/24/2014 8:00:59 PM
In article <sqadnWBDd4Dh2WfOnZ2dnUVZ_tednZ2d@earthlink.com>, Ant
<ant@zimage.comANT> wrote:

> >>> just about every 2.5" enclosure can be bus-powered.
> >>> however, usb power can be unreliable.
> >>
> >> What about other connection types like ESATA, Firewire, Thunderbolt,
> >> etc. if they exist on the computers?
> >
> > esata doesn't provide power.
> > firewire provides power.
> > very few thunderbolt drives are bus-powered and not cheap.
> 
> Interesting. Now, do enclosures and adapters without power AC connection 
> and use stable Firewire's power exist?

firewire is the most reliable since it sources the most power.

it can even run *two* laptop drives daisy-chained off of one port,
possibly even three but that's pushing it (7-8 watts available, versus
2.5w for standard usb).

older macs sourced more current and could even power 3.5" drives (which
did exist briefly) but that hasn't been the case for years.
0
nospam
8/24/2014 8:10:06 PM
On 8/24/2014 1:10 PM PT, nospam typed:

> firewire is the most reliable since it sources the most power.
>
> it can even run *two* laptop drives daisy-chained off of one port,
> possibly even three but that's pushing it (7-8 watts available, versus
> 2.5w for standard usb).
>
> older macs sourced more current and could even power 3.5" drives (which
> did exist briefly) but that hasn't been the case for years.

Aww, so it won't matter these days for the newer stuff then. I remember 
using an external DVD-ROM drive that used two USB connections that 
didn't use power AC.
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Ant
8/24/2014 8:29:36 PM
Ant wrote:
Note: I could not reply to alt.comp.periphs.hdd as that newsgroup is not
peered to my Usenet provider (Albasani).

> nospam typed:
>
>> just about every 2.5" enclosure can be bus-powered. however, usb
>> power can be unreliable.
> 
> What about other connection types like ESATA, Firewire, Thunderbolt, 
> etc. if they exist on the computers?

eSATA is just SATA with a shielded data cable running to a backpanel
connector.  Look at your SATA drives.  They have BOTH a data connection
and a power connection.  Those are separate connections.  The eSATA port
just has the data cable going to it.  The eSATA device (external drive)
must be self-powered.

  http://www.interfacebus.com/eSATA_Interface.html

Like USB, Firewire provides a power pin in its connector.  See:

  http://www.interfacebus.com/Design_Connector_Firewire.html#b

However, many of the IEEE-1394 devices (e.g., cameras) only have the
mini 4-pin connector in them.  The 6-pin computer connector has a power
pin.  The 4-pin device mini connector does not.  The Firewire device
with a mini 4-pin connector must be self-powered.

I haven't heard of a "Thunderbolt" cabling scheme, and the above site
doesn't list specs and pinouts for one.  Looks like a Mac/Apple thing:
http://macs.about.com/od/faq1/f/What-Is-Thunderbolt-High-Speed-I-O.htm.
Found the pinout at:

  http://pinoutsguide.com/SerialPorts/apple_thunderbolt_pinout.shtml

Doesn't look to be any power pins so the external device must be
self-powered.  This hardware protocol was designed to work with monitors
and transfer data, so those other devices have their own power.

Is there a reason why you don't want to use a USB-powered external HDD?
When looking at e-tailers, look for 2.5" laptop drives.  Don't get any
rated "green" or power saving.  You don't want the drive to power down
or stop spinning as it can interfere with its use, especially during
long file transfers (e.g., backups that take an hour, or more).  

Just as important is getting a good enclosure.  I had tried a Rosewill
case but it seems USB is flaky on anything Rosewill (I've had several
Rosewill products with USB and ended up returning all of them).  I got a
Vantec (http://www.newegg.com/Product/Product.aspx?Item=N82E16817392032)
and it worked very well.  The retaining screws are ridiculously tiny
(but they provide the jeweler's screwdriver) yet they held okay the
drive tray into the case.  Comes with a Y-adapter USB cable since you'll
need to use 2 USB ports to power an external drive.  Each USB port can
supply a max of .5A and most drives (within reasonable price) require
more than that on power up (to handle the surge when the drive has to
start spinning from being stopped).  This is a USB2 enclosure.  You can
find USB3 enclosures, and with USB3's higher power output you'll only
need one USB3 port.  Vantec has another that looks almost the same
(http://www.newegg.com/Product/Product.aspx?Item=N82E16817392083) but
must have a different PCB or chips inside to support USB3.

Be sure to check the max partition size when getting an external case.
The chip they use may have a limit that is smaller than the drive you
want to use as one partition; else, you have to slice up the drive into
2, or more partitions.  The Vantec USB3 mentioned above states a max
partition size of 1.5TB.  The Vantec USB2 that I got to house the old
laptop drive (when I put a bigger drive into the laptop) says it
supports up to 720GB.
0
VanguardLH
8/24/2014 8:34:18 PM
Ant <ant@zimage.comANT> wrote

> I know some people prefer to use portable external HDDs, with their power 
> AC connection enclosures or adapters, for reliability and stability.

That's mad. By definition external HDDs are less reliable than
internal drives just because they are easier to drop and knock
over and because they don’t have as good cooling as you can
easily achieve with an internal drive in a decent case.

> Some people prefer those tiny HDDs with only their USB connections for 
> both power and accessing data (easiest and lightest).

And those use laptop drives which handle shocks better.
But those hard drives are a lot more prone to people
doing stupid stuff when they are running too.

> Are there any external HDD adapters and enclosures that do not use power 
> AC connections?

Yes, the 2.5" drives are normally powered from the USB cable.

> I don't know mind having to use another USB/Firewire/ESATA/
> Thunderbolt cable connection to the computer when using one already 
> instead of having to carry its power AC cable and brick. I have not seen 
> one yet.

There are hordes of those around.

> Or is it not possible?

Yes it is possible. The smaller external drives are done that way.
 

0
Rod
8/24/2014 8:43:31 PM
In article <H8SdnfSgK6mt1mfOnZ2dnUVZ_oqdnZ2d@earthlink.com>, Ant
<ant@zimage.comANT> wrote:

> Aww, so it won't matter these days for the newer stuff then. I remember 
> using an external DVD-ROM drive that used two USB connections that 
> didn't use power AC.

that's a gross hack.
0
nospam
8/24/2014 8:44:05 PM
In article <ltdi8b$6kv$1@news.albasani.net>, VanguardLH <V@nguard.LH>
wrote:

> However, many of the IEEE-1394 devices (e.g., cameras) only have the
> mini 4-pin connector in them.  The 6-pin computer connector has a power
> pin.  The 4-pin device mini connector does not.  The Firewire device
> with a mini 4-pin connector must be self-powered.

macs have never had 4 pin firewire ports so that's not an issue.

you're also neglecting the 9 pin firewire 800 plug which also has power.

> I haven't heard of a "Thunderbolt" cabling scheme, and the above site
> doesn't list specs and pinouts for one.  Looks like a Mac/Apple thing:
> http://macs.about.com/od/faq1/f/What-Is-Thunderbolt-High-Speed-I-O.htm.
> Found the pinout at:
> 
>   http://pinoutsguide.com/SerialPorts/apple_thunderbolt_pinout.shtml
> 
> Doesn't look to be any power pins so the external device must be
> self-powered.  This hardware protocol was designed to work with monitors
> and transfer data, so those other devices have their own power.

look again. what do you think pin 20 is?

<http://www.barefeats.com/hard188.html>
  ROUND-UP: Bus-Powered Thunderbolt Storage Devices

<http://www.buffalotech.com/products/portable-hard-drives/portable-hard-
drives/ministation-thunderbolt>
  PORTABLE BUS-POWERED THUNDERBOLT DRIVE / USB 3.0 STORAGE

<http://www.digitaltrends.com/computing/western-digital-casts-down-my-pa
ssport-pro-the-first-thunderbolt-powered-portable-dual-external-hard-dri
ve/>
  Western Digital, one of the computing industry�s big storage makers, 
  just announced a new line of My Passport Pro portable hard drives.
  What makes these stand out is the fact the company claims they�re the
  first portable Thunderbolt bus-powered dual disk external drives.
0
nospam
8/24/2014 8:44:06 PM
Ant <ant@zimage.comANT> wrote 
> nospam wrote

>> just about every 2.5" enclosure can be bus-powered.
>> however, usb power can be unreliable.
 
> What about other connection types like ESATA, Firewire, 
> Thunderbolt, etc. if they exist on the computers?

You don't see many drives like that anymore now that
USB3 means that they don't have any speed advantage. 
 
0
Rod
8/24/2014 8:45:04 PM
Ant <ant@zimage.comANT> wrote
> nospam wrote

>>>> just about every 2.5" enclosure can be bus-powered.
>>>> however, usb power can be unreliable.

>>> What about other connection types like ESATA, Firewire, Thunderbolt, 
>>> etc. if they exist on the computers?

>> esata doesn't provide power.
>> firewire provides power.
>> very few thunderbolt drives are bus-powered and not cheap.

> Interesting. Now, do enclosures and adapters without power AC connection 
> and use stable Firewire's power exist?

They are pretty rare now if they do because firewire has passed its useby 
date.

USB3 power is fine. 

0
Rod
8/24/2014 8:46:59 PM
In article <c5v15oFuf0dU1@mid.individual.net>, Rod Speed
<rod.speed.aaa@gmail.com> wrote:

> > I know some people prefer to use portable external HDDs, with their power 
> > AC connection enclosures or adapters, for reliability and stability.
> 
> That's mad. By definition external HDDs are less reliable than
> internal drives just because they are easier to drop and knock
> over and because they don�t have as good cooling as you can
> easily achieve with an internal drive in a decent case.

don't drop them and they're just as reliable.
0
nospam
8/24/2014 9:15:38 PM
nospam <nospam@nospam.invalid> wrote 
> Ant <ant@zimage.comANT> wrote
 
>> I remember using an external DVD-ROM drive that 
>> used two USB connections that didn't use power AC.
 
> that's a gross hack.

Its no different to using an external wall 
wart, much more convenient to use.  
0
Rod
8/24/2014 9:40:30 PM
nospam <nospam@nospam.invalid> wrote
> Rod Speed <rod.speed.aaa@gmail.com> wrote

>>> I know some people prefer to use portable external HDDs, with their
>>> power AC connection enclosures or adapters, for reliability and 
>>> stability.

>> That's mad. By definition external HDDs are less reliable than
>> internal drives just because they are easier to drop and knock
>> over and because they don�t have as good cooling as you can
>> easily achieve with an internal drive in a decent case.

> don't drop them and they're just as reliable.

No, because they are MUCH easier to bump when using them.

And they arent anything like as well cooled either. 

0
Rod
8/24/2014 9:42:40 PM
On 8/24/2014 1:44 PM PT, nospam typed:

>> Aww, so it won't matter these days for the newer stuff then. I remember
>> using an external DVD-ROM drive that used two USB connections that
>> didn't use power AC.
>
> that's a gross hack.

It is? Why is it bad? It worked when I used it at work.
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Ant
8/24/2014 9:58:31 PM
On 8/24/2014 2:40 PM PT, Rod Speed typed:

>>> I remember using an external DVD-ROM drive that used two USB
>>> connections that didn't use power AC.
>
>> that's a gross hack.
>
> Its no different to using an external wall wart, much more convenient to
> use.

Ditto. No annoying heavy brick to carry around!
-- 
"Ants! Why don't we all line up like a [bleeped] bunch of ants! It's the 
most beautiful part of the day!" --Robert Eroica Dupea in Five Easy 
Pieces movie
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0
Ant
8/24/2014 9:58:58 PM
["Followup-To:" header set to comp.sys.mac.hardware.storage.]
On 2014-08-24, Ant <ant@zimage.comANT> wrote:
> Hello.
>
> I know some people prefer to use portable external HDDs, with their 
> power AC connection enclosures or adapters, for reliability and 
> stability. Some people prefer those tiny HDDs with only their USB 
> connections for both power and accessing data (easiest and lightest).
>
> Are there any external HDD adapters and enclosures that do not use power 
> AC connections? I don't know mind having to use another 
> USB/Firewire/ESATA/Thunderbolt cable connection to the computer when 
> using one already instead of having to carry its power AC cable and 
> brick. I have not seen one yet. Or is it not possible?
>
> Thank you in advance. :)

As nospam indicated, since the Firewire spec provides more power than
USB, the risk of a hard drive requiring more power than the bus provides
is less with Firewire-attached drives. I've used USB bus-powered drive
enclosures before that did not supply enough power to spin up some hard
drives that had higher power requirements than USB bus provides. On the
other hand, I've used (and continue to use) Firewire bus-powered drive
enclosures with no such issues, regardless of what type of hard drive I
put inside the enclosures. IME Firewire is relatively worry-free when it
comes to powering external hard drives.

There are plenty of drive enclosures out there that support bus power
over Firewire. Here's an example of a 2.5 inch (laptop) drive enclosure
that derives power from the USB or Firewire bus to which it is
connected:

<https://eshop.macsales.com/shop/firewire/on-the-go>

I've used a couple of these for years now, with Firewire 800 connections
rather than AC connections for bus power, and they seem to be pretty
solid and reliable drive enclosures. 

-- 
E-mail sent to this address may be devoured by my ravenous SPAM filter.
I often ignore posts from Google. Use a real news client instead.

JR
0
Jolly
8/24/2014 9:59:16 PM
In article <c5v4gkFkk5U1@mid.individual.net>, Rod Speed
<rod.speed.aaa@gmail.com> wrote:

> >> I remember using an external DVD-ROM drive that 
> >> used two USB connections that didn't use power AC.
>  
> > that's a gross hack.
> 
> Its no different to using an external wall 
> wart, much more convenient to use.  

it's completely different.

nobody would think of plugging an appliance into two outlets to get 30
amps instead of 15.
0
nospam
8/24/2014 10:00:18 PM
In article <c5v4kmFla5U1@mid.individual.net>, Rod Speed
<rod.speed.aaa@gmail.com> wrote:

> >>> I know some people prefer to use portable external HDDs, with their
> >>> power AC connection enclosures or adapters, for reliability and 
> >>> stability.
> 
> >> That's mad. By definition external HDDs are less reliable than
> >> internal drives just because they are easier to drop and knock
> >> over and because they don�t have as good cooling as you can
> >> easily achieve with an internal drive in a decent case.
> 
> > don't drop them and they're just as reliable.
> 
> No, because they are MUCH easier to bump when using them.

only for klutzes.

> And they arent anything like as well cooled either. 

heat is not a significant issue.

plus, the inside of a computer is not always cooled all that well
either, and there's other components generating heat.
0
nospam
8/24/2014 10:00:25 PM
In article <isidnfIPjdub_WfOnZ2dnUVZ_s-dnZ2d@earthlink.com>, Ant
<ant@zimage.comANT> wrote:

> >> Aww, so it won't matter these days for the newer stuff then. I remember
> >> using an external DVD-ROM drive that used two USB connections that
> >> didn't use power AC.
> >
> > that's a gross hack.
> 
> It is? Why is it bad? It worked when I used it at work.

because it was never designed to do that. you're connecting two power
sources together.
0
nospam
8/24/2014 10:00:29 PM
On 8/24/2014 2:59 PM PT, Jolly Roger typed:
> There are plenty of drive enclosures out there that support bus power
> over Firewire. Here's an example of a 2.5 inch (laptop) drive enclosure
> that derives power from the USB or Firewire bus to which it is
> connected:
>
> <https://eshop.macsales.com/shop/firewire/on-the-go>
>
> I've used a couple of these for years now, with Firewire 800 connections
> rather than AC connections for bus power, and they seem to be pretty
> solid and reliable drive enclosures.

Nice transparency case. Question: Will this still work well with older 
machines that don't have USB3 ports and using USB2 ports?
-- 
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Ant
8/24/2014 10:03:29 PM
On 8/24/2014 3:00 PM PT, nospam typed:

>>>> Aww, so it won't matter these days for the newer stuff then. I remember
>>>> using an external DVD-ROM drive that used two USB connections that
>>>> didn't use power AC.
>>>
>>> that's a gross hack.
>>
>> It is? Why is it bad? It worked when I used it at work.
>
> because it was never designed to do that. you're connecting two power
> sources together.

Oh. Heh. Well, it worked for me for simple disc readings. :)
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Ant
8/24/2014 10:04:08 PM
In article <rfednZl1rbis_GfOnZ2dnUVZ_qadnZ2d@earthlink.com>, Ant
<ant@zimage.comANT> wrote:

> Nice transparency case. Question: Will this still work well with older 
> machines that don't have USB3 ports and using USB2 ports?

a usb 3 drive plugged into a computer with usb 2 ports will run at usb
2 speeds.
0
nospam
8/24/2014 10:15:32 PM
On 8/24/2014 12:13 PM, nospam wrote:


> just about every 2.5" enclosure can be bus-powered.
> however, usb power can be unreliable.

USB 3.0 ports are supposed to have alot of power.

-- 
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0
Ed
8/24/2014 10:20:33 PM
nospam <nospam@nospam.invalid> wrote 
> Rod Speed <rod.speed.aaa@gmail.com> wrote
 
>>>> I remember using an external DVD-ROM drive that 
>>>> used two USB connections that didn't use power AC.
  
>>> that's a gross hack.
 
>> Its no different to using an external wall 
>> wart, much more convenient to use.  
 
> it's completely different.

Bullshit. 
 
> nobody would think of plugging an appliance 
> into two outlets to get 30 amps instead of 15.

USB is different, stupid.  
0
Rod
8/24/2014 10:29:40 PM
nospam <nospam@nospam.invalid> wrote
> Rod Speed <rod.speed.aaa@gmail.com> wrote

>>>>> I know some people prefer to use portable external
>>>>> HDDs, with their power AC connection enclosures
>>>>> or adapters, for reliability and stability.

>>>> That's mad. By definition external HDDs are less reliable than
>>>> internal drives just because they are easier to drop and knock
>>>> over and because they don�t have as good cooling as you can
>>>> easily achieve with an internal drive in a decent case.

>>> don't drop them and they're just as reliable.

>> No, because they are MUCH easier to bump when using them.

> only for klutzes.

Bullshit. There are plenty who arent klutzes that don't
even realise that there is a spinning disk in an external
hard drive with the heads flying over the surface and
gyroscopic effects.

>> And they arent anything like as well cooled either.

> heat is not a significant issue.

Bullshit with 3.5" drives.

> plus, the inside of a computer is not
> always cooled all that well either,

Always better than with an external drive.

> and there's other components generating heat.

Irrelevant to the airflow over the drive. 

0
Rod
8/24/2014 10:32:43 PM
nospam <nospam@nospam.invalid> wrote 
> Ant <ant@zimage.comANT> wrote

>>>> Aww, so it won't matter these days for the newer stuff 
>>>> then. I remember using an external DVD-ROM drive 
>>>> that used two USB connections that didn't use power AC.

>>> that's a gross hack.
 
>> It is? Why is it bad? It worked when I used it at work.
 
> because it was never designed to do that. 

Bullshit. 

> you're connecting two power sources together.

More drivel. You are actually doing no different to
having a pair of conductors so you get half the drop.  
0
Rod
8/24/2014 10:34:46 PM
Okay, so one time? In band camp? Ed Light <nobody@nobody.there> was all, like: 
 --> 	 Sun, 24 Aug 2014 15:20:33 -0700 <53fa6537$0$46032$c3e8da3$88b277c5@news.astraweb.com>
> On 8/24/2014 12:13 PM, nospam wrote:


>> just about every 2.5" enclosure can be bus-powered.
>> however, usb power can be unreliable.

> USB 3.0 ports are supposed to have alot of power.

USB 3.0 ports have exactly the same power as USB 2.0 ports.


-- 
but then a lot of nice things turn bad out there
0
Lewis
8/24/2014 10:46:40 PM
On 2014-08-24, Ant <ant@zimage.comANT> wrote:
> On 8/24/2014 2:59 PM PT, Jolly Roger typed:
>> There are plenty of drive enclosures out there that support bus power
>> over Firewire. Here's an example of a 2.5 inch (laptop) drive enclosure
>> that derives power from the USB or Firewire bus to which it is
>> connected:
>>
>> <https://eshop.macsales.com/shop/firewire/on-the-go>
>>
>> I've used a couple of these for years now, with Firewire 800 connections
>> rather than AC connections for bus power, and they seem to be pretty
>> solid and reliable drive enclosures.
>
> Nice transparency case. Question: Will this still work well with older 
> machines that don't have USB3 ports and using USB2 ports?

USB3 is backward compatible with USB2; so yes. But Firewire 800 is
better and faster than USB2, and this drive comes with both USB and
Firewire cables. So if the computer in question has a Firewire 800 port,
I wouldn't bother with USB at all.

-- 
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JR
0
Jolly
8/24/2014 10:50:52 PM
["Followup-To:" header set to comp.sys.mac.hardware.storage.]
On 2014-08-24, Ed Light <nobody@nobody.there> wrote:
> On 8/24/2014 12:13 PM, nospam wrote:
>
>> just about every 2.5" enclosure can be bus-powered.
>> however, usb power can be unreliable.
>
> USB 3.0 ports are supposed to have alot of power.

Not enough to power some hard drives, which is why some USB enclosures
come with dual USB cables to connect to more than one USB port for
proper operation. Firewire, on the other hand, provides ample bus power
for most any hard drive you can throw at it. I have *never* seen a hard
drive enclosure that required more than one single Firewire connection
for proper operation. 

-- 
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JR
0
Jolly
8/24/2014 10:54:15 PM
In article <c5v7ihF18ckU1@mid.individual.net>, Rod Speed
<rod.speed.aaa@gmail.com> wrote:

> >> And they arent anything like as well cooled either.
> 
> > heat is not a significant issue.
> 
> Bullshit with 3.5" drives.

google's study of over 100,000 drives says otherwise.
0
nospam
8/24/2014 11:05:18 PM
In article <slrnlvkqqg.29vt.g.kreme@amelia.local>, Lewis
<g.kreme@gmail.com.dontsendmecopies> wrote:

> >> just about every 2.5" enclosure can be bus-powered.
> >> however, usb power can be unreliable.
> 
> > USB 3.0 ports are supposed to have alot of power.
> 
> USB 3.0 ports have exactly the same power as USB 2.0 ports.

wrong.

<http://arstechnica.com/gadgets/2011/08/usb-ports-that-power-laptops-mon
itors-soon-to-be-a-reality/>
  The next USB 3.0 specification will provide up to 100 watts of power
  to devices, allowing users to power some of the more demanding
  gadgets on their desks without additional power supplies. The USB 3.0
  Promoter Group announced that the standard would allow USB 3.0 ports
  to power and charge devices like notebook PCs and would remain
  backwards compatible with USB 2.0 devices.

  USB 3.0 ports introduced high data transfer speeds of up to 5Gb/s to
  compatible components, and have also been able to maintain currents
  and voltages up to 900mA at 5V for a maximum power output of 4.5W.
  This was about twice the maximum power output of USB 2.0 ports, but a
  current USB 3.0 port would still struggle to power most external hard
  drives.

however, some usb 2 ports can go beyond their spec because more power
is needed by devices, up to about 1 amp.
0
nospam
8/24/2014 11:05:20 PM
In article <c5v8onF1d7jU2@mid.individual.net>, Jolly Roger
<jollyroger@pobox.com> wrote:

> >> just about every 2.5" enclosure can be bus-powered.
> >> however, usb power can be unreliable.
> >
> > USB 3.0 ports are supposed to have alot of power.
> 
> Not enough to power some hard drives, which is why some USB enclosures
> come with dual USB cables to connect to more than one USB port for
> proper operation. Firewire, on the other hand, provides ample bus power
> for most any hard drive you can throw at it. I have *never* seen a hard
> drive enclosure that required more than one single Firewire connection
> for proper operation.

usb 3 has more power than a typical usb 2 port and can power just about
all usb drives. 

recent computers have higher power usb 2 ports so either way, it's not
really an issue anymore.
0
nospam
8/24/2014 11:05:22 PM
On 2014-08-24, nospam <nospam@nospam.invalid> wrote:
> In article <c5v8onF1d7jU2@mid.individual.net>, Jolly Roger
><jollyroger@pobox.com> wrote:
>
>> >> just about every 2.5" enclosure can be bus-powered.
>> >> however, usb power can be unreliable.
>> >
>> > USB 3.0 ports are supposed to have alot of power.
>> 
>> Not enough to power some hard drives, which is why some USB enclosures
>> come with dual USB cables to connect to more than one USB port for
>> proper operation. Firewire, on the other hand, provides ample bus power
>> for most any hard drive you can throw at it. I have *never* seen a hard
>> drive enclosure that required more than one single Firewire connection
>> for proper operation.
>
> usb 3 has more power than a typical usb 2 port and can power just about
> all usb drives. 
>
> recent computers have higher power usb 2 ports so either way, it's not
> really an issue anymore.

That's all well and good, but I'll stick with Firewire or Thuderbolt
just the same - power being just one of several reasons.

-- 
E-mail sent to this address may be devoured by my ravenous SPAM filter.
I often ignore posts from Google. Use a real news client instead.

JR
0
Jolly
8/24/2014 11:20:40 PM

"Lewis" <g.kreme@gmail.com.dontsendmecopies> wrote in message 
news:slrnlvkqqg.29vt.g.kreme@amelia.local...
> Okay, so one time? In band camp? Ed Light <nobody@nobody.there> was all, 
> like:
> --> Sun, 24 Aug 2014 15:20:33 -0700 
> <53fa6537$0$46032$c3e8da3$88b277c5@news.astraweb.com>
>> On 8/24/2014 12:13 PM, nospam wrote:
>
>
>>> just about every 2.5" enclosure can be bus-powered.
>>> however, usb power can be unreliable.
>
>> USB 3.0 ports are supposed to have alot of power.
>
> USB 3.0 ports have exactly the same power as USB 2.0 ports.

Wrong
http://en.wikipedia.org/wiki/USB#Power
 

0
whacker
8/24/2014 11:54:10 PM
nospam <nospam@nospam.invalid> wrote 
> Rod Speed <rod.speed.aaa@gmail.com> wrote

>>>> And they arent anything like as well cooled either.
 
>>> heat is not a significant issue.
 
>> Bullshit with 3.5" drives.
 
> google's study of over 100,000 drives says otherwise.

Bullshit it does. That wasn't with external drives.  
0
Rod
8/24/2014 11:55:36 PM
In article <c5vcduF257pU1@mid.individual.net>, Rod Speed
<rod.speed.aaa@gmail.com> wrote:

> >>>> And they arent anything like as well cooled either.
>  
> >>> heat is not a significant issue.
>  
> >> Bullshit with 3.5" drives.
>  
> > google's study of over 100,000 drives says otherwise.
> 
> Bullshit it does. That wasn't with external drives.  

external/internal doesn't matter.

this is about temperature, not mounting location.

google tracked drive temperature and its effect, and found that it
didn't make much of a difference, and actually failures were more
likely at lower temperatures than not.

<https://static.googleusercontent.com/external_content/untrusted_dlcp/re
search.google.com/en/us/archive/disk_failures.pdf>

  3.4 Temperature
  ...
  We first look at the correlation between average temperature during
  the observation period and failure. Figure 4 shows the distribution
  of drives with average temperature in increments of one degree and
  the corresponding annualized failure rates. The figure shows that
  failures do not increase when the average temperature increases. In
  fact, there is a clear trend showing that lower temperatures are
  associated with higher failure rates. Only at very high temperatures
  is there a slight reversal of this trend.
0
nospam
8/25/2014 12:30:53 AM
In article <240820141800182301%nospam@nospam.invalid>,
 nospam <nospam@nospam.invalid> wrote:

> In article <c5v4gkFkk5U1@mid.individual.net>, Rod Speed
> <rod.speed.aaa@gmail.com> wrote:
> 
> > >> I remember using an external DVD-ROM drive that 
> > >> used two USB connections that didn't use power AC.
> >  
> > > that's a gross hack.
> > 
> > Its no different to using an external wall 
> > wart, much more convenient to use.  
> 
> it's completely different.
> 
> nobody would think of plugging an appliance into two outlets to get 30
> amps instead of 15.

Been there,done that; worked fine.

Isaac
0
isw
8/25/2014 1:01:01 AM
nospam <nospam@nospam.invalid> wrote
> Rod Speed <rod.speed.aaa@gmail.com> wrote

>>>>>> And they arent anything like as well cooled either.

>>>>> heat is not a significant issue.

>>>> Bullshit with 3.5" drives.

>>> google's study of over 100,000 drives says otherwise.

>> Bullshit it does. That wasn't with external drives.

> external/internal doesn't matter.

Bullshit.

> this is about temperature, not mounting location.

And external drives get a LOT hotter in the worst cases.

> google tracked drive temperature and its effect,
> and found that it didn't make much of a difference,

But never tested any drives at anything like the
temps that they get to in the worst external cases.

> and actually failures were more likely
> at lower temperatures than not.

They didn't find that either.

> <https://static.googleusercontent.com/external_content/untrusted_dlcp/re
> search.google.com/en/us/archive/disk_failures.pdf>

>  3.4 Temperature
>  ...
>  We first look at the correlation between average temperature during
>  the observation period and failure. Figure 4 shows the distribution
>  of drives with average temperature in increments of one degree and
>  the corresponding annualized failure rates. The figure shows that
>  failures do not increase when the average temperature increases.

But they never tested at the temperatures seen in the worst external cases.

>  In fact, there is a clear trend showing that lower
>  temperatures are associated with higher failure rates.
>  Only at very high temperatures  is there a slight
> reversal of this trend.

That is a lie with Fig 5

 

0
Rod
8/25/2014 1:24:40 AM
In article <c5v7ihF18ckU1@mid.individual.net>,
 "Rod Speed" <rod.speed.aaa@gmail.com> wrote:

> nospam <nospam@nospam.invalid> wrote
> > Rod Speed <rod.speed.aaa@gmail.com> wrote
> 
> >>>>> I know some people prefer to use portable external
> >>>>> HDDs, with their power AC connection enclosures
> >>>>> or adapters, for reliability and stability.
> 
> >>>> That's mad. By definition external HDDs are less reliable than
> >>>> internal drives just because they are easier to drop and knock
> >>>> over and because they don�t have as good cooling as you can
> >>>> easily achieve with an internal drive in a decent case.
> 
> >>> don't drop them and they're just as reliable.
> 
> >> No, because they are MUCH easier to bump when using them.
> 
> > only for klutzes.
> 
> Bullshit. There are plenty who arent klutzes that don't
> even realise that there is a spinning disk in an external
> hard drive with the heads flying over the surface and
> gyroscopic effects.

Although you can feel the gyro effect if you tilt the drive while it's 
spinning, what is the effect *inside it* that can cause a problem?

Isaac
0
isw
8/25/2014 4:45:40 AM
In article <c5v7cqF17bvU1@mid.individual.net>,
 "Rod Speed" <rod.speed.aaa@gmail.com> wrote:

> nospam <nospam@nospam.invalid> wrote 
> > Rod Speed <rod.speed.aaa@gmail.com> wrote
>  
> >>>> I remember using an external DVD-ROM drive that 
> >>>> used two USB connections that didn't use power AC.
>   
> >>> that's a gross hack.
>  
> >> Its no different to using an external wall 
> >> wart, much more convenient to use.  
>  
> > it's completely different.
> 
> Bullshit. 
>  
> > nobody would think of plugging an appliance 
> > into two outlets to get 30 amps instead of 15.
> 
> USB is different, stupid.  

Actually, no. Using a pair of USB ports *on the same device* is a 
perfectly legitimate way to get more current than one port will deliver.

Currents just add.

Isaac
0
isw
8/25/2014 4:53:53 AM
On 8/24/2014 3:54 PM PT, Jolly Roger typed:

> Not enough to power some hard drives, which is why some USB enclosures
> come with dual USB cables to connect to more than one USB port for
> proper operation. Firewire, on the other hand, provides ample bus power
> for most any hard drive you can throw at it. I have *never* seen a hard
> drive enclosure that required more than one single Firewire connection
> for proper operation.

Which USB enclosures that have dual USB cables? I have not see any. 
Also, it would be nice if they had other cable types too.
-- 
"I once heard the survivors of a colony of ants that had been partially 
obliterated by a cow's foot seriously debating the intention of the gods 
towards their civilization" --Archy the Cockroach from Don Marquis' 
"Archy and Mehitabel" book ("Certain Maxims of Archy" poem)
    /\___/\         Ant(Dude) @ http://antfarm.ma.cx (Personal Web Site)
   / /\ /\ \                Ant's Quality Foraged Links: http://aqfl.net
  | |o   o| |
     \ _ /        If crediting, then use Ant nickname and AQFL URL/link.
      ( )         If e-mailing, then axe ANT from its address if needed.
Ant is currently not listening to any songs on this computer.
0
Ant
8/25/2014 5:45:26 AM
On 8/24/2014 3:15 PM PT, nospam typed:

>> Nice transparency case. Question: Will this still work well with older
>> machines that don't have USB3 ports and using USB2 ports?
>
> a usb 3 drive plugged into a computer with usb 2 ports will run at usb
> 2 speeds.

I meant the power part. :)
-- 
"The tiny ant dares to enter the lion's ear." --Armenian
    /\___/\         Ant(Dude) @ http://antfarm.ma.cx (Personal Web Site)
   / /\ /\ \                Ant's Quality Foraged Links: http://aqfl.net
  | |o   o| |
     \ _ /        If crediting, then use Ant nickname and AQFL URL/link.
      ( )         If e-mailing, then axe ANT from its address if needed.
Ant is currently not listening to any songs on this computer.
0
Ant
8/25/2014 5:47:59 AM
On 8/24/2014 3:50 PM PT, Jolly Roger typed:
>> Nice transparency case. Question: Will this still work well with older
>> machines that don't have USB3 ports and using USB2 ports?
>
> USB3 is backward compatible with USB2; so yes. But Firewire 800 is
> better and faster than USB2, and this drive comes with both USB and
> Firewire cables. So if the computer in question has a Firewire 800 port,
> I wouldn't bother with USB at all.

Thanks. I meant the power part. ;)
-- 
"Oh, look what Kyle got me, it's a red Mega... Ants in the pants? Ants 
in the pants?! Ants in the Pants?!! ..." --Eric Cartman in South Park's 
Damien Episode (Season 1; Episode 8)
    /\___/\         Ant(Dude) @ http://antfarm.ma.cx (Personal Web Site)
   / /\ /\ \                Ant's Quality Foraged Links: http://aqfl.net
  | |o   o| |
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      ( )         If e-mailing, then axe ANT from its address if needed.
Ant is currently not listening to any songs on this computer.
0
Ant
8/25/2014 5:48:39 AM
In article <w6idnV5y3KXrUGfOnZ2dnUVZ_rSdnZ2d@earthlink.com>, Ant
<ant@zimage.comANT> wrote:

> > Not enough to power some hard drives, which is why some USB enclosures
> > come with dual USB cables to connect to more than one USB port for
> > proper operation. Firewire, on the other hand, provides ample bus power
> > for most any hard drive you can throw at it. I have *never* seen a hard
> > drive enclosure that required more than one single Firewire connection
> > for proper operation.
> 
> Which USB enclosures that have dual USB cables? I have not see any. 
> Also, it would be nice if they had other cable types too.

it's not as common now since most computers can source more than 500ma
on one port so it's not needed as much.

most have a +5v jack (although the cheapest ones often don't).

some have firewire.
0
nospam
8/25/2014 5:49:43 AM
In article <w6idnVly3KWSU2fOnZ2dnUVZ_rSdnZ2d@earthlink.com>, Ant
<ant@zimage.comANT> wrote:

> >> Nice transparency case. Question: Will this still work well with older
> >> machines that don't have USB3 ports and using USB2 ports?
> >
> > a usb 3 drive plugged into a computer with usb 2 ports will run at usb
> > 2 speeds.
> 
> I meant the power part. :)

the power works too. it will negotiate up to whatever the port can
source.
0
nospam
8/25/2014 5:51:06 AM
nospam wrote:

> VanguardLH wrote:
> 
>> However, many of the IEEE-1394 devices (e.g., cameras) only have the
>> mini 4-pin connector in them.  The 6-pin computer connector has a power
>> pin.  The 4-pin device mini connector does not.  The Firewire device
>> with a mini 4-pin connector must be self-powered.
> 
> macs have never had 4 pin firewire ports so that's not an issue.

The PCs that I've built also had 6-pin Firewire ports.  It's the
*device* end that may not have power because many have a 4-pin port.

The OP never mention what computer(s) he has or will have access to when
and if he travels with the external drive.  Notice the mix of newsgroups
to which the OP cross-posted.

>> Thunderbolt pinout at:
>>   http://pinoutsguide.com/SerialPorts/apple_thunderbolt_pinout.shtml
>> Doesn't look to be any power pins ...

> look again. what do you think pin 20 is?

I must have not scrolled down the page to see that pin at the bottom of
the pic.  So the OP could also get an external port-powered HDD that has
the Thunderbolt port that includes power.  Or he could get one that has
USB3.  Or one that has both.
0
VanguardLH
8/25/2014 6:16:42 AM
In article <ltekcb$st3$1@news.albasani.net>, VanguardLH <V@nguard.LH>
wrote:

> >> However, many of the IEEE-1394 devices (e.g., cameras) only have the
> >> mini 4-pin connector in them.  The 6-pin computer connector has a power
> >> pin.  The 4-pin device mini connector does not.  The Firewire device
> >> with a mini 4-pin connector must be self-powered.
> > 
> > macs have never had 4 pin firewire ports so that's not an issue.
> 
> The PCs that I've built also had 6-pin Firewire ports.  It's the
> *device* end that may not have power because many have a 4-pin port.

actually very few do. i've only seen 4 pin ports on cameras and also
some crappy pcs.

have you ever seen a hard drive with a 4 pin firewire port? i sure
haven't. what would be the point in that? 

every firewire hard drive i've seen (and that's a lot because until
recently that's all i used) is a 6 or 9 pin port.

> The OP never mention what computer(s) he has or will have access to when
> and if he travels with the external drive.  Notice the mix of newsgroups
> to which the OP cross-posted.

many enclosures have multiple ports.
firewire & usb was a common combination. 
some had that awful esata/usb combo plug.
0
nospam
8/25/2014 6:28:58 AM

"isw" <isw@witzend.com> wrote in message 
news:isw-20962A.21454024082014@[216.168.3.50]...
> In article <c5v7ihF18ckU1@mid.individual.net>,
> "Rod Speed" <rod.speed.aaa@gmail.com> wrote:
>
>> nospam <nospam@nospam.invalid> wrote
>> > Rod Speed <rod.speed.aaa@gmail.com> wrote
>>
>> >>>>> I know some people prefer to use portable external
>> >>>>> HDDs, with their power AC connection enclosures
>> >>>>> or adapters, for reliability and stability.
>>
>> >>>> That's mad. By definition external HDDs are less reliable than
>> >>>> internal drives just because they are easier to drop and knock
>> >>>> over and because they don�t have as good cooling as you can
>> >>>> easily achieve with an internal drive in a decent case.
>>
>> >>> don't drop them and they're just as reliable.
>>
>> >> No, because they are MUCH easier to bump when using them.
>>
>> > only for klutzes.
>>
>> Bullshit. There are plenty who arent klutzes that don't
>> even realise that there is a spinning disk in an external
>> hard drive with the heads flying over the surface and
>> gyroscopic effects.
>
> Although you can feel the gyro effect if you tilt the drive while it's
> spinning, what is the effect *inside it* that can cause a problem?

You can end up with a head crash. 

0
Rod
8/25/2014 10:45:15 AM

"isw" <isw@witzend.com> wrote in message 
news:isw-81341E.21535324082014@[216.168.3.50]...
> In article <c5v7cqF17bvU1@mid.individual.net>,
> "Rod Speed" <rod.speed.aaa@gmail.com> wrote:
>
>> nospam <nospam@nospam.invalid> wrote
>> > Rod Speed <rod.speed.aaa@gmail.com> wrote
>>
>> >>>> I remember using an external DVD-ROM drive that
>> >>>> used two USB connections that didn't use power AC.
>>
>> >>> that's a gross hack.
>>
>> >> Its no different to using an external wall
>> >> wart, much more convenient to use.
>>
>> > it's completely different.
>>
>> Bullshit.
>>
>> > nobody would think of plugging an appliance
>> > into two outlets to get 30 amps instead of 15.
>>
>> USB is different, stupid.

> Actually, no.

Fraid so.

> Using a pair of USB ports *on the same device* is a perfectly
> legitimate way to get more current than one port will deliver.

Sure, but is nothing like plugging an appliance
into two outlets to geet 30 amps instead of 15.

> Currents just add.

Fraid not. 

0
Rod
8/25/2014 10:47:06 AM
On 2014-08-25, Ant <ant@zimage.comANT> wrote:
> On 8/24/2014 3:54 PM PT, Jolly Roger typed:
>
>> Not enough to power some hard drives, which is why some USB enclosures
>> come with dual USB cables to connect to more than one USB port for
>> proper operation. Firewire, on the other hand, provides ample bus power
>> for most any hard drive you can throw at it. I have *never* seen a hard
>> drive enclosure that required more than one single Firewire connection
>> for proper operation.
>
> Which USB enclosures that have dual USB cables? I have not see any. 
> Also, it would be nice if they had other cable types too.

Different makes and models. I don't have time to find one at the moment,
but have seen Seagate, Western Digital, and others. On this Seagate
page, it says:

"Some of these drives have a 2-pronged USB cable, and most computers
will provide enough electrical power when only one of those prongs is
connected, but some computers will require that both prongs be connected
to provide enough power."

<http://knowledge.seagate.com/articles/en_US/FAQ/207755en>

BTW, the OWC 2.5 inch hard drive enclosure I told you about previously
comes with USB (single connector) and Firewire cables.

-- 
E-mail sent to this address may be devoured by my ravenous SPAM filter.
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JR
0
Jolly
8/25/2014 2:03:46 PM
On 2014-08-25, Ant <ant@zimage.comANT> wrote:
> On 8/24/2014 3:50 PM PT, Jolly Roger typed:
>>> Nice transparency case. Question: Will this still work well with older
>>> machines that don't have USB3 ports and using USB2 ports?
>>
>> USB3 is backward compatible with USB2; so yes. But Firewire 800 is
>> better and faster than USB2, and this drive comes with both USB and
>> Firewire cables. So if the computer in question has a Firewire 800 port,
>> I wouldn't bother with USB at all.
>
> Thanks. I meant the power part. ;)

USB3 is backward compatible with USB2, including power.

Better? : )

-- 
E-mail sent to this address may be devoured by my ravenous SPAM filter.
I often ignore posts from Google. Use a real news client instead.

JR
0
Jolly
8/25/2014 2:06:34 PM
In article <c60ig3F9eb3U1@mid.individual.net>,
 "Rod Speed" <rod.speed.aaa@gmail.com> wrote:

> "isw" <isw@witzend.com> wrote in message 
> news:isw-20962A.21454024082014@[216.168.3.50]...
> > In article <c5v7ihF18ckU1@mid.individual.net>,
> > "Rod Speed" <rod.speed.aaa@gmail.com> wrote:
> >
> >> nospam <nospam@nospam.invalid> wrote
> >> > Rod Speed <rod.speed.aaa@gmail.com> wrote
> >>
> >> >>>>> I know some people prefer to use portable external
> >> >>>>> HDDs, with their power AC connection enclosures
> >> >>>>> or adapters, for reliability and stability.
> >>
> >> >>>> That's mad. By definition external HDDs are less reliable than
> >> >>>> internal drives just because they are easier to drop and knock
> >> >>>> over and because they don1t have as good cooling as you can
> >> >>>> easily achieve with an internal drive in a decent case.
> >>
> >> >>> don't drop them and they're just as reliable.
> >>
> >> >> No, because they are MUCH easier to bump when using them.
> >>
> >> > only for klutzes.
> >>
> >> Bullshit. There are plenty who arent klutzes that don't
> >> even realise that there is a spinning disk in an external
> >> hard drive with the heads flying over the surface and
> >> gyroscopic effects.
> >
> > Although you can feel the gyro effect if you tilt the drive while it's
> > spinning, what is the effect *inside it* that can cause a problem?
> 
> You can end up with a head crash. 

Well, yes, but that's nearly the only mechanical problem an operating 
disk can have. What I'm asking is, what about the gyroscopic effect 
*specifically* is it that causes the crash?

Isaac
0
isw
8/25/2014 4:24:54 PM
In article <c60ijiF9f5vU1@mid.individual.net>,
 "Rod Speed" <rod.speed.aaa@gmail.com> wrote:

> "isw" <isw@witzend.com> wrote in message 
> news:isw-81341E.21535324082014@[216.168.3.50]...
> > In article <c5v7cqF17bvU1@mid.individual.net>,
> > "Rod Speed" <rod.speed.aaa@gmail.com> wrote:
> >
> >> nospam <nospam@nospam.invalid> wrote
> >> > Rod Speed <rod.speed.aaa@gmail.com> wrote
> >>
> >> >>>> I remember using an external DVD-ROM drive that
> >> >>>> used two USB connections that didn't use power AC.
> >>
> >> >>> that's a gross hack.
> >>
> >> >> Its no different to using an external wall
> >> >> wart, much more convenient to use.
> >>
> >> > it's completely different.
> >>
> >> Bullshit.
> >>
> >> > nobody would think of plugging an appliance
> >> > into two outlets to get 30 amps instead of 15.
> >>
> >> USB is different, stupid.
> 
> > Actually, no.
> 
> Fraid so.
> 
> > Using a pair of USB ports *on the same device* is a perfectly
> > legitimate way to get more current than one port will deliver.
> 
> Sure, but is nothing like plugging an appliance
> into two outlets to geet 30 amps instead of 15.

And as I said, I've done that and it works just fine.

> > Currents just add.
> 
> Fraid not.

well, Herr Kirchhoff sure thought so in about 1845, and every electrical 
engineer since his time has depended on it being true, but YMMV ...

If you have an ammeter, you could try it using the USB ports on your 
computer. If you did, I'm fraid you'd be surprised.

Isaac
0
isw
8/25/2014 4:35:11 PM
isw <isw@witzend.com> wrote
> Rod Speed <rod.speed.aaa@gmail.com> wrote
>> isw <isw@witzend.com> wrote
>>> Rod Speed <rod.speed.aaa@gmail.com> wrote
>>>> nospam <nospam@nospam.invalid> wrote
>>>>> Rod Speed <rod.speed.aaa@gmail.com> wrote

>>>>>>>>> I know some people prefer to use portable external
>>>>>>>>> HDDs, with their power AC connection enclosures
>>>>>>>>> or adapters, for reliability and stability.

>>>>>>>> That's mad. By definition external HDDs are less reliable than
>>>>>>>> internal drives just because they are easier to drop and knock
>>>>>>>> over and because they don1t have as good cooling as you can
>>>>>>>> easily achieve with an internal drive in a decent case.

>>>>>>> don't drop them and they're just as reliable.

>>>>>> No, because they are MUCH easier to bump when using them.

>>>>> only for klutzes.

>>>> Bullshit. There are plenty who arent klutzes that don't
>>>> even realise that there is a spinning disk in an external
>>>> hard drive with the heads flying over the surface and
>>>> gyroscopic effects.

>>> Although you can feel the gyro effect if you tilt the drive while it's
>>> spinning, what is the effect *inside it* that can cause a problem?

>> You can end up with a head crash.

> Well, yes, but that's nearly the only mechanical
> problem an operating disk can have.

That's not right, you can get bearing failure too.

> What I'm asking is, what about the gyroscopic
> effect *specifically* is it that causes the crash?

The same effect there has always been with moving a drive when its spinning. 

0
Rod
8/25/2014 6:42:06 PM
isw <isw@witzend.com> wrote
> Rod Speed <rod.speed.aaa@gmail.com> wrote
>> isw <isw@witzend.com> wrote
>>> Rod Speed <rod.speed.aaa@gmail.com> wrote
>>>> nospam <nospam@nospam.invalid> wrote
>>>>> Rod Speed <rod.speed.aaa@gmail.com> wrote

>>>>>>>> I remember using an external DVD-ROM drive that
>>>>>>>> used two USB connections that didn't use power AC.

>>>>>>> that's a gross hack.

>>>>>> Its no different to using an external wall
>>>>>> wart, much more convenient to use.

>>>>> it's completely different.

>>>> Bullshit.

>>>>> nobody would think of plugging an appliance
>>>>> into two outlets to get 30 amps instead of 15.

>>>> USB is different, stupid.

>>> Actually, no.

>> Fraid so.

>>> Using a pair of USB ports *on the same device* is a perfectly
>>> legitimate way to get more current than one port will deliver.

>> Sure, but is nothing like plugging an appliance
>> into two outlets to geet 30 amps instead of 15.

> And as I said, I've done that and it works just fine.

You haven't, actually. There are no appliances that
need 30 amps that plug into a normal outlet that
wont work when plugged into just one and do
work when plugged into two at the same time.

>>> Currents just add.

>> Fraid not.

> well, Herr Kirchhoff sure thought so in about
> 1845, and every electrical engineer since his
> time has depended on it being true,

Not in the that situation where you have an appliance
that is plugged into two outlets at the same time.

> but YMMV ...

> If you have an ammeter, you could try it using the USB ports
> on your computer. If you did, I'm fraid you'd be surprised.

I didn�t say it isnt true with the USB ports, it clearly is.

I was talking about your other appliance claim where it isnt.
You don�t see the appliance taking 15 amps when plugged
into one outlet and 30 amps when plugged into two outlets.
It takes the same total current in both situations, because the
current taken is determined by V=IR.

Its different with USB when the USB port is current limited. 

0
Rod
8/25/2014 6:51:50 PM
nospam wrote:

> have you ever seen a hard drive with a 4 pin firewire port? i sure
> haven't. what would be the point in that? 

How does using a 6-pin Firewire port mandate that its power line must be
used by the device?

For a self-powered external HDD with Firewire or USB port, why would the
manufacture waste adding an A/C power brick or adapter if they were
using the power via the Firewire or USB cable?  For portability?  Nope.
When travelling the external HDD could get its power from the data cable
but even when sitting permanently alongside a desktop the external HDD
could still get its power from the data cable.  The A/C brick or adapter
would be superfluous and add to the manufacturer's production costs if
they got the power from the data cable(s).  They wouldn't be adding an
A/C brick or adapter if their designed relied on the Firewire power.
They could use either the 4- or 6-pin connector.  

Not needing some pins is not sufficient reason to go with a lesser
pinned connector.  Production may be more expensive using the smaller
connector.  Plus the smaller connector isn't as secure as the bigger
one, and a smaller tang will break under the same torque under which the
bigger connector will survive.  They use the 6-pin connector over the
4-pin one for reasons other than supplying power.

For a self-powered external HDD, power via the Firewire and USB ports is
superfluous and you'd have two competing power systems.  I don't see the
point in using power via the Firewire and USB ports if the unit provides
its own power (i.e., A/C brick or adapter).
0
VanguardLH
8/25/2014 7:29:33 PM
Jolly Roger <jollyroger@pobox.com> wrote:

> "Some of these drives have a 2-pronged USB cable, and most computers
> will provide enough electrical power when only one of those prongs is
> connected, but some computers will require that both prongs be connected
> to provide enough power."

Nice to know that.

When I put a SSD in my MacBook Pro, I bought a cheap enclosure fore the
original har drive. That came with a 2-prong USB cable but worked fine
using only one prong.

I had wondered if I was just lucky, but it seems that this is the
commoner situation.
-- 
<http://www.decohen.com>
The Labyrinth of the Heart: Changed Myths for Changing Lives 
book and e-book <http://www.decohen.com/labyrinth.htm>
Send e-mail to the Reply-To address, not the From address.
0
dcohenspam
8/25/2014 9:06:40 PM
In article <1lqy6th.1w19sqn9jplpaN%dcohenspam@talktalk.net>, Daniel
Cohen <dcohenspam@talktalk.net> wrote:

> When I put a SSD in my MacBook Pro, I bought a cheap enclosure fore the
> original har drive. That came with a 2-prong USB cable but worked fine
> using only one prong.
> 
> I had wondered if I was just lucky, but it seems that this is the
> commoner situation.

macbook pros can source 1 amp on usb ports. dual-head cables are not
required.
0
nospam
8/25/2014 10:13:18 PM
In article <ltg2qu$vhv$1@news.albasani.net>, VanguardLH <V@nguard.LH>
wrote:

> > have you ever seen a hard drive with a 4 pin firewire port? i sure
> > haven't. what would be the point in that? 
> 
> How does using a 6-pin Firewire port mandate that its power line must be
> used by the device?

who said anything about mandating? If a device can be bus-powered then
it will probably be designed to do so because that's a desirable
feature.

desktop drives won't be because firewire currently can't source that
much power. it did in the past, and at that time, there were desktop
bus-powered drives.

> For a self-powered external HDD with Firewire or USB port, why would the
> manufacture waste adding an A/C power brick or adapter if they were
> using the power via the Firewire or USB cable?  For portability?  Nope.
> When travelling the external HDD could get its power from the data cable
> but even when sitting permanently alongside a desktop the external HDD
> could still get its power from the data cable.  The A/C brick or adapter
> would be superfluous and add to the manufacturer's production costs if
> they got the power from the data cable(s).  They wouldn't be adding an
> A/C brick or adapter if their designed relied on the Firewire power.
> They could use either the 4- or 6-pin connector.  

many of them do omit the power adapter, although they're cheap so it's
usually included.

> Not needing some pins is not sufficient reason to go with a lesser
> pinned connector.  Production may be more expensive using the smaller
> connector.  Plus the smaller connector isn't as secure as the bigger
> one, and a smaller tang will break under the same torque under which the
> bigger connector will survive.  They use the 6-pin connector over the
> 4-pin one for reasons other than supplying power.
> 
> For a self-powered external HDD, power via the Firewire and USB ports is
> superfluous and you'd have two competing power systems.  I don't see the
> point in using power via the Firewire and USB ports if the unit provides
> its own power (i.e., A/C brick or adapter).

bus-power is a convenience although some users might opt for self-power.
0
nospam
8/25/2014 10:13:20 PM
On 2014-08-25, Daniel Cohen <dcohenspam@talktalk.net> wrote:
> Jolly Roger <jollyroger@pobox.com> wrote:
>
>> "Some of these drives have a 2-pronged USB cable, and most computers
>> will provide enough electrical power when only one of those prongs is
>> connected, but some computers will require that both prongs be connected
>> to provide enough power."
>
> Nice to know that.
>
> When I put a SSD in my MacBook Pro, I bought a cheap enclosure fore the
> original har drive. That came with a 2-prong USB cable but worked fine
> using only one prong.
>
> I had wondered if I was just lucky, but it seems that this is the
> commoner situation.

Whether one of them is sufficient depends on:

a) the power requirements of the hard drive installed inside of the
enclosure
b) the amount of power supplied by the USB port to which it happens to
be connected

-- 
E-mail sent to this address may be devoured by my ravenous SPAM filter.
I often ignore posts from Google. Use a real news client instead.

JR
0
Jolly
8/25/2014 10:28:27 PM
["Followup-To:" header set to comp.sys.mac.hardware.storage.]
On 2014-08-26, Lewis <g.kreme@gmail.com.dontsendmecopies> wrote:
>
> On modern drives? Nothing. It is nearly impossible for a modern disk to
> suffer a head crash.

Not sure what gives you that idea. While newer drives are more shock
resistant, and sudden motion sensor technology in today's Macs can
proactively park the heads if a fall is detected, the fundamental design
of hard drives hasn't changed all that much with respect to how the read
head travels over the surface of the disk platter(s), and they are
therefore still prone to crashing due to excessive shock.

-- 
E-mail sent to this address may be devoured by my ravenous SPAM filter.
I often ignore posts from Google. Use a real news client instead.

JR
0
Jolly
8/26/2014 1:01:01 AM
In article <slrnlvp2vc.fib.g.kreme@amelia.local>, Lewis
<g.kreme@gmail.com.dontsendmecopies> wrote:

> You would have to drop something directly ON the drive, and drives
> normally do not operate exposed to things falling on them. It would also
> take a significant impact.

false. a head crash can occur even without an impact.

seagate drives from about 5 years ago had a manufacturing issue where
the heads actually broke off. 

this unfortunately affected a lot of people. i have two such drives.

> > Knocking a tower on it's side, for example, will not necessarily trip a
> > free-fall sensor, nor will a short 1" drop necessarily give the drive
> > time to react.
> 
> How many head crashes have you seen in the last... oh, let's say 15
> years? I know exactly how many I've seen in that time: *zero* and I've
> dealt with a few hundred drives in that time. Go back 10 more years and
> head crashes were rather common, relatively speaking.

cite?

> You want to argue that it's possible? Go ahead, I never said it wasn't
> possible. Does it happen? And how often?

hard drive failures of any kind are rare. 

however, it's not zero. drives do fail and for various reasons
including a head crash. that's why backups are important.

if a drive fails, the user doesn't give a shit if it's a head crash or
a motor failure or too many bad sectors or some other reason. they want
their data back. hopefully they have backups.
0
nospam
8/26/2014 1:01:01 AM
Okay, so one time? In band camp? isw <isw@witzend.com> was all, like: 
 --> 	 Mon, 25 Aug 2014 09:24:54 -0700 <isw-77ECE0.09245425082014@[216.168.3.50]>
> In article <c60ig3F9eb3U1@mid.individual.net>,
>  "Rod Speed" <rod.speed.aaa@gmail.com> wrote:

>> "isw" <isw@witzend.com> wrote in message 
>> news:isw-20962A.21454024082014@[216.168.3.50]...
>> > In article <c5v7ihF18ckU1@mid.individual.net>,
>> > "Rod Speed" <rod.speed.aaa@gmail.com> wrote:
>> >
>> >> nospam <nospam@nospam.invalid> wrote
>> >> > Rod Speed <rod.speed.aaa@gmail.com> wrote
>> >>
>> >> >>>>> I know some people prefer to use portable external
>> >> >>>>> HDDs, with their power AC connection enclosures
>> >> >>>>> or adapters, for reliability and stability.
>> >>
>> >> >>>> That's mad. By definition external HDDs are less reliable than
>> >> >>>> internal drives just because they are easier to drop and knock
>> >> >>>> over and because they don1t have as good cooling as you can
>> >> >>>> easily achieve with an internal drive in a decent case.
>> >>
>> >> >>> don't drop them and they're just as reliable.
>> >>
>> >> >> No, because they are MUCH easier to bump when using them.
>> >>
>> >> > only for klutzes.
>> >>
>> >> Bullshit. There are plenty who arent klutzes that don't
>> >> even realise that there is a spinning disk in an external
>> >> hard drive with the heads flying over the surface and
>> >> gyroscopic effects.
>> >
>> > Although you can feel the gyro effect if you tilt the drive while it's
>> > spinning, what is the effect *inside it* that can cause a problem?
>> 
>> You can end up with a head crash. 

> Well, yes, but that's nearly the only mechanical problem an operating 
> disk can have. What I'm asking is, what about the gyroscopic effect 
> *specifically* is it that causes the crash?

On modern drives? Nothing. It is nearly impossible for a modern disk to
suffer a head crash.

-- 
If you mixed vodka with orange juice and Milk Of Magnesia, would you get
a Philip's Screwdriver?
0
Lewis
8/26/2014 1:32:51 AM
In article <slrnlvnou3.2m4l.g.kreme@amelia.local>, Lewis
<g.kreme@gmail.com.dontsendmecopies> wrote:

> On modern drives? Nothing. It is nearly impossible for a modern disk to
> suffer a head crash.

drive recovery companies disagree.

maybe you're thinking about ssd which does not have a head to crash.
0
nospam
8/26/2014 1:48:07 AM
In article <c61f0fFfjgcU1@mid.individual.net>,
 "Rod Speed" <rod.speed.aaa@gmail.com> wrote:

> isw <isw@witzend.com> wrote
> > Rod Speed <rod.speed.aaa@gmail.com> wrote
> >> isw <isw@witzend.com> wrote
> >>> Rod Speed <rod.speed.aaa@gmail.com> wrote
> >>>> nospam <nospam@nospam.invalid> wrote
> >>>>> Rod Speed <rod.speed.aaa@gmail.com> wrote
> 
> >>>>>>>> I remember using an external DVD-ROM drive that
> >>>>>>>> used two USB connections that didn't use power AC.
> 
> >>>>>>> that's a gross hack.
> 
> >>>>>> Its no different to using an external wall
> >>>>>> wart, much more convenient to use.
> 
> >>>>> it's completely different.
> 
> >>>> Bullshit.
> 
> >>>>> nobody would think of plugging an appliance
> >>>>> into two outlets to get 30 amps instead of 15.
> 
> >>>> USB is different, stupid.
> 
> >>> Actually, no.
> 
> >> Fraid so.
> 
> >>> Using a pair of USB ports *on the same device* is a perfectly
> >>> legitimate way to get more current than one port will deliver.
> 
> >> Sure, but is nothing like plugging an appliance
> >> into two outlets to geet 30 amps instead of 15.
> 
> > And as I said, I've done that and it works just fine.
> 
> You haven't, actually. There are no appliances that
> need 30 amps that plug into a normal outlet that
> wont work when plugged into just one and do
> work when plugged into two at the same time.

Not ones you buy in a store. Do you ever build things for yourself? I do.

> >>> Currents just add.
> 
> >> Fraid not.
> 
> > well, Herr Kirchhoff sure thought so in about
> > 1845, and every electrical engineer since his
> > time has depended on it being true,
> 
> Not in the that situation where you have an appliance
> that is plugged into two outlets at the same time.
> 
> > but YMMV ...
> 
> > If you have an ammeter, you could try it using the USB ports
> > on your computer. If you did, I'm fraid you'd be surprised.
> 
> I didn�t say it isnt true with the USB ports, it clearly is.
> 
> I was talking about your other appliance claim where it isnt.
> You don�t see the appliance taking 15 amps when plugged
> into one outlet and 30 amps when plugged into two outlets.
> It takes the same total current in both situations, because the
> current taken is determined by V=IR.

It's pretty clear that the item drawing current has to be able to draw 
more than 15 Amps for the two-outlet trick to be of any use. IOW, you 
need to have a load that would draw more than 15 Amps. at local line 
voltage.

In fact, what I built that worked that way was a portable light board 
for in-the-round theater productions. 15 Amps couldn't handle enough 
lights, but 30 Amps (from two outlets on different breakers) could.

> Its different with USB when the USB port is current limited. 

If a USB port's source ability is limited to, say, 0.5 Amps, then 
combining two of them you can get pretty close to a full amp (depends on 
how well the two hook-ups are balanced). Provided, of course, that the 
load can actually draw the extra current -- and something like a disk 
drive certainly could.

Isaac
0
isw
8/26/2014 4:31:24 AM
In article <c61eofFfhk7U1@mid.individual.net>,
 "Rod Speed" <rod.speed.aaa@gmail.com> wrote:

> isw <isw@witzend.com> wrote
> > Rod Speed <rod.speed.aaa@gmail.com> wrote
> >> isw <isw@witzend.com> wrote
> >>> Rod Speed <rod.speed.aaa@gmail.com> wrote
> >>>> nospam <nospam@nospam.invalid> wrote
> >>>>> Rod Speed <rod.speed.aaa@gmail.com> wrote
> 
> >>>>>>>>> I know some people prefer to use portable external
> >>>>>>>>> HDDs, with their power AC connection enclosures
> >>>>>>>>> or adapters, for reliability and stability.
> 
> >>>>>>>> That's mad. By definition external HDDs are less reliable than
> >>>>>>>> internal drives just because they are easier to drop and knock
> >>>>>>>> over and because they don1t have as good cooling as you can
> >>>>>>>> easily achieve with an internal drive in a decent case.
> 
> >>>>>>> don't drop them and they're just as reliable.
> 
> >>>>>> No, because they are MUCH easier to bump when using them.
> 
> >>>>> only for klutzes.
> 
> >>>> Bullshit. There are plenty who arent klutzes that don't
> >>>> even realise that there is a spinning disk in an external
> >>>> hard drive with the heads flying over the surface and
> >>>> gyroscopic effects.
> 
> >>> Although you can feel the gyro effect if you tilt the drive while it's
> >>> spinning, what is the effect *inside it* that can cause a problem?
> 
> >> You can end up with a head crash.
> 
> > Well, yes, but that's nearly the only mechanical
> > problem an operating disk can have.
> 
> That's not right, you can get bearing failure too.
> 
> > What I'm asking is, what about the gyroscopic
> > effect *specifically* is it that causes the crash?
> 
> The same effect there has always been with moving a drive when its spinning. 

My point exactly: there is nothing at all about the gyroscopic effect 
that makes a disk malfunction any more likely.

Isaac
0
isw
8/26/2014 4:33:42 AM
In the last episode of <yNadnZiHktfKoWfOnZ2dnUVZ_uidnZ2d@earthlink.com>,
Ant <ant@zimage.comANT> said:

>On 8/24/2014 12:13 PM PT, nospam typed:
>> just about every 2.5" enclosure can be bus-powered.
>> however, usb power can be unreliable.
>
>What about other connection types like ESATA, Firewire, Thunderbolt, 
>etc. if they exist on the computers?

Beyond the other answers, there's a eSATA extension called eSATAp which
provides power. However, it's just a USB power supply in a eSATA port,
and it's not actually an official standard at this point. Still, you'll
find implementations do exist.

https://en.wikipedia.org/wiki/ESATAp

All eSATAp ports provide 5V, desktops often also provide 12V. The amount
varies per implementation, somewhere between a USB2 port's capabilities
and a full SATA power connector dedicated to the eSATAp.

This tends to be a good solution for desktops, but less so for laptops,
and you absolutely cannot rely on being able to plug into unknown
computers even if your drive is the 5V version.

Still, if you control the hardware and can ensure an eSATAp port will be
available, it's a good solution.

-- 
What do you want you moon-faced assassin of joy?
0
DevilsPGD
8/26/2014 5:02:11 AM
In the last episode of <slrnlvnou3.2m4l.g.kreme@amelia.local>, Lewis
<g.kreme@gmail.com.dontsendmecopies> said:

>On modern drives? Nothing. It is nearly impossible for a modern disk to
>suffer a head crash.

If you drop the whole device, it will generally park the heads and you
won't suffer a head crash, this is true. 

However, if the impact happens without a free-fall drop or other warning
sign, the sensors won't know to park the heads and you can crash the
heads reasonably easily. This can happen if the initial impact is to the
drive (or case) itself.

-- 
What do you want you moon-faced assassin of joy?
0
DevilsPGD
8/26/2014 5:07:34 AM
Okay, so one time? In band camp? Jolly Roger <jollyroger@pobox.com> was all, like: 
 --> 	 26 Aug 2014 03:56:11 GMT <c62eqrFlntfU2@mid.individual.net>
> ["Followup-To:" header set to comp.sys.mac.hardware.storage.]
> On 2014-08-26, Lewis <g.kreme@gmail.com.dontsendmecopies> wrote:
>>
>> On modern drives? Nothing. It is nearly impossible for a modern disk to
>> suffer a head crash.

> Not sure what gives you that idea. While newer drives are more shock
> resistant, and sudden motion sensor technology in today's Macs can
> proactively park the heads if a fall is detected, the fundamental design
> of hard drives hasn't changed all that much with respect to how the read
> head travels over the surface of the disk platter(s), and they are
> therefore still prone to crashing due to excessive shock.

If you hit one with a sledge hammer you might cause the heads to crash.
Maybe. Probably not. But at that point, you'll have other problems.

I stand by what I said, nearly impossible for a modern disk to suffer a
head crash.

-- 
Of course, there were various groups seeking his overthrow, and this was
right and proper and the sign of a vigorous and healthy society. No-one
could call him unreasonable about the matter. Why, hadn't he founded
most of them himself? And what was so beautiful was the way they spent
nearly all their time bickering with one another. Human nature, the
Patrician always said, was a marvelous thing. Once you understood where
its levers were. --Guards! Guards!
0
Lewis
8/26/2014 5:21:26 AM
Okay, so one time? In band camp? DevilsPGD <boogabooga@crazyhat.net> was all, like: 
 --> 	 Mon, 25 Aug 2014 22:07:34 -0700 <8c5ov99e3asl68c176oknbl1l8ncn9gel8@4ax.com>
> In the last episode of <slrnlvnou3.2m4l.g.kreme@amelia.local>, Lewis
> <g.kreme@gmail.com.dontsendmecopies> said:

>>On modern drives? Nothing. It is nearly impossible for a modern disk to
>>suffer a head crash.

> If you drop the whole device, it will generally park the heads and you
> won't suffer a head crash, this is true. 

> However, if the impact happens without a free-fall drop or other warning
> sign, the sensors won't know to park the heads and you can crash the
> heads reasonably easily. This can happen if the initial impact is to the
> drive (or case) itself.

Sure, it is possible. It's very unlikely, and rather difficult. I said
"nearly impossible" not "impossible".

-- 
Nothing gold can stay -- Robert Frost Stay gold -- Johnny Cade
0
Lewis
8/26/2014 5:22:38 AM
In the last episode of <slrnlvo6cv.en4.g.kreme@amelia.local>, Lewis
<g.kreme@gmail.com.dontsendmecopies> said:

>Okay, so one time? In band camp? DevilsPGD <boogabooga@crazyhat.net> was all, like: 
> --> 	 Mon, 25 Aug 2014 22:07:34 -0700 <8c5ov99e3asl68c176oknbl1l8ncn9gel8@4ax.com>
>> In the last episode of <slrnlvnou3.2m4l.g.kreme@amelia.local>, Lewis
>> <g.kreme@gmail.com.dontsendmecopies> said:
>
>>>On modern drives? Nothing. It is nearly impossible for a modern disk to
>>>suffer a head crash.
>
>> If you drop the whole device, it will generally park the heads and you
>> won't suffer a head crash, this is true. 
>
>> However, if the impact happens without a free-fall drop or other warning
>> sign, the sensors won't know to park the heads and you can crash the
>> heads reasonably easily. This can happen if the initial impact is to the
>> drive (or case) itself.
>
>Sure, it is possible. It's very unlikely, and rather difficult. I said
>"nearly impossible" not "impossible".

How is that difficult? Any sudden impact that doesn't start with a fall
can make it happen. Dropping something on the drive, or on something
that can pass the force to the drive (for example a metal box that is
physically attached to the drive's frame) can do it.

Knocking a tower on it's side, for example, will not necessarily trip a
free-fall sensor, nor will a short 1" drop necessarily give the drive
time to react.

-- 
What do you want you moon-faced assassin of joy?
0
DevilsPGD
8/26/2014 6:55:08 AM
On 8/25/2014 7:06 AM PT, Jolly Roger typed:

> On 2014-08-25, Ant <ant@zimage.comANT> wrote:
>> On 8/24/2014 3:50 PM PT, Jolly Roger typed:
>>>> Nice transparency case. Question: Will this still work well with older
>>>> machines that don't have USB3 ports and using USB2 ports?
>>>
>>> USB3 is backward compatible with USB2; so yes. But Firewire 800 is
>>> better and faster than USB2, and this drive comes with both USB and
>>> Firewire cables. So if the computer in question has a Firewire 800 port,
>>> I wouldn't bother with USB at all.
>>
>> Thanks. I meant the power part. ;)
>
> USB3 is backward compatible with USB2, including power.
>
> Better? : )

Yes. :)
-- 
"It's like stepping on ants... I don't step on ants, Major." --Odo and 
Kira from Star Trek: Deep Space Nine
    /\___/\         Ant(Dude) @ http://antfarm.ma.cx (Personal Web Site)
   / /\ /\ \                Ant's Quality Foraged Links: http://aqfl.net
  | |o   o| |
     \ _ /        If crediting, then use Ant nickname and AQFL URL/link.
      ( )         If e-mailing, then axe ANT from its address if needed.
Ant is currently not listening to any songs on this computer.
0
Ant
8/26/2014 7:46:36 AM
Okay, so one time? In band camp? DevilsPGD <boogabooga@crazyhat.net> was all, like: 
 --> 	 Mon, 25 Aug 2014 23:55:08 -0700 <afbov9l23n91jkou6celcssr275m738ps6@4ax.com>
> In the last episode of <slrnlvo6cv.en4.g.kreme@amelia.local>, Lewis
> <g.kreme@gmail.com.dontsendmecopies> said:

>>Okay, so one time? In band camp? DevilsPGD <boogabooga@crazyhat.net> was all, like: 
>> --> 	 Mon, 25 Aug 2014 22:07:34 -0700 <8c5ov99e3asl68c176oknbl1l8ncn9gel8@4ax.com>
>>> In the last episode of <slrnlvnou3.2m4l.g.kreme@amelia.local>, Lewis
>>> <g.kreme@gmail.com.dontsendmecopies> said:
>>
>>>>On modern drives? Nothing. It is nearly impossible for a modern disk to
>>>>suffer a head crash.
>>
>>> If you drop the whole device, it will generally park the heads and you
>>> won't suffer a head crash, this is true. 
>>
>>> However, if the impact happens without a free-fall drop or other warning
>>> sign, the sensors won't know to park the heads and you can crash the
>>> heads reasonably easily. This can happen if the initial impact is to the
>>> drive (or case) itself.
>>
>>Sure, it is possible. It's very unlikely, and rather difficult. I said
>>"nearly impossible" not "impossible".

> How is that difficult? Any sudden impact that doesn't start with a fall
> can make it happen. Dropping something on the drive, or on something
> that can pass the force to the drive (for example a metal box that is
> physically attached to the drive's frame) can do it.

You would have to drop something directly ON the drive, and drives
normally do not operate exposed to things falling on them. It would also
take a significant impact.

> Knocking a tower on it's side, for example, will not necessarily trip a
> free-fall sensor, nor will a short 1" drop necessarily give the drive
> time to react.

How many head crashes have you seen in the last... oh, let's say 15
years? I know exactly how many I've seen in that time: *zero* and I've
dealt with a few hundred drives in that time. Go back 10 more years and
head crashes were rather common, relatively speaking.

You want to argue that it's possible? Go ahead, I never said it wasn't
possible. Does it happen? And how often?

-- 
When the chips are down, the buffalo's empty.
0
Lewis
8/26/2014 1:30:21 PM
On 2014-08-26, Lewis <g.kreme@gmail.com.dontsendmecopies> wrote:
> Okay, so one time? In band camp? Jolly Roger <jollyroger@pobox.com> was all, like: 
>  --> 	 26 Aug 2014 03:56:11 GMT <c62eqrFlntfU2@mid.individual.net>
>> ["Followup-To:" header set to comp.sys.mac.hardware.storage.]
>> On 2014-08-26, Lewis <g.kreme@gmail.com.dontsendmecopies> wrote:
>>>
>>> On modern drives? Nothing. It is nearly impossible for a modern disk to
>>> suffer a head crash.
>
>> Not sure what gives you that idea. While newer drives are more shock
>> resistant, and sudden motion sensor technology in today's Macs can
>> proactively park the heads if a fall is detected, the fundamental design
>> of hard drives hasn't changed all that much with respect to how the read
>> head travels over the surface of the disk platter(s), and they are
>> therefore still prone to crashing due to excessive shock.
>
> If you hit one with a sledge hammer you might cause the heads to crash.
> Maybe. Probably not. But at that point, you'll have other problems.
>
> I stand by what I said, nearly impossible for a modern disk to suffer a
> head crash.

Actual experience says you are wrong. To wit: I crashed a 2 TB drive
recently simply by accidentally tapping it with the head of a
screwdriver while it was running. The screwdriver slipped out of my
hand, and as I caught it, the head just barely tapped the top of the
drive chassis. I did catch it, and I did prevent it from hitting harder
than it did. It was a very slight tap. No hard force or sledge hammer
was involved. Immediately after that, I heard the drive head go into a
repetitive seek mode, trying to re-read part of the volume, and the
drive was effectively inoperable after that. After pulling it apart, I
could see the visible strike mark the head made on the surface of the
plater. So I know for a fact it was a head crash. If head crashes were
near impossibilities as you suggest, this would not have happened - only
it did happen. 

-- 
E-mail sent to this address may be devoured by my ravenous SPAM filter.
I often ignore posts from Google. Use a real news client instead.

JR
0
Jolly
8/26/2014 1:54:54 PM
["Followup-To:" header set to comp.sys.mac.hardware.storage.]
On 2014-08-26, DevilsPGD <boogabooga@crazyhat.net> wrote:
> In the last episode of <slrnlvnou3.2m4l.g.kreme@amelia.local>, Lewis
><g.kreme@gmail.com.dontsendmecopies> said:
>
>>On modern drives? Nothing. It is nearly impossible for a modern disk to
>>suffer a head crash.
>
> If you drop the whole device, it will generally park the heads and you
> won't suffer a head crash, this is true. 
>
> However, if the impact happens without a free-fall drop or other warning
> sign, the sensors won't know to park the heads and you can crash the
> heads reasonably easily. This can happen if the initial impact is to the
> drive (or case) itself.

Correct. Earthquake, anyone? ; ) In this light, "nearly impossible" is
extremely misleading, or flat-out wrong, depending on one's mood. : )

-- 
E-mail sent to this address may be devoured by my ravenous SPAM filter.
I often ignore posts from Google. Use a real news client instead.

JR
0
Jolly
8/26/2014 1:57:34 PM
["Followup-To:" header set to comp.sys.mac.hardware.storage.]
On 2014-08-26, Lewis <g.kreme@gmail.com.dontsendmecopies> wrote:
> Okay, so one time? In band camp? DevilsPGD <boogabooga@crazyhat.net> was all, like: 
>>>
>>>> However, if the impact happens without a free-fall drop or other warning
>>>> sign, the sensors won't know to park the heads and you can crash the
>>>> heads reasonably easily. This can happen if the initial impact is to the
>>>> drive (or case) itself.
>>>
>>> Sure, it is possible. It's very unlikely, and rather difficult. I said
>>> "nearly impossible" not "impossible".

The problem is the words you chose. "Unlikely in optimal conditions" is
more correct since it remains a possibility.

>> How is that difficult? Any sudden impact that doesn't start with a fall
>> can make it happen. Dropping something on the drive, or on something
>> that can pass the force to the drive (for example a metal box that is
>> physically attached to the drive's frame) can do it.
>
> You would have to drop something directly ON the drive, and drives
> normally do not operate exposed to things falling on them. It would also
> take a significant impact.

Experience shows it doesn't take much force at all to cause the head to
travel the 3 or so nanometers needed to strike the platter surface. All
that is needed is sufficient force at the right angle to cause the head
to move in a bad direction. And some hard drive enclosures do not offer
much in the way of shock protection. So an external drive can be quite
susceptible to head-crashing shocks. 

>> Knocking a tower on it's side, for example, will not necessarily trip a
>> free-fall sensor, nor will a short 1" drop necessarily give the drive
>> time to react.
>
> How many head crashes have you seen in the last... oh, let's say 15
> years? I know exactly how many I've seen in that time: *zero* and I've
> dealt with a few hundred drives in that time. Go back 10 more years and
> head crashes were rather common, relatively speaking.

I've dealt with a fair share of hard drives during the past 15 years and
have seen a handful crash.

> You want to argue that it's possible? Go ahead, I never said it wasn't
> possible. Does it happen? And how often?

Your choice of words is the problem. You said it's "nearly impossible",
which is untrue because it's quite possible under the right
circumstances, so it would be more accurate to say head crashes are
*unlikely* in *optimal* conditions.

-- 
E-mail sent to this address may be devoured by my ravenous SPAM filter.
I often ignore posts from Google. Use a real news client instead.

JR
0
Jolly
8/26/2014 2:08:04 PM
In article <8c5ov99e3asl68c176oknbl1l8ncn9gel8@4ax.com>,
 DevilsPGD <boogabooga@crazyhat.net> wrote:

> In the last episode of <slrnlvnou3.2m4l.g.kreme@amelia.local>, Lewis
> <g.kreme@gmail.com.dontsendmecopies> said:
> 
> >On modern drives? Nothing. It is nearly impossible for a modern disk to
> >suffer a head crash.
> 
> If you drop the whole device, it will generally park the heads and you
> won't suffer a head crash, this is true.

Some portable computers include free-fall sensors, which *with the 
participation of the computer's OS*, can park the heads, but I don't 
think that many bare drives have them, so an external drive won't have 
any auto-park protection from a drop off the table top.

Further, none of the accelerometer systems can provide protection 
against sudden sharp shocks.

Isaac
0
isw
8/26/2014 4:16:36 PM
isw <isw@witzend.com> wrote
> Rod Speed <rod.speed.aaa@gmail.com> wrote
>> isw <isw@witzend.com> wrote
>>> Rod Speed <rod.speed.aaa@gmail.com> wrote
>>>> isw <isw@witzend.com> wrote
>>>>> Rod Speed <rod.speed.aaa@gmail.com> wrote
>>>>>> nospam <nospam@nospam.invalid> wrote
>>>>>>> Rod Speed <rod.speed.aaa@gmail.com> wrote

>>>>>>>>>> I remember using an external DVD-ROM drive that
>>>>>>>>>> used two USB connections that didn't use power AC.

>>>>>>>>> that's a gross hack.

>>>>>>>> Its no different to using an external wall
>>>>>>>> wart, much more convenient to use.

>>>>>>> it's completely different.

>>>>>> Bullshit.

>>>>>>> nobody would think of plugging an appliance
>>>>>>> into two outlets to get 30 amps instead of 15.

>>>>>> USB is different, stupid.

>>>>> Actually, no.

>>>> Fraid so.

>>>>> Using a pair of USB ports *on the same device* is a perfectly
>>>>> legitimate way to get more current than one port will deliver.

>>>> Sure, but is nothing like plugging an appliance
>>>> into two outlets to geet 30 amps instead of 15.

>>> And as I said, I've done that and it works just fine.

>> You haven't, actually. There are no appliances that
>> need 30 amps that plug into a normal outlet that
>> wont work when plugged into just one and do
>> work when plugged into two at the same time.

> Not ones you buy in a store. Do you ever build things for yourself? I do.

Yep, been doing that since before you were even born,
and built and wired my entire house as well, and powered
the entire house from the builder's temporary supply for
quite a while until the supply authority eventually chucked
a wobbly and demanded I connect the house properly.

>>>>> Currents just add.

>>>> Fraid not.

>>> well, Herr Kirchhoff sure thought so in about
>>> 1845, and every electrical engineer since his
>>> time has depended on it being true,

>> Not in the that situation where you have an appliance
>> that is plugged into two outlets at the same time.

>>> but YMMV ...

>>> If you have an ammeter, you could try it using the USB ports
>>> on your computer. If you did, I'm fraid you'd be surprised.

>> I didn�t say it isnt true with the USB ports, it clearly is.

>> I was talking about your other appliance claim where it isnt.
>> You don�t see the appliance taking 15 amps when plugged
>> into one outlet and 30 amps when plugged into two outlets.
>> It takes the same total current in both situations, because the
>> current taken is determined by V=IR.

> It's pretty clear that the item drawing current has to be able to
> draw more than 15 Amps for the two-outlet trick to be of any use.

And there arent any appliances like that.

> IOW, you need to have a load that would
> draw more than 15 Amps. at local line voltage.

And there arent any appliances like that.

> In fact, what I built that worked that way was a portable light board
> for in-the-round theater productions. 15 Amps couldn't handle enough
> lights, but 30 Amps (from two outlets on different breakers) could.

That's not an appliance.

>> Its different with USB when the USB port is current limited.

> If a USB port's source ability is limited to, say, 0.5 Amps, then
> combining two of them you can get pretty close to a full amp
> (depends on how well the two hook-ups are balanced).

Yes, but the mains doesn�t work like that.

> Provided, of course, that the load can actually draw the extra
> current -- and something like a disk drive certainly could.

Not necessarily with the smaller external drives. 

0
Rod
8/26/2014 8:16:12 PM
Ant wrote:

> Hello.
> 
> I know some people prefer to use portable external HDDs, with their 
> power AC connection enclosures or adapters, for reliability and 
> stability. Some people prefer those tiny HDDs with only their USB 
> connections for both power and accessing data (easiest and lightest).
> 
> Are there any external HDD adapters and enclosures that do not use power 
> AC connections? I don't know mind having to use another 
> USB/Firewire/ESATA/Thunderbolt cable connection to the computer when 
> using one already instead of having to carry its power AC cable and 
> brick. I have not seen one yet. Or is it not possible?
> 
> Thank you in advance. :)

So after all the suggestions in the other responses that are based on
unknown hardware, what port types are actually available in your present
computer?  Or was this just an curiosity inquiry to possibly affect on
what you might include in a later build?
0
VanguardLH
8/26/2014 8:18:06 PM
isw <isw@witzend.com> wrote
> Rod Speed <rod.speed.aaa@gmail.com> wrote
>> isw <isw@witzend.com> wrote
>>> Rod Speed <rod.speed.aaa@gmail.com> wrote
>>>> isw <isw@witzend.com> wrote
>>>>> Rod Speed <rod.speed.aaa@gmail.com> wrote
>>>>>> nospam <nospam@nospam.invalid> wrote
>>>>>>> Rod Speed <rod.speed.aaa@gmail.com> wrote

>>>>>>>>>>> I know some people prefer to use portable external
>>>>>>>>>>> HDDs, with their power AC connection enclosures
>>>>>>>>>>> or adapters, for reliability and stability.

>>>>>>>>>> That's mad. By definition external HDDs are less reliable than
>>>>>>>>>> internal drives just because they are easier to drop and knock
>>>>>>>>>> over and because they don1t have as good cooling as you can
>>>>>>>>>> easily achieve with an internal drive in a decent case.

>>>>>>>>> don't drop them and they're just as reliable.

>>>>>>>> No, because they are MUCH easier to bump when using them.

>>>>>>> only for klutzes.

>>>>>> Bullshit. There are plenty who arent klutzes that don't
>>>>>> even realise that there is a spinning disk in an external
>>>>>> hard drive with the heads flying over the surface and
>>>>>> gyroscopic effects.

>>>>> Although you can feel the gyro effect if you tilt the drive while it's
>>>>> spinning, what is the effect *inside it* that can cause a problem?

>>>> You can end up with a head crash.

>>> Well, yes, but that's nearly the only mechanical
>>> problem an operating disk can have.

>> That's not right, you can get bearing failure too.

>>> What I'm asking is, what about the gyroscopic
>>> effect *specifically* is it that causes the crash?

>> The same effect there has always been with moving a drive when its 
>> spinning.

> My point exactly:

Nope.

> there is nothing at all about the gyroscopic effect
> that makes a disk malfunction any more likely.

Have fun explaining why normal desktop drives have
failed when the system is moved with the drives spinning.

And you can get quite high G loads just by letting the drive
down hard as you place it on the desktop when running. 

0
Rod
8/26/2014 8:19:35 PM

"Lewis" <g.kreme@gmail.com.dontsendmecopies> wrote in message 
news:slrnlvp2vc.fib.g.kreme@amelia.local...
> Okay, so one time? In band camp? DevilsPGD <boogabooga@crazyhat.net> was 
> all, like:
> --> Mon, 25 Aug 2014 23:55:08 -0700 
> <afbov9l23n91jkou6celcssr275m738ps6@4ax.com>
>> In the last episode of <slrnlvo6cv.en4.g.kreme@amelia.local>, Lewis
>> <g.kreme@gmail.com.dontsendmecopies> said:
>
>>>Okay, so one time? In band camp? DevilsPGD <boogabooga@crazyhat.net> was 
>>>all, like:
>>> --> Mon, 25 Aug 2014 22:07:34 -0700 
>>> <8c5ov99e3asl68c176oknbl1l8ncn9gel8@4ax.com>
>>>> In the last episode of <slrnlvnou3.2m4l.g.kreme@amelia.local>, Lewis
>>>> <g.kreme@gmail.com.dontsendmecopies> said:
>>>
>>>>>On modern drives? Nothing. It is nearly impossible for a modern disk to
>>>>>suffer a head crash.
>>>
>>>> If you drop the whole device, it will generally park the heads and you
>>>> won't suffer a head crash, this is true.
>>>
>>>> However, if the impact happens without a free-fall drop or other 
>>>> warning
>>>> sign, the sensors won't know to park the heads and you can crash the
>>>> heads reasonably easily. This can happen if the initial impact is to 
>>>> the
>>>> drive (or case) itself.
>>>
>>>Sure, it is possible. It's very unlikely, and rather difficult. I said
>>>"nearly impossible" not "impossible".
>
>> How is that difficult? Any sudden impact that doesn't start with a fall
>> can make it happen. Dropping something on the drive, or on something
>> that can pass the force to the drive (for example a metal box that is
>> physically attached to the drive's frame) can do it.

> You would have to drop something directly ON the drive,

Yes.

> and drives normally do not operate exposed to things falling on them.

External drives do when you have then on the desktop next
to the device.

> It would also take a significant impact.

Yes, but it isnt that uncommon to drop things.

>> Knocking a tower on it's side, for example, will not necessarily trip a
>> free-fall sensor, nor will a short 1" drop necessarily give the drive
>> time to react.
>
> How many head crashes have you seen in the last... oh, let's say 15
> years? I know exactly how many I've seen in that time: *zero* and I've
> dealt with a few hundred drives in that time. Go back 10 more years and
> head crashes were rather common, relatively speaking.

But you treat the drives carefully, don�t throw them around when spinning.

> You want to argue that it's possible? Go ahead, I never said it wasn't
> possible. Does it happen? And how often?
 

0
0hjk
8/26/2014 8:23:44 PM
Okay, so one time? In band camp? Jolly Roger <jollyroger@pobox.com> was all, like: 
 --> 	 26 Aug 2014 13:54:54 GMT <c63hteFspksU1@mid.individual.net>
> On 2014-08-26, Lewis <g.kreme@gmail.com.dontsendmecopies> wrote:
>> Okay, so one time? In band camp? Jolly Roger <jollyroger@pobox.com> was all, like: 
>>  --> 	 26 Aug 2014 03:56:11 GMT <c62eqrFlntfU2@mid.individual.net>
>>> ["Followup-To:" header set to comp.sys.mac.hardware.storage.]
>>> On 2014-08-26, Lewis <g.kreme@gmail.com.dontsendmecopies> wrote:
>>>>
>>>> On modern drives? Nothing. It is nearly impossible for a modern disk to
>>>> suffer a head crash.
>>
>>> Not sure what gives you that idea. While newer drives are more shock
>>> resistant, and sudden motion sensor technology in today's Macs can
>>> proactively park the heads if a fall is detected, the fundamental design
>>> of hard drives hasn't changed all that much with respect to how the read
>>> head travels over the surface of the disk platter(s), and they are
>>> therefore still prone to crashing due to excessive shock.
>>
>> If you hit one with a sledge hammer you might cause the heads to crash.
>> Maybe. Probably not. But at that point, you'll have other problems.
>>
>> I stand by what I said, nearly impossible for a modern disk to suffer a
>> head crash.

> Actual experience says you are wrong. To wit: I crashed a 2 TB drive
> recently simply by accidentally tapping it with the head of a
> screwdriver while it was running. The screwdriver slipped out of my
> hand, and as I caught it, the head just barely tapped the top of the
> drive chassis. I did catch it, and I did prevent it from hitting harder
> than it did. It was a very slight tap. No hard force or sledge hammer
> was involved. Immediately after that, I heard the drive head go into a
> repetitive seek mode, trying to re-read part of the volume, and the
> drive was effectively inoperable after that. After pulling it apart, I
> could see the visible strike mark the head made on the surface of the
> plater. So I know for a fact it was a head crash. If head crashes were
> near impossibilities as you suggest, this would not have happened - only
> it did happen. 

As I said, it takes dropping something on the drive and drives do not
normally operate exposed to things dropping on them. And even in that
case of running the drive exposed, you were unlucky that the drive was
actually active at that precise time the screwdriver hit.

-- 
For more than a thousand generations the Jedi were the guardians of
peace and justice in the galaxy. Before the dark times. Before the
Empire.
0
Lewis
8/26/2014 10:29:06 PM
On 2014-08-26, Lewis <g.kreme@gmail.com.dontsendmecopies> wrote:
>
> As I said, it takes dropping something on the drive and drives do not
> normally operate exposed to things dropping on them.

Bull. Any external hard drive sitting on a desk top can easily have
something dropped on it.

> And even in that case of running the drive exposed, you were unlucky
> that the drive was actually active at that precise time the
> screwdriver hit.

The point is it's not "nearly impossible", which is a clear exaggeration,
but instead "likely or unlikely, depending on individual circumstances".

-- 
E-mail sent to this address may be devoured by my ravenous SPAM filter.
I often ignore posts from Google. Use a real news client instead.

JR
0
Jolly
8/26/2014 11:40:58 PM
In the last episode of <isw-4FAF80.09163626082014@[216.168.3.50]>, isw
<isw@witzend.com> said:

>Some portable computers include free-fall sensors, which *with the 
>participation of the computer's OS*, can park the heads, but I don't 
>think that many bare drives have them, so an external drive won't have 
>any auto-park protection from a drop off the table top.

There's no reason that the OS need be involved, the drive could shut
down until either the impact or the free-fall event is over, from the OS
this isn't any different than a drive which pauses to attempt a repair
of a particular sector.

But this is an implementation detail, I'm not really sure what modern
drives actually implement (and nor do I really care since my portable
devices are all solid state and I treat my desktops and servers with
appropriate caution)

-- 
I wouldn't be caught dead with a necrophiliac. 
0
DevilsPGD
8/27/2014 2:27:26 AM
["Followup-To:" header set to comp.sys.mac.hardware.storage.]
On 2014-08-27, DevilsPGD <boogabooga@crazyhat.net> wrote:
> In the last episode of <isw-4FAF80.09163626082014@[216.168.3.50]>, isw
><isw@witzend.com> said:
>
>>Some portable computers include free-fall sensors, which *with the 
>>participation of the computer's OS*, can park the heads, but I don't 
>>think that many bare drives have them, so an external drive won't have 
>>any auto-park protection from a drop off the table top.
>
> There's no reason that the OS need be involved, the drive could shut
> down until either the impact or the free-fall event is over, from the OS
> this isn't any different than a drive which pauses to attempt a repair
> of a particular sector.

That's assuming the sensor is built into the hard drive itself. Not all
hard drives have such sensors. Without such a sensor, the drive is
effectively blind to the tragedy that is about to happen, and therefore
can't react. That's where Apple's sudden motion sensor comes into play: 

<http://support.apple.com/kb/HT1935>

-- 
E-mail sent to this address may be devoured by my ravenous SPAM filter.
I often ignore posts from Google. Use a real news client instead.

JR
0
Jolly
8/27/2014 4:30:52 AM
In article <c648h4F3dm4U1@mid.individual.net>,
 "Rod Speed" <rod.speed.aaa@gmail.com> wrote:

> isw <isw@witzend.com> wrote
> > Rod Speed <rod.speed.aaa@gmail.com> wrote
> >> isw <isw@witzend.com> wrote
> >>> Rod Speed <rod.speed.aaa@gmail.com> wrote
> >>>> isw <isw@witzend.com> wrote
> >>>>> Rod Speed <rod.speed.aaa@gmail.com> wrote
> >>>>>> nospam <nospam@nospam.invalid> wrote
> >>>>>>> Rod Speed <rod.speed.aaa@gmail.com> wrote
> 
> >>>>>>>>>>> I know some people prefer to use portable external
> >>>>>>>>>>> HDDs, with their power AC connection enclosures
> >>>>>>>>>>> or adapters, for reliability and stability.
> 
> >>>>>>>>>> That's mad. By definition external HDDs are less reliable than
> >>>>>>>>>> internal drives just because they are easier to drop and knock
> >>>>>>>>>> over and because they don1t have as good cooling as you can
> >>>>>>>>>> easily achieve with an internal drive in a decent case.
> 
> >>>>>>>>> don't drop them and they're just as reliable.
> 
> >>>>>>>> No, because they are MUCH easier to bump when using them.
> 
> >>>>>>> only for klutzes.
> 
> >>>>>> Bullshit. There are plenty who arent klutzes that don't
> >>>>>> even realise that there is a spinning disk in an external
> >>>>>> hard drive with the heads flying over the surface and
> >>>>>> gyroscopic effects.
> 
> >>>>> Although you can feel the gyro effect if you tilt the drive while it's
> >>>>> spinning, what is the effect *inside it* that can cause a problem?
> 
> >>>> You can end up with a head crash.
> 
> >>> Well, yes, but that's nearly the only mechanical
> >>> problem an operating disk can have.
> 
> >> That's not right, you can get bearing failure too.
> 
> >>> What I'm asking is, what about the gyroscopic
> >>> effect *specifically* is it that causes the crash?
> 
> >> The same effect there has always been with moving a drive when its 
> >> spinning.
> 
> > My point exactly:
> 
> Nope.
> 
> > there is nothing at all about the gyroscopic effect
> > that makes a disk malfunction any more likely.
> 
> Have fun explaining why normal desktop drives have
> failed when the system is moved with the drives spinning.
> 
> And you can get quite high G loads just by letting the drive
> down hard as you place it on the desktop when running. 

Correlation is not causation. Clearly, just about the only time a modern 
disk can have a head crash is when the head is flying above the disk, 
and the only time it is doing that is when the platter is rotating.

But the issue we're discussing is the gyroscopic behavior of the 
spinning platter. Can you make a case that it is *specifically* the 
gyroscopic effect that causes the crash? I cannot think of any reason 
why it would.

Isaac
0
isw
8/27/2014 5:00:03 AM
In article <c648aqF3ce1U1@mid.individual.net>,
 "Rod Speed" <rod.speed.aaa@gmail.com> wrote:

> isw <isw@witzend.com> wrote
> > Rod Speed <rod.speed.aaa@gmail.com> wrote
> >> isw <isw@witzend.com> wrote
> >>> Rod Speed <rod.speed.aaa@gmail.com> wrote
> >>>> isw <isw@witzend.com> wrote
> >>>>> Rod Speed <rod.speed.aaa@gmail.com> wrote
> >>>>>> nospam <nospam@nospam.invalid> wrote
> >>>>>>> Rod Speed <rod.speed.aaa@gmail.com> wrote
> 
> >>>>>>>>>> I remember using an external DVD-ROM drive that
> >>>>>>>>>> used two USB connections that didn't use power AC.
> 
> >>>>>>>>> that's a gross hack.
> 
> >>>>>>>> Its no different to using an external wall
> >>>>>>>> wart, much more convenient to use.
> 
> >>>>>>> it's completely different.
> 
> >>>>>> Bullshit.
> 
> >>>>>>> nobody would think of plugging an appliance
> >>>>>>> into two outlets to get 30 amps instead of 15.
> 
> >>>>>> USB is different, stupid.
> 
> >>>>> Actually, no.
> 
> >>>> Fraid so.
> 
> >>>>> Using a pair of USB ports *on the same device* is a perfectly
> >>>>> legitimate way to get more current than one port will deliver.
> 
> >>>> Sure, but is nothing like plugging an appliance
> >>>> into two outlets to geet 30 amps instead of 15.
> 
> >>> And as I said, I've done that and it works just fine.
> 
> >> You haven't, actually. There are no appliances that
> >> need 30 amps that plug into a normal outlet that
> >> wont work when plugged into just one and do
> >> work when plugged into two at the same time.
> 
> > Not ones you buy in a store. Do you ever build things for yourself? I do.
> 
> Yep, been doing that since before you were even born,
> and built and wired my entire house as well, and powered
> the entire house from the builder's temporary supply for
> quite a while until the supply authority eventually chucked
> a wobbly and demanded I connect the house properly.
> 
> >>>>> Currents just add.
> 
> >>>> Fraid not.
> 
> >>> well, Herr Kirchhoff sure thought so in about
> >>> 1845, and every electrical engineer since his
> >>> time has depended on it being true,
> 
> >> Not in the that situation where you have an appliance
> >> that is plugged into two outlets at the same time.
> 
> >>> but YMMV ...
> 
> >>> If you have an ammeter, you could try it using the USB ports
> >>> on your computer. If you did, I'm fraid you'd be surprised.
> 
> >> I didn1t say it isnt true with the USB ports, it clearly is.
> 
> >> I was talking about your other appliance claim where it isnt.
> >> You don1t see the appliance taking 15 amps when plugged
> >> into one outlet and 30 amps when plugged into two outlets.
> >> It takes the same total current in both situations, because the
> >> current taken is determined by V=IR.
> 
> > It's pretty clear that the item drawing current has to be able to
> > draw more than 15 Amps for the two-outlet trick to be of any use.
> 
> And there arent any appliances like that.
> 
> > IOW, you need to have a load that would
> > draw more than 15 Amps. at local line voltage.
> 
> And there arent any appliances like that.
> 
> > In fact, what I built that worked that way was a portable light board
> > for in-the-round theater productions. 15 Amps couldn't handle enough
> > lights, but 30 Amps (from two outlets on different breakers) could.
> 
> That's not an appliance.
> 
> >> Its different with USB when the USB port is current limited.
> 
> > If a USB port's source ability is limited to, say, 0.5 Amps, then
> > combining two of them you can get pretty close to a full amp
> > (depends on how well the two hook-ups are balanced).
> 
> Yes, but the mains doesn�t work like that.

OK, I'll bite. In precisely what way is "the mains" different from every 
other sort of electrical circuit that makes your claim correct (i.e. 
that you can't draw more current from two *independently fused* circuits 
than you can get from a single one)?

Isaac
0
isw
8/27/2014 5:05:20 AM
In the last episode of <c6557sF8ub5U1@mid.individual.net>, Jolly Roger
<jollyroger@pobox.com> said:

>["Followup-To:" header set to comp.sys.mac.hardware.storage.]

[Fixed that]

>
>On 2014-08-27, DevilsPGD <boogabooga@crazyhat.net> wrote:
>
>> In the last episode of <isw-4FAF80.09163626082014@[216.168.3.50]>, isw
>><isw@witzend.com> said:
>
>> There's no reason that the OS need be involved, the drive could shut
>> down until either the impact or the free-fall event is over, from the OS
>> this isn't any different than a drive which pauses to attempt a repair
>> of a particular sector.
>
>That's assuming the sensor is built into the hard drive itself. Not all
>hard drives have such sensors. Without such a sensor, the drive is
>effectively blind to the tragedy that is about to happen, and therefore
>can't react. That's where Apple's sudden motion sensor comes into play: 
>
><http://support.apple.com/kb/HT1935>

Sure. But making the drive itself aware is a better solution since it
doesn't rely upon the computer to have particular hardware, the OS to be
functioning and the driver installed, whereas a solution built into the
drive will work all the time, every time.

Still, for most practical purposes, the difference is probably
interchangeable, at least until you initiate hibernate or shutdown, pick
up your laptop to walk off and drop it in those few moments between when
sensor driver unloads and when the drive itself shuts down.
Unfortunately this is a fairly likely time to drop a laptop, since it's
a likely time for you to be moving it.

The right implementation could, of course, ensure that this driver isn't
unloaded until the drive is powered down, but this would require a
kernel level implementation, and again, is OS specific whereas
implementing it in the drive will work regardless of the OS the user
chooses to use.

-- 
What's the difference between ignorance and apathy?
I don't know and I don't care.
0
DevilsPGD
8/27/2014 7:39:00 AM
In the last episode of <isw-731339.22052026082014@[216.168.3.50]>, isw
<isw@witzend.com> said:

>In article <c648aqF3ce1U1@mid.individual.net>,
> "Rod Speed" <rod.speed.aaa@gmail.com> wrote:
>
>> isw <isw@witzend.com> wrote
>> > Rod Speed <rod.speed.aaa@gmail.com> wrote
>> >> isw <isw@witzend.com> wrote
>> >>> Rod Speed <rod.speed.aaa@gmail.com> wrote
>> >>>> isw <isw@witzend.com> wrote
>> >>>>> Rod Speed <rod.speed.aaa@gmail.com> wrote
>> >>>>>> nospam <nospam@nospam.invalid> wrote
>> >>>>>>> Rod Speed <rod.speed.aaa@gmail.com> wrote
>> 
>> >>>>>>>>>> I remember using an external DVD-ROM drive that
>> >>>>>>>>>> used two USB connections that didn't use power AC.
>> 
>> >>>>>>>>> that's a gross hack.
>> 
>> >>>>>>>> Its no different to using an external wall
>> >>>>>>>> wart, much more convenient to use.
>> 
>> >>>>>>> it's completely different.
>> 
>> >>>>>> Bullshit.
>> 
>> >>>>>>> nobody would think of plugging an appliance
>> >>>>>>> into two outlets to get 30 amps instead of 15.
>> 
>> >>>>>> USB is different, stupid.
>> 
>> >>>>> Actually, no.
>> 
>> >>>> Fraid so.
>> 
>> >>>>> Using a pair of USB ports *on the same device* is a perfectly
>> >>>>> legitimate way to get more current than one port will deliver.
>> 
>> >>>> Sure, but is nothing like plugging an appliance
>> >>>> into two outlets to geet 30 amps instead of 15.
>> 
>> >>> And as I said, I've done that and it works just fine.
>> 
>> >> You haven't, actually. There are no appliances that
>> >> need 30 amps that plug into a normal outlet that
>> >> wont work when plugged into just one and do
>> >> work when plugged into two at the same time.
>> 
>> > Not ones you buy in a store. Do you ever build things for yourself? I do.
>> 
>> Yep, been doing that since before you were even born,
>> and built and wired my entire house as well, and powered
>> the entire house from the builder's temporary supply for
>> quite a while until the supply authority eventually chucked
>> a wobbly and demanded I connect the house properly.
>> 
>> >>>>> Currents just add.
>> 
>> >>>> Fraid not.
>> 
>> >>> well, Herr Kirchhoff sure thought so in about
>> >>> 1845, and every electrical engineer since his
>> >>> time has depended on it being true,
>> 
>> >> Not in the that situation where you have an appliance
>> >> that is plugged into two outlets at the same time.
>> 
>> >>> but YMMV ...
>> 
>> >>> If you have an ammeter, you could try it using the USB ports
>> >>> on your computer. If you did, I'm fraid you'd be surprised.
>> 
>> >> I didn1t say it isnt true with the USB ports, it clearly is.
>> 
>> >> I was talking about your other appliance claim where it isnt.
>> >> You don1t see the appliance taking 15 amps when plugged
>> >> into one outlet and 30 amps when plugged into two outlets.
>> >> It takes the same total current in both situations, because the
>> >> current taken is determined by V=IR.
>> 
>> > It's pretty clear that the item drawing current has to be able to
>> > draw more than 15 Amps for the two-outlet trick to be of any use.
>> 
>> And there arent any appliances like that.
>> 
>> > IOW, you need to have a load that would
>> > draw more than 15 Amps. at local line voltage.
>> 
>> And there arent any appliances like that.
>> 
>> > In fact, what I built that worked that way was a portable light board
>> > for in-the-round theater productions. 15 Amps couldn't handle enough
>> > lights, but 30 Amps (from two outlets on different breakers) could.
>> 
>> That's not an appliance.
>> 
>> >> Its different with USB when the USB port is current limited.
>> 
>> > If a USB port's source ability is limited to, say, 0.5 Amps, then
>> > combining two of them you can get pretty close to a full amp
>> > (depends on how well the two hook-ups are balanced).
>> 
>> Yes, but the mains doesn�t work like that.
>
>OK, I'll bite. In precisely what way is "the mains" different from every 
>other sort of electrical circuit that makes your claim correct (i.e. 
>that you can't draw more current from two *independently fused* circuits 
>than you can get from a single one)?

And (to the previous poster), consider in your answer that we do have
appliances almost like this: Dryers and stoves in North America
typically (although not exclusively) use a 240V 30A circuit which is
actually two 120V 15A circuits (in a split-phase configuration).

In defense of how "the mains" is different, there actually is a
difference: AC vs DC current. With AC current you have to consider what
happens if your sources are in phase or not, as it's possible for
different circuits to be 180 degrees out of phase, or on completely
different cycles (when a set of UPSes or generators may kick in)

DC is much simpler in this respect, giving use simple USB circuits that
draw from multiple ports without requiring explicit design on the part
of the supply, or complicated transformer designs on the appliance.

But ultimately, at it's most basic level, North American 240V appliances
are quite similar in concept (if not in design) as they use two
independently fused circuits -- Oh yeah, and the circuit breakers are
usually linked so that tripping one trips the other. Since this is done
mechanically and not electrically, they're still independent fuses from
an electrical standpoint.

-- 
What's the difference between ignorance and apathy?
I don't know and I don't care.
0
DevilsPGD
8/27/2014 7:39:00 AM
On 8/26/2014 1:18 PM PT, VanguardLH typed:
> So after all the suggestions in the other responses that are based on
> unknown hardware, what port types are actually available in your present
> computer?  Or was this just an curiosity inquiry to possibly affect on
> what you might include in a later build?

It was just a curiosity inquiry for the future of portable HDD 
purchases. I really like the tiny portable HDDs that don't need the 
annoying power bricks and its cable, but I read that they had power 
problems. Big enclosures can have extra goodies like ESATA, Firewire, 
Thunderbolt, better cooling, etc. So I was wondering if enclosures 
existed like that.
-- 
"When you need a helpline for breakfast cereals, it's time to start 
thinking about tearing down civilization and giving the ants a go." 
--Chris King in a.s.r.
    /\___/\         Ant(Dude) @ http://antfarm.ma.cx (Personal Web Site)
   / /\ /\ \                Ant's Quality Foraged Links: http://aqfl.net
  | |o   o| |
     \ _ /        If crediting, then use Ant nickname and AQFL URL/link.
      ( )         If e-mailing, then axe ANT from its address if needed.
Ant is currently not listening to any songs on this computer.
0
Ant
8/27/2014 8:22:39 AM
On 2014-08-27, DevilsPGD <boogabooga@crazyhat.net> wrote:
> In the last episode of <c6557sF8ub5U1@mid.individual.net>, Jolly Roger
><jollyroger@pobox.com> said:
>
>>On 2014-08-27, DevilsPGD <boogabooga@crazyhat.net> wrote:
>>
>>> In the last episode of <isw-4FAF80.09163626082014@[216.168.3.50]>, isw
>>><isw@witzend.com> said:
>>
>>> There's no reason that the OS need be involved, the drive could shut
>>> down until either the impact or the free-fall event is over, from the OS
>>> this isn't any different than a drive which pauses to attempt a repair
>>> of a particular sector.
>>
>>That's assuming the sensor is built into the hard drive itself. Not all
>>hard drives have such sensors. Without such a sensor, the drive is
>>effectively blind to the tragedy that is about to happen, and therefore
>>can't react. That's where Apple's sudden motion sensor comes into play: 
>>
>><http://support.apple.com/kb/HT1935>
>
> Sure. But making the drive itself aware is a better solution since it
> doesn't rely upon the computer to have particular hardware, the OS to be
> functioning and the driver installed, whereas a solution built into the
> drive will work all the time, every time.

That doesn't change the fact that most drives have no such hardware
built-in, probably to reduce costs. Those who want a drive that has it
built in, then go find and probably pay more for one.

-- 
E-mail sent to this address may be devoured by my ravenous SPAM filter.
I often ignore posts from Google. Use a real news client instead.

JR
0
Jolly
8/27/2014 5:33:24 PM
isw <isw@witzend.com> wrote
> Rod Speed <rod.speed.aaa@gmail.com> wrote
>> isw <isw@witzend.com> wrote
>>> Rod Speed <rod.speed.aaa@gmail.com> wrote
>>>> isw <isw@witzend.com> wrote
>>>>> Rod Speed <rod.speed.aaa@gmail.com> wrote
>>>>>> isw <isw@witzend.com> wrote
>>>>>>> Rod Speed <rod.speed.aaa@gmail.com> wrote
>>>>>>>> nospam <nospam@nospam.invalid> wrote
>>>>>>>>> Rod Speed <rod.speed.aaa@gmail.com> wrote

>>>>>>>>>>>> I remember using an external DVD-ROM drive that
>>>>>>>>>>>> used two USB connections that didn't use power AC.

>>>>>>>>>>> that's a gross hack.

>>>>>>>>>> Its no different to using an external wall
>>>>>>>>>> wart, much more convenient to use.

>>>>>>>>> it's completely different.

>>>>>>>> Bullshit.

>>>>>>>>> nobody would think of plugging an appliance
>>>>>>>>> into two outlets to get 30 amps instead of 15.

>>>>>>>> USB is different, stupid.

>>>>>>> Actually, no.

>>>>>> Fraid so.

>>>>>>> Using a pair of USB ports *on the same device* is a perfectly
>>>>>>> legitimate way to get more current than one port will deliver.

>>>>>> Sure, but is nothing like plugging an appliance
>>>>>> into two outlets to geet 30 amps instead of 15.

>>>>> And as I said, I've done that and it works just fine.

>>>> You haven't, actually. There are no appliances that
>>>> need 30 amps that plug into a normal outlet that
>>>> wont work when plugged into just one and do
>>>> work when plugged into two at the same time.

>>> Not ones you buy in a store. Do you ever build things for yourself? I 
>>> do.

>> Yep, been doing that since before you were even born,
>> and built and wired my entire house as well, and powered
>> the entire house from the builder's temporary supply for
>> quite a while until the supply authority eventually chucked
>> a wobbly and demanded I connect the house properly.

>>>>>>> Currents just add.

>>>>>> Fraid not.

>>>>> well, Herr Kirchhoff sure thought so in about
>>>>> 1845, and every electrical engineer since his
>>>>> time has depended on it being true,

>>>> Not in the that situation where you have an appliance
>>>> that is plugged into two outlets at the same time.

>>>>> but YMMV ...

>>>>> If you have an ammeter, you could try it using the USB ports
>>>>> on your computer. If you did, I'm fraid you'd be surprised.

>>>> I didn1t say it isnt true with the USB ports, it clearly is.

>>>> I was talking about your other appliance claim where it isnt.
>>>> You don1t see the appliance taking 15 amps when plugged
>>>> into one outlet and 30 amps when plugged into two outlets.
>>>> It takes the same total current in both situations, because the
>>>> current taken is determined by V=IR.

>>> It's pretty clear that the item drawing current has to be able to
>>> draw more than 15 Amps for the two-outlet trick to be of any use.

>> And there arent any appliances like that.

>>> IOW, you need to have a load that would
>>> draw more than 15 Amps. at local line voltage.

>> And there arent any appliances like that.

>>> In fact, what I built that worked that way was a portable light board
>>> for in-the-round theater productions. 15 Amps couldn't handle enough
>>> lights, but 30 Amps (from two outlets on different breakers) could.

>> That's not an appliance.

>>>> Its different with USB when the USB port is current limited.

>>> If a USB port's source ability is limited to, say, 0.5 Amps, then
>>> combining two of them you can get pretty close to a full amp
>>> (depends on how well the two hook-ups are balanced).

>> Yes, but the mains doesn�t work like that.

> OK, I'll bite.

There is no bait.

> In precisely what way is "the mains" different from every
> other sort of electrical circuit that makes your claim correct
> (i.e. that you can't draw more current from two *independently
> fused* circuits than you can get from a single one)?

The mains sockets have a completely different
fuse/breaker arrangement than USB ports do.

If the problem with running your imaginary 30A appliance
from a single outlet is that the breaker trips when you turn
the appliance on when its plugged into a single 15A socket,
plugging it into two 15A sockets that have a single breaker
wont achieve a damned thing. If each 15A socket has its
own breaker, that will work fine, but has nothing to do
with your line about currents being additive, what matters
is how the breaker is done.

And USB ports work very differently. They don�t have
breakers that are relevant to the situation being discussed,
they just limit the current that can be drawn, so using two
works fine because both continue to supply what they
can supply. Nothing like with the mains non existent
30A appliance. 

0
Rod
8/27/2014 9:07:00 PM

"DevilsPGD" <boogabooga@crazyhat.net> wrote in message 
news:8b1rv954jeo8biqohhkdio9c3s3m2uaj4a@4ax.com...
> In the last episode of <isw-731339.22052026082014@[216.168.3.50]>, isw
> <isw@witzend.com> said:
>
>>In article <c648aqF3ce1U1@mid.individual.net>,
>> "Rod Speed" <rod.speed.aaa@gmail.com> wrote:
>>
>>> isw <isw@witzend.com> wrote
>>> > Rod Speed <rod.speed.aaa@gmail.com> wrote
>>> >> isw <isw@witzend.com> wrote
>>> >>> Rod Speed <rod.speed.aaa@gmail.com> wrote
>>> >>>> isw <isw@witzend.com> wrote
>>> >>>>> Rod Speed <rod.speed.aaa@gmail.com> wrote
>>> >>>>>> nospam <nospam@nospam.invalid> wrote
>>> >>>>>>> Rod Speed <rod.speed.aaa@gmail.com> wrote
>>>
>>> >>>>>>>>>> I remember using an external DVD-ROM drive that
>>> >>>>>>>>>> used two USB connections that didn't use power AC.
>>>
>>> >>>>>>>>> that's a gross hack.
>>>
>>> >>>>>>>> Its no different to using an external wall
>>> >>>>>>>> wart, much more convenient to use.
>>>
>>> >>>>>>> it's completely different.
>>>
>>> >>>>>> Bullshit.
>>>
>>> >>>>>>> nobody would think of plugging an appliance
>>> >>>>>>> into two outlets to get 30 amps instead of 15.
>>>
>>> >>>>>> USB is different, stupid.
>>>
>>> >>>>> Actually, no.
>>>
>>> >>>> Fraid so.
>>>
>>> >>>>> Using a pair of USB ports *on the same device* is a perfectly
>>> >>>>> legitimate way to get more current than one port will deliver.
>>>
>>> >>>> Sure, but is nothing like plugging an appliance
>>> >>>> into two outlets to geet 30 amps instead of 15.
>>>
>>> >>> And as I said, I've done that and it works just fine.
>>>
>>> >> You haven't, actually. There are no appliances that
>>> >> need 30 amps that plug into a normal outlet that
>>> >> wont work when plugged into just one and do
>>> >> work when plugged into two at the same time.
>>>
>>> > Not ones you buy in a store. Do you ever build things for yourself? I 
>>> > do.
>>>
>>> Yep, been doing that since before you were even born,
>>> and built and wired my entire house as well, and powered
>>> the entire house from the builder's temporary supply for
>>> quite a while until the supply authority eventually chucked
>>> a wobbly and demanded I connect the house properly.
>>>
>>> >>>>> Currents just add.
>>>
>>> >>>> Fraid not.
>>>
>>> >>> well, Herr Kirchhoff sure thought so in about
>>> >>> 1845, and every electrical engineer since his
>>> >>> time has depended on it being true,
>>>
>>> >> Not in the that situation where you have an appliance
>>> >> that is plugged into two outlets at the same time.
>>>
>>> >>> but YMMV ...
>>>
>>> >>> If you have an ammeter, you could try it using the USB ports
>>> >>> on your computer. If you did, I'm fraid you'd be surprised.
>>>
>>> >> I didn1t say it isnt true with the USB ports, it clearly is.
>>>
>>> >> I was talking about your other appliance claim where it isnt.
>>> >> You don1t see the appliance taking 15 amps when plugged
>>> >> into one outlet and 30 amps when plugged into two outlets.
>>> >> It takes the same total current in both situations, because the
>>> >> current taken is determined by V=IR.
>>>
>>> > It's pretty clear that the item drawing current has to be able to
>>> > draw more than 15 Amps for the two-outlet trick to be of any use.
>>>
>>> And there arent any appliances like that.
>>>
>>> > IOW, you need to have a load that would
>>> > draw more than 15 Amps. at local line voltage.
>>>
>>> And there arent any appliances like that.
>>>
>>> > In fact, what I built that worked that way was a portable light board
>>> > for in-the-round theater productions. 15 Amps couldn't handle enough
>>> > lights, but 30 Amps (from two outlets on different breakers) could.
>>>
>>> That's not an appliance.
>>>
>>> >> Its different with USB when the USB port is current limited.
>>>
>>> > If a USB port's source ability is limited to, say, 0.5 Amps, then
>>> > combining two of them you can get pretty close to a full amp
>>> > (depends on how well the two hook-ups are balanced).
>>>
>>> Yes, but the mains doesn�t work like that.
>>
>>OK, I'll bite. In precisely what way is "the mains" different from every
>>other sort of electrical circuit that makes your claim correct (i.e.
>>that you can't draw more current from two *independently fused* circuits
>>than you can get from a single one)?

> And (to the previous poster), consider in your answer
> that we do have appliances almost like this:

No, nothing like this.

> Dryers and stoves in North America typically (although
> not exclusively) use a 240V 30A circuit which is actually
> two 120V 15A circuits (in a split-phase configuration).

And that is nothing like what he was talking about which
is plugging the non existent 120V 30A appliance into two
outlets. Yours is a 240V 30A appliance, a different matter
entirely.

> In defense of how "the mains" is different,
> there actually is a difference: AC vs DC current.

That isnt relevant to what is being discussed because
he isnt talking about a 240V 30A appliance, he's talking
about a non existent 120V 30A appliance.

> With AC current you have to consider what happens if your
> sources are in phase or not, as it's possible for different
> circuits to be 180 degrees out of phase, or on completely
> different cycles (when a set of UPSes or generators may kick in)

> DC is much simpler in this respect, giving use simple USB circuits that
> draw from multiple ports without requiring explicit design on the part
> of the supply, or complicated transformer designs on the appliance.

> But ultimately, at it's most basic level, North American 240V appliances
> are quite similar in concept (if not in design) as they use two
> independently fused circuits -- Oh yeah, and the circuit breakers are
> usually linked so that tripping one trips the other. Since this is done
> mechanically and not electrically, they're still independent fuses from
> an electrical standpoint.

But that isnt the 120V 30A non existent appliance being discussed. 

0
Rod
8/27/2014 9:12:32 PM
isw <isw@witzend.com> wrote
> Rod Speed <rod.speed.aaa@gmail.com> wrote
>> isw <isw@witzend.com> wrote
>>> Rod Speed <rod.speed.aaa@gmail.com> wrote
>>>> isw <isw@witzend.com> wrote
>>>>> Rod Speed <rod.speed.aaa@gmail.com> wrote
>>>>>> isw <isw@witzend.com> wrote
>>>>>>> Rod Speed <rod.speed.aaa@gmail.com> wrote
>>>>>>>> nospam <nospam@nospam.invalid> wrote
>>>>>>>>> Rod Speed <rod.speed.aaa@gmail.com> wrote

>>>>>>>>>>>>> I know some people prefer to use portable external
>>>>>>>>>>>>> HDDs, with their power AC connection enclosures
>>>>>>>>>>>>> or adapters, for reliability and stability.

>>>>>>>>>>>> That's mad. By definition external HDDs are less reliable than
>>>>>>>>>>>> internal drives just because they are easier to drop and knock
>>>>>>>>>>>> over and because they don1t have as good cooling as you can
>>>>>>>>>>>> easily achieve with an internal drive in a decent case.

>>>>>>>>>>> don't drop them and they're just as reliable.

>>>>>>>>>> No, because they are MUCH easier to bump when using them.

>>>>>>>>> only for klutzes.

>>>>>>>> Bullshit. There are plenty who arent klutzes that don't
>>>>>>>> even realise that there is a spinning disk in an external
>>>>>>>> hard drive with the heads flying over the surface and
>>>>>>>> gyroscopic effects.

>>>>>>> Although you can feel the gyro effect if you tilt the drive while 
>>>>>>> it's
>>>>>>> spinning, what is the effect *inside it* that can cause a problem?

>>>>>> You can end up with a head crash.

>>>>> Well, yes, but that's nearly the only mechanical
>>>>> problem an operating disk can have.

>>>> That's not right, you can get bearing failure too.

>>>>> What I'm asking is, what about the gyroscopic
>>>>> effect *specifically* is it that causes the crash?

>>>> The same effect there has always been
>>>> with moving a drive when its spinning.

>>> My point exactly:

>> Nope.

>>> there is nothing at all about the gyroscopic effect
>>> that makes a disk malfunction any more likely.

>> Have fun explaining why normal desktop drives have
>> failed when the system is moved with the drives spinning.

>> And you can get quite high G loads just by letting the drive
>> down hard as you place it on the desktop when running.

> Correlation is not causation.

Even sillier than you usually manage in the situation being discussed.

> Clearly, just about the only time a modern disk can have
> a head crash is when the head is flying above the disk, and
> the only time it is doing that is when the platter is rotating.

And what matters is whether the G force caused the head to crash.

There are only two ways to get a head crash, either with a G force
or with something getting between the head and the platter and
the later cant happen with nothing loose in side the drive.

> But the issue we're discussing is the gyroscopic
> behavior of the spinning platter.

That is just one of the effects being discussed
with an external hard drive.

> Can you make a case that it is *specifically*
> the gyroscopic effect that causes the crash?
> I cannot think of any reason why it would.

Your problem.
 

0
Rod
8/27/2014 9:12:45 PM
In article <isidnfIPjdub_WfOnZ2dnUVZ_s-dnZ2d@earthlink.com>,
 Ant <ant@zimage.comANT> wrote:

> On 8/24/2014 1:44 PM PT, nospam typed:
> 
> >> Aww, so it won't matter these days for the newer stuff then. I remember
> >> using an external DVD-ROM drive that used two USB connections that
> >> didn't use power AC.
> >
> > that's a gross hack.
> 
> It is? Why is it bad? It worked when I used it at work.

Because most computers have limited USB ports and you lose the
benefit of USB power if you have to use a powered hub.-

One for an external disk, one for a USB DAC, one for a keyboard, and 
one for a mouse and I'm up to 4 devices already.

(No point to wireless keyboard and mouse, I'd have to chain them to 
the confuser anyway so I could find them.

-- 
Never attribute to stupidity that which can be explained by greed. Me.
0
Walter
10/5/2014 12:23:14 PM
Reply: