f



Good source for "new" 5.25 and 3.5 inch floppy disks?

All,

Well, I made up some disks for someone recently, and I was forced to
open my last box of blank 5.25 inch floppies. Uh Oh.

It then occurred to me that my supply of Double Density 3.5 inch disks
is all down to old PC disks, about half of which test bad when I
format them.

Ditto for the High Density 3.5 inch disks for my SuperDrives, which
also test bad about half the time.

So really, what it seems I need is fresh supply of floppy disks, but
are there such things any more? I see folks selling them on ebay, and
Google turned up a few places (such as http://www.oldsoftware.com/disks.html)
that seem to have some supply, but perhaps my fellow CSA2-ers can
recommend a place that has sold them consistently good media at a good
price.

And are truly new, quality, double-density 5.25 and 3.5 inch disks
even sold anymore?

Thanks,
Warr

0
wernst (378)
9/17/2007 6:40:02 PM
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On Sep 17, 2:40 pm, Warren Ernst <wer...@gmail.com> wrote:
> And are truly new, quality, double-density 5.25 and 3.5 inch disks
> even sold anymore?
Two places I've seen:
http://floppydisk.com/
http://athana.com/


0
schmidtd (1096)
9/17/2007 7:11:42 PM


On 9/17/07 2:40 PM, in article
1190054402.084122.307600@k79g2000hse.googlegroups.com, "Warren Ernst"
<wernst@gmail.com> wrote:

> All,
> 
> Well, I made up some disks for someone recently, and I was forced to
> open my last box of blank 5.25 inch floppies. Uh Oh.
> 
> It then occurred to me that my supply of Double Density 3.5 inch disks
> is all down to old PC disks, about half of which test bad when I
> format them.
> 
> Ditto for the High Density 3.5 inch disks for my SuperDrives, which
> also test bad about half the time.
> 
> So really, what it seems I need is fresh supply of floppy disks, but
> are there such things any more? I see folks selling them on ebay, and
> Google turned up a few places (such as http://www.oldsoftware.com/disks.html)
> that seem to have some supply, but perhaps my fellow CSA2-ers can
> recommend a place that has sold them consistently good media at a good
> price.
> 
> And are truly new, quality, double-density 5.25 and 3.5 inch disks
> even sold anymore?

I've seen 3.5" disks at Wal-Mart and Big Lots, new in the box.
I wouldn't bet on the quality though. Reports have been that quality of
floppies have dropped since they are no longer the media of choice.


0
bjjlyates1 (56)
9/17/2007 8:30:17 PM
On Sep 17, 1:30 pm, winston19842005 <bjjlya...@bellsouth.net> wrote:
> On 9/17/07 2:40 PM, in article
> 1190054402.084122.307...@k79g2000hse.googlegroups.com, "Warren Ernst"
>
>
>
> <wer...@gmail.com> wrote:
> > All,
>
> > Well, I made up some disks for someone recently, and I was forced to
> > open my last box of blank 5.25 inch floppies. Uh Oh.
>
> > It then occurred to me that my supply of Double Density 3.5 inch disks
> > is all down to old PC disks, about half of which test bad when I
> > format them.
>
> > Ditto for the High Density 3.5 inch disks for my SuperDrives, which
> > also test bad about half the time.
>
> > So really, what it seems I need is fresh supply of floppy disks, but
> > are there such things any more? I see folks selling them on ebay, and
> > Google turned up a few places (such ashttp://www.oldsoftware.com/disks.html)
> > that seem to have some supply, but perhaps my fellow CSA2-ers can
> > recommend a place that has sold them consistently good media at a good
> > price.
>
> > And are truly new, quality, double-density 5.25 and 3.5 inch disks
> > even sold anymore?
>
> I've seen 3.5" disks at Wal-Mart and Big Lots, new in the box.
> I wouldn't bet on the quality though. Reports have been that quality of
> floppies have dropped since they are no longer the media of choice.

WalMart and other office supply stores sell *high density* disks.
Though you can use such disks in a pinch (I'm told), what I'm looking
for is 800k double-density disks.

-Warr

0
wernst (378)
9/17/2007 8:40:58 PM


On 9/17/07 4:40 PM, in article
1190061658.713269.153530@d55g2000hsg.googlegroups.com, "Warren Ernst"
<wernst@gmail.com> wrote:

> On Sep 17, 1:30 pm, winston19842005 <bjjlya...@bellsouth.net> wrote:
>> On 9/17/07 2:40 PM, in article
>> 1190054402.084122.307...@k79g2000hse.googlegroups.com, "Warren Ernst"
>> 
>> 
>> 
>> <wer...@gmail.com> wrote:
>>> All,
>> 
>>> Well, I made up some disks for someone recently, and I was forced to
>>> open my last box of blank 5.25 inch floppies. Uh Oh.
>> 
>>> It then occurred to me that my supply of Double Density 3.5 inch disks
>>> is all down to old PC disks, about half of which test bad when I
>>> format them.
>> 
>>> Ditto for the High Density 3.5 inch disks for my SuperDrives, which
>>> also test bad about half the time.
>> 
>>> So really, what it seems I need is fresh supply of floppy disks, but
>>> are there such things any more? I see folks selling them on ebay, and
>>> Google turned up a few places (such ashttp://www.oldsoftware.com/disks.html)
>>> that seem to have some supply, but perhaps my fellow CSA2-ers can
>>> recommend a place that has sold them consistently good media at a good
>>> price.
>> 
>>> And are truly new, quality, double-density 5.25 and 3.5 inch disks
>>> even sold anymore?
>> 
>> I've seen 3.5" disks at Wal-Mart and Big Lots, new in the box.
>> I wouldn't bet on the quality though. Reports have been that quality of
>> floppies have dropped since they are no longer the media of choice.
> 
> WalMart and other office supply stores sell *high density* disks.
> Though you can use such disks in a pinch (I'm told), what I'm looking
> for is 800k double-density disks.

Well, we Tiers use them all the time in our 720k drives, just tape over the
density hole.

There are more than enough threads arguing about media differences, but IMHO
those only applied to the 5.25" HD media (and I keep finding a pack or two
of those after all these years unopened to throw out).

As for quality, I would suggest reading the disk tests of Paul Panks over on
comp.sys.cbm. Especially if you need a laugh... ;)

0
bjjlyates1 (56)
9/17/2007 9:19:30 PM
winston19842005 wrote:
> 
>> WalMart and other office supply stores sell *high density* disks.
>> Though you can use such disks in a pinch (I'm told), what I'm looking
>> for is 800k double-density disks.
> 
> Well, we Tiers use them all the time in our 720k drives, just tape over the
> density hole.

You must enjoy data loss, then.  The heads on low density drives cannot 
generate a field sufficient to fully saturate domains on the media.  Don't bet 
the farm on being able to read those disks back after a few years.

I'm starting to find that most "low" (DD) density 3.5" diskettes are bad out 
of the box.  Whenever I need to use them with either my Apples or Amigas, I 
end up throwing out 3 of 5 for format/verify errors.  I'd like to think that 
it's bad drives, but I have a pile of them and the bad disks are well and 
truly... bad.

Steve
0
snhirsch (1237)
9/18/2007 11:53:15 AM


On 9/18/07 7:53 AM, in article
zOKdne9oWf62IXLbnZ2dnUVZ_uiknZ2d@giganews.com, "Steven Hirsch"
<snhirsch@gmail.com> wrote:

> winston19842005 wrote:
>> 
>>> WalMart and other office supply stores sell *high density* disks.
>>> Though you can use such disks in a pinch (I'm told), what I'm looking
>>> for is 800k double-density disks.
>> 
>> Well, we Tiers use them all the time in our 720k drives, just tape over the
>> density hole.
> 
> You must enjoy data loss, then.  The heads on low density drives cannot
> generate a field sufficient to fully saturate domains on the media.  Don't bet
> the farm on being able to read those disks back after a few years.

Sorry, you are confusing HD 5.25" with 3.5" HD (here we go again, <sigh>!).
Besides, in my case I AM using an HD 3.5" drive, just in LD mode...

> 
> I'm starting to find that most "low" (DD) density 3.5" diskettes are bad out
> of the box.  Whenever I need to use them with either my Apples or Amigas, I
> end up throwing out 3 of 5 for format/verify errors.  I'd like to think that
> it's bad drives, but I have a pile of them and the bad disks are well and
> truly... bad.

Yes, I did mention quality of new disks was low...

0
bjjlyates1 (56)
9/18/2007 4:30:41 PM
winston19842005 wrote:

(snip)

> Sorry, you are confusing HD 5.25" with 3.5" HD (here we go again, <sigh>!).
> Besides, in my case I AM using an HD 3.5" drive, just in LD mode...

I believe that HD 3.5" drives switch write current based on the
opening indicating an HD disk.  I think that will let you write non-HD
data on them.  I don't know that it would be readable on an LD drive.

For 5.25" drives, the write current is selected by pin 2, set by the
controller based on what it thinks it is writing.  You would have
to change the signal into pin 2 to write LD data on HD disks.

-- glen

0
gah (12851)
9/18/2007 7:34:56 PM
winston19842005 wrote:
> 
> 
> On 9/18/07 7:53 AM, in article
> zOKdne9oWf62IXLbnZ2dnUVZ_uiknZ2d@giganews.com, "Steven Hirsch"
> <snhirsch@gmail.com> wrote:
> 
>> winston19842005 wrote:
>>>> WalMart and other office supply stores sell *high density* disks.
>>>> Though you can use such disks in a pinch (I'm told), what I'm looking
>>>> for is 800k double-density disks.
>>> Well, we Tiers use them all the time in our 720k drives, just tape over the
>>> density hole.
>> You must enjoy data loss, then.  The heads on low density drives cannot
>> generate a field sufficient to fully saturate domains on the media.  Don't bet
>> the farm on being able to read those disks back after a few years.
> 
> Sorry, you are confusing HD 5.25" with 3.5" HD (here we go again, <sigh>!).

Are you claiming that the coercivity specs are the same between 3.5" 
"standard" density and HD media?

> Besides, in my case I AM using an HD 3.5" drive, just in LD mode...

I genuinely am not sure of this, but doesn't the drive drop the write current 
in LD modes?  If 3.5" drives are different, can you point me to some 
documentation to confirm this?

Not trying to be argumentative, but your statements don't jive with my 
understanding and I'd like to get clear on the subject.

0
snhirsch (1237)
9/19/2007 3:36:29 PM
glen herrmannsfeldt wrote:

> winston19842005 wrote:
> 
> (snip)
> 
>> Sorry, you are confusing HD 5.25" with 3.5" HD (here we go again, 
>> <sigh>!).
>> Besides, in my case I AM using an HD 3.5" drive, just in LD mode...
> 
> 
> I believe that HD 3.5" drives switch write current based on the
> opening indicating an HD disk.  I think that will let you write non-HD
> data on them.  I don't know that it would be readable on an LD drive.
> 
> For 5.25" drives, the write current is selected by pin 2, set by the
> controller based on what it thinks it is writing.  You would have
> to change the signal into pin 2 to write LD data on HD disks.
> 
> -- glen
> 
No, high density 5.25" disks simply fail to work in my AppleDisk 5.25" 
drive. They won't format. I'm pretty sure that HD disks didn't exist 
when I got the drive, so I doubt it knows to check.
0
SlickRCBD
9/19/2007 5:34:24 PM


On 9/19/07 11:36 AM, in article
08WdnRC6XtBg3GzbnZ2dnUVZ_tGonZ2d@giganews.com, "Steven Hirsch"
<snhirsch@gmail.com> wrote:

> winston19842005 wrote:
>> 
>> 
>> On 9/18/07 7:53 AM, in article
>> zOKdne9oWf62IXLbnZ2dnUVZ_uiknZ2d@giganews.com, "Steven Hirsch"
>> <snhirsch@gmail.com> wrote:
>> 
>>> winston19842005 wrote:
>>>>> WalMart and other office supply stores sell *high density* disks.
>>>>> Though you can use such disks in a pinch (I'm told), what I'm looking
>>>>> for is 800k double-density disks.
>>>> Well, we Tiers use them all the time in our 720k drives, just tape over the
>>>> density hole.
>>> You must enjoy data loss, then.  The heads on low density drives cannot
>>> generate a field sufficient to fully saturate domains on the media.  Don't
>>> bet
>>> the farm on being able to read those disks back after a few years.
>> 
>> Sorry, you are confusing HD 5.25" with 3.5" HD (here we go again, <sigh>!).
> 
> Are you claiming that the coercivity specs are the same between 3.5"
> "standard" density and HD media?
> 
>> Besides, in my case I AM using an HD 3.5" drive, just in LD mode...
> 
> I genuinely am not sure of this, but doesn't the drive drop the write current
> in LD modes?  If 3.5" drives are different, can you point me to some
> documentation to confirm this?
> 
> Not trying to be argumentative, but your statements don't jive with my
> understanding and I'd like to get clear on the subject.
> 

No, sorry, I don't keep pointers to the Usenet threads where the relevant
documentation was - I decided to stay out of these arguments, but made the
mistake of mentioning that "they work for me" which has made this argument
rear its ugly head again - note the "sigh" above... That is regret at
bringing it up...

0
bjjlyates1 (56)
9/19/2007 6:07:47 PM
SlickRCBD wrote:

(snip, I wrote)

>> For 5.25" drives, the write current is selected by pin 2, set by the
>> controller based on what it thinks it is writing.  You would have
>> to change the signal into pin 2 to write LD data on HD disks.

> No, high density 5.25" disks simply fail to work in my AppleDisk 5.25" 
> drive. They won't format. I'm pretty sure that HD disks didn't exist 
> when I got the drive, so I doubt it knows to check.

My comment would only apply to writing DD format in HD drives that
allow that operation.  It takes more write current to write to an HD
disk, which is why it won't work in older (pre-HD) drives.

-- glen

0
gah (12851)
9/19/2007 9:08:30 PM
winston19842005 wrote:

>>>> You must enjoy data loss, then.  The heads on low density drives cannot
>>>> generate a field sufficient to fully saturate domains on the media.  Don't
>>>> bet
>>>> the farm on being able to read those disks back after a few years.

>>> Sorry, you are confusing HD 5.25" with 3.5" HD (here we go again, <sigh>!).
>> Are you claiming that the coercivity specs are the same between 3.5"
>> "standard" density and HD media?

>> Not trying to be argumentative, but your statements don't jive with my
>> understanding and I'd like to get clear on the subject.
>>
> 
> No, sorry, I don't keep pointers to the Usenet threads where the relevant
> documentation was - I decided to stay out of these arguments, but made the
> mistake of mentioning that "they work for me" which has made this argument
> rear its ugly head again - note the "sigh" above... That is regret at
> bringing it up...

Sorry to be a bother, then.
0
snhirsch (1237)
9/20/2007 12:28:48 AM
Steven Hirsch wrote:

(snip)

>> Besides, in my case I AM using an HD 3.5" drive, just in LD mode...

> I genuinely am not sure of this, but doesn't the drive drop the write 
> current in LD modes?  If 3.5" drives are different, can you point me to 
> some documentation to confirm this?

Yes, 3.5in drives are different.  For 5.25in the controller tells the
drive which density it is using, and the drive adjust the write current
appropriately.

For 3.5in the drive uses the hole (that isn't for write protect) and
adjust the write current.  If you put in a 3.5HD disk and convince
the controller to write in DD (non-HD) mode it will write DD data
using HD write current.  It should be readable on DD drives, though
I wouldn't guarantee it.

-- glen

0
gah (12851)
9/20/2007 8:26:45 AM
http://floppydisk.com/ seems to have high volume and low prices. I saw
them in the news several months back. I haven't ordered from them, so
I can't vouch for quality, but they're probably going to supply me
should I ever need a lot again (say, once I dig out my IIGS and go
hunting for disk images).

0
9/20/2007 9:15:14 PM
Miles Attacca wrote:

> http://floppydisk.com/ seems to have high volume and low prices. I saw
> them in the news several months back. I haven't ordered from them, so
> I can't vouch for quality, but they're probably going to supply me
> should I ever need a lot again (say, once I dig out my IIGS and go
> hunting for disk images).

No ED floppies, and no 8 inch floppies?

Oh well.

-- glen

0
gah (12851)
9/21/2007 12:19:32 AM
glen herrmannsfeldt wrote:
> Steven Hirsch wrote:
> 
> (snip)
> 
>>> Besides, in my case I AM using an HD 3.5" drive, just in LD mode...
> 
>> I genuinely am not sure of this, but doesn't the drive drop the write 
>> current in LD modes?  If 3.5" drives are different, can you point me 
>> to some documentation to confirm this?
> 
> Yes, 3.5in drives are different.  For 5.25in the controller tells the
> drive which density it is using, and the drive adjust the write current
> appropriately.
> 
> For 3.5in the drive uses the hole (that isn't for write protect) and
> adjust the write current.  If you put in a 3.5HD disk and convince
> the controller to write in DD (non-HD) mode it will write DD data
> using HD write current.  It should be readable on DD drives, though
> I wouldn't guarantee it.

So, my statement about DD and HD 3.5" media having different coercivity was 
correct?  That's what I thought.

0
snhirsch (1237)
9/21/2007 1:00:57 AM


On 9/20/07 9:00 PM, in article
ovOdnSyhyutUim7bnZ2dnUVZ_vXinZ2d@giganews.com, "Steven Hirsch"
<snhirsch@gmail.com> wrote:

> glen herrmannsfeldt wrote:
>> Steven Hirsch wrote:
>> 
>> (snip)
>> 
>>>> Besides, in my case I AM using an HD 3.5" drive, just in LD mode...
>> 
>>> I genuinely am not sure of this, but doesn't the drive drop the write
>>> current in LD modes?  If 3.5" drives are different, can you point me
>>> to some documentation to confirm this?
>> 
>> Yes, 3.5in drives are different.  For 5.25in the controller tells the
>> drive which density it is using, and the drive adjust the write current
>> appropriately.
>> 
>> For 3.5in the drive uses the hole (that isn't for write protect) and
>> adjust the write current.  If you put in a 3.5HD disk and convince
>> the controller to write in DD (non-HD) mode it will write DD data
>> using HD write current.  It should be readable on DD drives, though
>> I wouldn't guarantee it.
> 
> So, my statement about DD and HD 3.5" media having different coercivity was
> correct?  That's what I thought.
> 
No, coercivity was a 5.25" HD thing.

But there is the different write current to consider.

From Wikipedia on Floppy Disk:

The holes on the right side of a 31�2-inch disk can be altered as to 'fool'
some disk drives or operating systems (others such as the Acorn Archimedes
simply do not care about the holes) into treating the disk as a higher or
lower density one, for backward compatibility or economical reasons. Popular
modifications include:
Drilling or cutting an extra hole into the right-lower side of a 31�2-inch DD
disk (symmetrical to the write-protect hole) in order to format the DD disk
into a HD one. This was a popular practice during the early 1990s, as most
people switched to HD from DD during those days and some of them "converted"
some or all of their DD disks into HD ones, for gaining an extra "free" 720
kiB of disk space. The success ratio was very high, especially as late DD
disks used the same materials as HD ones, so they had no problem supporting
the higher density. In general, only very old (made before 1989) DD disks
were likely to exhibit faults and read/write errors. There even was a
special hole punch that was made to easily make this extra (square) hole in
a floppy.
Vice versa, taping the right hole on a HD 31�2-inch disk enables it to be
'downgraded' to DD format. This may sound counterproductive at first, but
there are practical scenarios, e.g. compatibility issues with older
computers, drives or devices that use DD floppies, like some electronic
keyboard instruments and samplers[53] where a 'downgraded' disk can be
useful, as factory-made DD disks have become hard to find after the
mid-1990s. See the section "Compatibility" above. It is important to note
that due to read/write voltage differences in the heads of DD vs. HD disks,
writing to an HD floppy with a DD drive (or an HD drive in DD mode) is
widely considered to be a highly unreliable method of storing data.

And then this:

Within the world of IBM-compatible computers, the three densities of 31�2-inch
floppy disks are partially compatible. Higher density drives are built to
read, write and even format lower density media without problems, provided
the correct media is used for the density selected. However, if by whatever
means a diskette is formatted at the wrong density, the result is a
substantial risk of data loss due to magnetic mismatch between oxide and the
drive head's writing attempts. Still, a fresh diskette that has been
manufactured for high density use can theoretically be formatted as double
density, but only if no information has ever been written on the disk using
high density mode (for example, HD diskettes that are pre-formatted at the
factory are out of the question). The magnetic strength of a high density
record is stronger and will "overrule" the weaker lower density, remaining
on the diskette and causing problems. However, in practice there are people
who use downformatted (ED to HD, HD to DD) or even overformatted (DD to HD)
without apparent problems; see the Floppy trivia section. Doing so always
constitutes a data risk, so one should weigh out the benefits (e.g.
increased space and/or interoperability) versus the risks (data loss,
permanent disk damage).

So, it appears there is no clear answer on the subject, at least from
Wikipedia.

I'd sure like to find a website from, say, Teac, on this subject...

0
bjjlyates1 (56)
9/21/2007 2:19:43 AM
Steven Hirsch wrote:
(snip)

> So, my statement about DD and HD 3.5" media having different coercivity 
> was correct?  That's what I thought.

I think so.

http://en.wikipedia.org/wiki/Floppy_disk_format

seems to agree.  Though the difference between DD and HD 3.5in isn't
as big as between DD and HD 5.25in, so it might be close enough.

I used to see the numbers on manufactures spec. sheets, but not
anymore.

-- glen

0
gah (12851)
9/21/2007 6:38:34 AM
winston19842005 wrote:

>>> Steven Hirsch wrote:

>> So, my statement about DD and HD 3.5" media having different coercivity was
>> correct?  That's what I thought.
>>
> No, coercivity was a 5.25" HD thing.

Actually, coercivity is a physics thing.  It's a measurable property of 
magnetic materials.  Now, whether the various types of 3.5" media differ to 
any extent and whether those differences are significant, that's another issue.

Write current is precisely the characteristic that one would adjust to best 
utilize media of a specific coercivity, since the magnetic field at the head 
is proportional to the current.

I'll have to go off and digest this stuff some more.

Steve
0
snhirsch (1237)
9/22/2007 2:10:47 AM


On 9/21/07 10:10 PM, in article
paednVf7lI465GnbnZ2dnUVZ_ramnZ2d@giganews.com, "Steven Hirsch"
<snhirsch@gmail.com> wrote:

> winston19842005 wrote:
> 
>>>> Steven Hirsch wrote:
> 
>>> So, my statement about DD and HD 3.5" media having different coercivity was
>>> correct?  That's what I thought.
>>> 
>> No, coercivity was a 5.25" HD thing.
> 
> Actually, coercivity is a physics thing.  It's a measurable property of
> magnetic materials.  Now, whether the various types of 3.5" media differ to
> any extent and whether those differences are significant, that's another
> issue.
> 
> Write current is precisely the characteristic that one would adjust to best
> utilize media of a specific coercivity, since the magnetic field at the head
> is proportional to the current.
> 
> I'll have to go off and digest this stuff some more.

The Wikipedia entry didn't seem to mention coercivity at all... And I know
for sure that was a difference in 5.25", but 3.5" is the question.

0
bjjlyates1 (56)
9/22/2007 4:08:26 AM
winston19842005 wrote:

> The Wikipedia entry didn't seem to mention coercivity at all... And I know
> for sure that was a difference in 5.25", but 3.5" is the question.

Well, Steven is right in saying that the only reason to adjust write
current is to deal with a different coercivity. I'm not a physicist, but
AFAIK there's simply no other reason why you would do it.

-- 
Linards Ticmanis
0
ticmanis (776)
9/22/2007 12:05:16 PM


On 9/22/07 8:05 AM, in article
46f504fc$0$16116$9b4e6d93@newsspool1.arcor-online.net, "Linards Ticmanis"
<ticmanis@gmx.de> wrote:

> winston19842005 wrote:
> 
>> The Wikipedia entry didn't seem to mention coercivity at all... And I know
>> for sure that was a difference in 5.25", but 3.5" is the question.
> 
> Well, Steven is right in saying that the only reason to adjust write
> current is to deal with a different coercivity. I'm not a physicist, but
> AFAIK there's simply no other reason why you would do it.

Found some info:
http://books.google.com/books?id=E1p2FDL7P5QC&pg=RA1-PA660&lpg=RA1-PA660&dq=
coercivity+on+floppy+disks&source=web&ots=M0tgBda_cz&sig=ZI_6EB1BzRzC-H85gva
9-6t5ic0#PRA1-PA660,M1

Gee, what a link - don't know what is trimmable. Here is a tinyurl:
http://tinyurl.com/yqwm85


This is a book preview that just happens to have what we want.
Go to pages 659-660...

To sum it up, you are right - there are differences (I'm tired of typing
that "C" word).

There is a table on p 659.
                                   5.25"                         3.5"
                                   DD          HD        DD         HD
Coercivity (oersteds)              300        600       600        720
Thickness of media (microns)       100         50        70         40

Just guessing, but see that the coercivity difference between the 3.5" DD
and HD is 120, vs. 5.25"'s 300 difference. And the thickness difference is
less too...

Considering the differences are less, it seems plausible to assume that
there is a better chance of data loss in the situation of 5.25" HD disks
written in an LD drive (which has been definitely what I've seen) than 3.5"
HD disks written in either an LD drive or an HD drive with the HD hole
covered on the disk (which is again what I've seen).

I guess "whatever works for you" or "play it safe and don't do it".

The book referenced is "Upgrading and Repairing PCs by Scott Mueller"...

Anybody want to update the Wiki entry on this, who has experience?

0
bjjlyates1 (56)
9/22/2007 5:01:39 PM
Steven Hirsch wrote:
(snip)

> Actually, coercivity is a physics thing.  It's a measurable property of 
> magnetic materials.  Now, whether the various types of 3.5" media differ 
> to any extent and whether those differences are significant, that's 
> another issue.

The wikipedia site I posted has it, though I didn't verify the numbers.

That site says 300 Oe and 600 Oe for 5.25in (DD and HD),
   600 Oe and 750 Oe for 3.5in (DD and HD).

For 5.25in the difference is large enough that it doesn't
seem to write at all.  For 3.5in, it might write, but not
so reliably.

-- glen

0
gah (12851)
9/22/2007 9:02:47 PM
On Sep 20, 7:19 pm, glen herrmannsfeldt <g...@ugcs.caltech.edu> wrote:
> Miles Attacca wrote:
> >http://floppydisk.com/seems to have high volume and low prices. I saw
> > them in the news several months back. I haven't ordered from them, so
> > I can't vouch for quality, but they're probably going to supply me
> > should I ever need a lot again (say, once I dig out my IIGS and go
> > hunting for disk images).
>
> No ED floppies, and no 8 inch floppies?
>
> Oh well.
>
> -- glen

Yeah, the lack of 8-inch floppies in this world rather saddens me.
Drives, too...I have an 8" (1MB?) drive in my Xerox 820-II, and no
means of copying data to or from it except once I get a terminal
connection working.

0
9/23/2007 6:13:24 AM
Miles Attacca wrote:
(snip)

> Yeah, the lack of 8-inch floppies in this world rather saddens me.
> Drives, too...I have an 8" (1MB?) drive in my Xerox 820-II, and no
> means of copying data to or from it except once I get a terminal
> connection working.


I have an 8 inch drive, but it isn't connected to anything.

I also have an 8 inch disk controller for the Apple II, but haven't
tried using it.

-- glen

0
gah (12851)
9/23/2007 9:07:39 PM
glen herrmannsfeldt wrote:
> Steven Hirsch wrote:
> (snip)
> 
>> So, my statement about DD and HD 3.5" media having different 
>> coercivity was correct?  That's what I thought.
> 
> 
> I think so.
> 
> http://en.wikipedia.org/wiki/Floppy_disk_format
> 
> seems to agree.  Though the difference between DD and HD 3.5in isn't
> as big as between DD and HD 5.25in, so it might be close enough.

Or, put another way, if your 3.5" DD drive is in any way marginal, then
it will have difficulty writing an HD disk with any permanence.

If you're not sure, and you care about the permanence of your data,
HD media in DD 3.5" drives should be avoided.

As noted before, a DD 5.25" drive will *not* reliably write HD media.

-michael

NadaPong: Network game demo for Apple II computers!
Home page:  http://members.aol.com/MJMahon/

"The wastebasket is our most important design
tool--and it's seriously underused."
0
mjmahon (7061)
9/26/2007 11:17:29 PM


On 9/27/07 9:24 AM, in article 9sidnTbAZIS0PWbbnZ2dnUVZ_qelnZ2d@comcast.com,
"glen herrmannsfeldt" <gah@ugcs.caltech.edu> wrote:

> Michael J. Mahon wrote:
> 
> (snip)
> 
>> If you're not sure, and you care about the permanence of your data,
>> HD media in DD 3.5" drives should be avoided.
> 
> As far as I understand it, it either will or won't write.
> There is a very small probability of a partial write,
> somewhat similar to a coin flip landing on the side.
> 
>> As noted before, a DD 5.25" drive will *not* reliably write HD media.
> 
> With a factor of two in coercivity for 5.25in it is pretty much
> zero chance.  Note that core memory depends on half the current not
> writing a bit for every write or read cycle.

And what really stinks is that 5.25in are hard to determine.
Just look at a 3.5", if it has a hole across from the write protect, it is
HD.

5.25in? Well, unless it is in the box, it is hard to determine (even if it
is in the box, see below). I got a shipment of new disks, no sleeves, in
plastic wrap, plus some other make that were labeled DSDD. I've found that
MANY HD 5.25" do not have hub rings. Some of these DSDD didn't have the hub
rings, and were in fact, DSHD. They would format fine in an HD drive, but
not in a regular drive.

However, I've had supposed HD disks (no hub rings from an HD box new) that
formatted great in a regular drive, but not to HD. So apparently even the
manufacturers get them mixed up.

0
bjjlyates1 (56)
9/27/2007 12:46:52 PM
Michael J. Mahon wrote:

(snip)

> If you're not sure, and you care about the permanence of your data,
> HD media in DD 3.5" drives should be avoided.

As far as I understand it, it either will or won't write.
There is a very small probability of a partial write,
somewhat similar to a coin flip landing on the side.

> As noted before, a DD 5.25" drive will *not* reliably write HD media.

With a factor of two in coercivity for 5.25in it is pretty much
zero chance.  Note that core memory depends on half the current not
writing a bit for every write or read cycle.

-- glen

0
gah (12851)
9/27/2007 1:24:22 PM
winston19842005 wrote:

(snip)

> And what really stinks is that 5.25in are hard to determine.
> Just look at a 3.5", if it has a hole across from the write protect, it is
> HD.

Some years ago I bought some of each.  To avoid this problem I bought
HD disks in blue and DD in black.

> 5.25in? Well, unless it is in the box, it is hard to determine (even if it
> is in the box, see below). I got a shipment of new disks, no sleeves, in
> plastic wrap, plus some other make that were labeled DSDD. I've found that
> MANY HD 5.25" do not have hub rings. Some of these DSDD didn't have the hub
> rings, and were in fact, DSHD. They would format fine in an HD drive, but
> not in a regular drive.

> However, I've had supposed HD disks (no hub rings from an HD box new) that
> formatted great in a regular drive, but not to HD. So apparently even the
> manufacturers get them mixed up.

When I used to use 96tpi DD disks I remember that some didn't use hub
rings because it made the disk alignment less accurate.  I don't know
that I ever believe that, but that was the reason I remember.

-- glen

0
gah (12851)
9/28/2007 2:12:33 AM
glen herrmannsfeldt wrote:
> Michael J. Mahon wrote:
> 
> (snip)
> 
>> If you're not sure, and you care about the permanence of your data,
>> HD media in DD 3.5" drives should be avoided.
> 
> 
> As far as I understand it, it either will or won't write.
> There is a very small probability of a partial write,
> somewhat similar to a coin flip landing on the side.

The coercivity specifies the field strength necessary to switch the
media from one saturated state to another.

If the media was previously recorded, then you are correct--the media,
or at least substantial parts of it, are already saturated in one or
the other direction, and write current will either be sufficient to
change it or not.

However, if the media is not recorded, or has been degaussed, then
smaller write currents will be sufficient to cause a partial response
and leave the media in a lower state of magnetization.  In this case,
the disk could read correctly for a while, but would have a lower
read signal and a lower threshold for data disturbance.

>> As noted before, a DD 5.25" drive will *not* reliably write HD media.
> 
> 
> With a factor of two in coercivity for 5.25in it is pretty much
> zero chance.  Note that core memory depends on half the current not
> writing a bit for every write or read cycle.

Excellent point!

-michael

NadaPong: Network game demo for Apple II computers!
Home page:  http://members.aol.com/MJMahon/

"The wastebasket is our most important design
tool--and it's seriously underused."
0
mjmahon (7061)
9/28/2007 9:15:41 AM
winston19842005 wrote:
> 
> 
> On 9/27/07 9:24 AM, in article 9sidnTbAZIS0PWbbnZ2dnUVZ_qelnZ2d@comcast.com,
> "glen herrmannsfeldt" <gah@ugcs.caltech.edu> wrote:
> 
> 
>>Michael J. Mahon wrote:
>>
>>(snip)
>>
>>
>>>If you're not sure, and you care about the permanence of your data,
>>>HD media in DD 3.5" drives should be avoided.
>>
>>As far as I understand it, it either will or won't write.
>>There is a very small probability of a partial write,
>>somewhat similar to a coin flip landing on the side.
>>
>>
>>>As noted before, a DD 5.25" drive will *not* reliably write HD media.
>>
>>With a factor of two in coercivity for 5.25in it is pretty much
>>zero chance.  Note that core memory depends on half the current not
>>writing a bit for every write or read cycle.
> 
> 
> And what really stinks is that 5.25in are hard to determine.
> Just look at a 3.5", if it has a hole across from the write protect, it is
> HD.
> 
> 5.25in? Well, unless it is in the box, it is hard to determine (even if it
> is in the box, see below). I got a shipment of new disks, no sleeves, in
> plastic wrap, plus some other make that were labeled DSDD. I've found that
> MANY HD 5.25" do not have hub rings. Some of these DSDD didn't have the hub
> rings, and were in fact, DSHD. They would format fine in an HD drive, but
> not in a regular drive.
> 
> However, I've had supposed HD disks (no hub rings from an HD box new) that
> formatted great in a regular drive, but not to HD. So apparently even the
> manufacturers get them mixed up.

A very good indicator (though not perfect) is that almost all 5.25" DD
coatings were brown or dark gray, while almost all HD coatings are
nearly black.

-michael

NadaPong: Network game demo for Apple II computers!
Home page:  http://members.aol.com/MJMahon/

"The wastebasket is our most important design
tool--and it's seriously underused."
0
mjmahon (7061)
9/28/2007 9:17:12 AM
I believe over the years the manufacturers, in order to boost profits,
have made the disks thinner and thinner thus lowering the
reliability.  Of course with the advent of new technologies, first the
zip disks and then flash media, there is no use for the floppy except
for us.

I just bought a copy of "The Manager" from ramito on eBay and just as
all the original disks I have from those days, they all are good.

I found a big bunch of LD 3 1/2 disks on eBay a couple of years ago.
I have just about used them all up by backing up all the software that
I have acquired.  I have found these to format fully and have not had
to throw any away.

I wouldn't use any new floppies for any thing.  I would only use HD
floppies from the late 80s if you could verify the manufacture date.

Robert


0
rtspitz (100)
9/29/2007 4:27:17 AM
golfrock wrote:
> I believe over the years the manufacturers, in order to boost profits,
> have made the disks thinner and thinner thus lowering the
> reliability.  Of course with the advent of new technologies, first the
> zip disks and then flash media, there is no use for the floppy except
> for us.

The media thickness is part of the spec, and is what keeps data
written on one side from changing data written on the other side.

One could always sacrifice an old and new disk and use a micrometer...

> I just bought a copy of "The Manager" from ramito on eBay and just as
> all the original disks I have from those days, they all are good.
> 
> I found a big bunch of LD 3 1/2 disks on eBay a couple of years ago.
> I have just about used them all up by backing up all the software that
> I have acquired.  I have found these to format fully and have not had
> to throw any away.
> 
> I wouldn't use any new floppies for any thing.  I would only use HD
> floppies from the late 80s if you could verify the manufacture date.

Maybe the problem is that there are no new floppy manufacturing
machines being made, and the old ones are getting crufty, leading
to marginal disks...

-michael

NadaPong: Network game demo for Apple II computers!
Home page:  http://members.aol.com/MJMahon/

"The wastebasket is our most important design
tool--and it's seriously underused."
0
mjmahon (7061)
9/29/2007 8:39:00 AM
Michael J. Mahon wrote:

> glen herrmannsfeldt wrote:
> 
>> Michael J. Mahon wrote:
>>
>> (snip)
>>
>>> If you're not sure, and you care about the permanence of your data,
>>> HD media in DD 3.5" drives should be avoided.
>>
>>
>>
>> As far as I understand it, it either will or won't write.
>> There is a very small probability of a partial write,
>> somewhat similar to a coin flip landing on the side.
> 
> 
> The coercivity specifies the field strength necessary to switch the
> media from one saturated state to another.
> 
> If the media was previously recorded, then you are correct--the media,
> or at least substantial parts of it, are already saturated in one or
> the other direction, and write current will either be sufficient to
> change it or not.
> 
> However, if the media is not recorded, or has been degaussed, then
> smaller write currents will be sufficient to cause a partial response
> and leave the media in a lower state of magnetization.  In this case,
> the disk could read correctly for a while, but would have a lower
> read signal and a lower threshold for data disturbance.
> 
>>> As noted before, a DD 5.25" drive will *not* reliably write HD media.
>>
>>
>>
>> With a factor of two in coercivity for 5.25in it is pretty much
>> zero chance.  Note that core memory depends on half the current not
>> writing a bit for every write or read cycle.
> 
> 
> Excellent point!
> 
> 
Just to throw my 2-cents in, My personal experience was the the 
following. Note that I never owned a 5.25" HD drive.

HD 5.25" disk in an AppleDisk 5.25" drive:
Would NOT format without errors, would not read or write data.

HD 3.5" disk in an AE 3.5" 800K drive (Replaced my AppleDisk 3.5 over a 
year before I tried a HD disk)
Formatted, but kept giving errors when I tried to use it. The disk 
formatted just fine in the computers at school, and I also tested it on 
a friend's PC.

After I finally got my hands on a SuperDrive, I tried drilling holes in 
a DD disk and formatting it as HD. It seemed to work fine, but as time 
went on I noticed that these disks seemed to have a much much higher 
rate of failure. It has been over 8 years since I've done this, and I 
don't think any of the drilled disks are still working. Of course, I've 
got a bunch I haven't tested in a while either, but none of the ones 
I've tried have worked perfectly. It seems to somehow damage the disk 
and reformatting doesn't help.

That's my non-technical, personal experience as best as I can remember 
it. It's what most people care about, what works and what doesn't. I 
should note that it took sevearl months for a DD disk formatted as HD to 
develope problems. Months of regular use, such as the data disk I used 
for my classes at school.
0
SlickRCBD
10/1/2007 7:34:19 AM
Miles Attacca wrote:

> http://floppydisk.com/ seems to have high volume and low prices. I saw
> them in the news several months back. I haven't ordered from them, so
> I can't vouch for quality, but they're probably going to supply me
> should I ever need a lot again (say, once I dig out my IIGS and go
> hunting for disk images).
> 
I just looked at the site, and I find it interesting, and ironic, that 
the DD disks cost more than the HD disks. For the entire time they were 
BOTH available in stores, the opposite was true.

I'm not sure if I want to order from them, I just wanted a 10-pack. Then 
again, I could probably split it with the person who prompted me to need 
a 10-pack. Somebody I know was just given an old Apple IIe system with 2 
5.25" drives and a monitor, but no software.

He's asked me if I can give him some software to get it going. That's 
not a problem, except that I've only got 3 blank 5.25" disks left in the 
box.

0
SlickRCBD
10/1/2007 7:43:21 AM
SlickRCBD wrote:
> Miles Attacca wrote:
> 
>> http://floppydisk.com/ seems to have high volume and low prices. I saw
>> them in the news several months back. I haven't ordered from them, so
>> I can't vouch for quality, but they're probably going to supply me
>> should I ever need a lot again (say, once I dig out my IIGS and go
>> hunting for disk images).
>>
> I just looked at the site, and I find it interesting, and ironic, that 
> the DD disks cost more than the HD disks. For the entire time they were 
> BOTH available in stores, the opposite was true.

But of course they are ***RARE***  ***CLASSIC*** !!!!  ;-)

And there are probably not too many being made any more...

-michael

NadaPong: Network game demo for Apple II computers!
Home page:  http://members.aol.com/MJMahon/

"The wastebasket is our most important design
tool--and it's seriously underused."
0
mjmahon (7061)
10/1/2007 6:58:57 PM
SlickRCBD wrote:
> Michael J. Mahon wrote:
> 
>> glen herrmannsfeldt wrote:
>>
>>> Michael J. Mahon wrote:
>>>
>>> (snip)
>>>
>>>> If you're not sure, and you care about the permanence of your data,
>>>> HD media in DD 3.5" drives should be avoided.
>>>
>>>
>>>
>>>
>>> As far as I understand it, it either will or won't write.
>>> There is a very small probability of a partial write,
>>> somewhat similar to a coin flip landing on the side.
>>
>>
>>
>> The coercivity specifies the field strength necessary to switch the
>> media from one saturated state to another.
>>
>> If the media was previously recorded, then you are correct--the media,
>> or at least substantial parts of it, are already saturated in one or
>> the other direction, and write current will either be sufficient to
>> change it or not.
>>
>> However, if the media is not recorded, or has been degaussed, then
>> smaller write currents will be sufficient to cause a partial response
>> and leave the media in a lower state of magnetization.  In this case,
>> the disk could read correctly for a while, but would have a lower
>> read signal and a lower threshold for data disturbance.
>>
>>>> As noted before, a DD 5.25" drive will *not* reliably write HD media.
>>>
>>>
>>>
>>>
>>> With a factor of two in coercivity for 5.25in it is pretty much
>>> zero chance.  Note that core memory depends on half the current not
>>> writing a bit for every write or read cycle.
>>
>>
>>
>> Excellent point!
>>
>>
> Just to throw my 2-cents in, My personal experience was the the 
> following. Note that I never owned a 5.25" HD drive.
> 
> HD 5.25" disk in an AppleDisk 5.25" drive:
> Would NOT format without errors, would not read or write data.
> 
> HD 3.5" disk in an AE 3.5" 800K drive (Replaced my AppleDisk 3.5 over a 
> year before I tried a HD disk)
> Formatted, but kept giving errors when I tried to use it. The disk 
> formatted just fine in the computers at school, and I also tested it on 
> a friend's PC.

A PC (or other HD) drive would saturate the media, but it sounds like
your AE drive was not saturating it, leaving it partially magnetized.

> After I finally got my hands on a SuperDrive, I tried drilling holes in 
> a DD disk and formatting it as HD. It seemed to work fine, but as time 
> went on I noticed that these disks seemed to have a much much higher 
> rate of failure. It has been over 8 years since I've done this, and I 
> don't think any of the drilled disks are still working. Of course, I've 
> got a bunch I haven't tested in a while either, but none of the ones 
> I've tried have worked perfectly. It seems to somehow damage the disk 
> and reformatting doesn't help.

Degaussing and reformatting would probably put you back where you
started.

> That's my non-technical, personal experience as best as I can remember 
> it. It's what most people care about, what works and what doesn't. I 
> should note that it took sevearl months for a DD disk formatted as HD to 
> develope problems. Months of regular use, such as the data disk I used 
> for my classes at school.

That's consistent with the behavior of a lower coercivity medium used
at a high density.

As the oppositely magnetized regions get closer together, they have
more tendency to "flip" adjacent regions.  Higher coercivity prevents
this (at the cost of being harder to write).

Bottom line: there's a reason for most specifications.  ;-)
(But not all--for example, after the early 1980s, virtually all
"single-sided" media were actually suitable as "double-sided".)

-michael

NadaPong: Network game demo for Apple II computers!
Home page:  http://members.aol.com/MJMahon/

"The wastebasket is our most important design
tool--and it's seriously underused."
0
mjmahon (7061)
10/1/2007 7:06:40 PM
Reply: