Do you happen to know anyone in the Long Island, New York area with a
VAX system that can read RX50's?

If needed, I can supply an RX50 dual-diskette drive and/or an Rx33
drive, as long as the system is capable of working with one or the
other to read files that were originally written to RX50 via BACKUP.

On Dec 4, 12:10=A0pm, Chris <archive.rai...@gmail.com> wrote:
> Do you happen to know anyone in the Long Island, New York area with a
> VAX system that can read RX50's?
>
> If needed, I can supply an RX50 dual-diskette drive and/or an Rx33
> drive, as long as the system is capable of working with one or the
> other to read files that were originally written to RX50 via BACKUP.

Chris,

I can blow the dust out of my RX50/RX33 drives and see if they are
still functional (they are rarely used these days).

- Bob Gezelter, http://www.rlgsc.com

Chris wrote:
> Do you happen to know anyone in the Long Island, New York area with a
> VAX system that can read RX50's?

Are RX50s, normal 3.5inch diskettes ?

I have a Vaxstation 3100 with a diskette drive that I could fire up. But
am in Montreal so diskettes would have to be sent via mail/courier.

On Dec 4, 11:10=A0am, Chris <archive.rai...@gmail.com> wrote:
> Do you happen to know anyone in the Long Island, New York area with a
> VAX system that can read RX50's?
>
> If needed, I can supply an RX50 dual-diskette drive and/or an Rx33
> drive, as long as the system is capable of working with one or the
> other to read files that were originally written to RX50 via BACKUP.

Another possible option if you can find it.  There used to be a
utility that you could run on a DOS peecee with the 1.2MB AT style
5-1/4" floppy drives that was reputed to read RX50 disks.  I never
tried it and we no longer have anything that can read that size floppy
(I packratted one but the boss pitched it when he found out...).
Check the DECUS software collection or possibly even an older VMS
freeware disk.  No idea what it was called.

If you can get the backup saveset, you should be able to transfer it
back to a VMS system for restoring.

Chris wrote:
> Do you happen to know anyone in the Long Island, New York area with a
> VAX system that can read RX50's?
> 
> If needed, I can supply an RX50 dual-diskette drive and/or an Rx33
> drive, as long as the system is capable of working with one or the
> other to read files that were originally written to RX50 via BACKUP.
> 

I happen to know a man who can read just about any media known and just 
about any format known.  His name is Chris Muller.  His company is 
"Muller Media Conversions"   He just happens to be located on Long 
Island!  Tell him Richard Gilbert sent you!

Contact Information:

info@mullermedia.com  for general information.

sales@mullermedia.com for a price quotation or to initiate dialogue 
concerning a new project.

support@mullermedia.com to ask about an existing project, or for 
software support.

Our phone number is 1-516-833-3067.  Note that you can also fax to the 
same number, since our computer PBX system can recognize incoming faxes 
and treat them properly. Therefore, we no longer have a separate number 
for faxes.
Mailing Address

     Muller Media Conversions
     21 Locust Street
     Manhasset, NY  11030

Rich Jordan wrote:

> On Dec 4, 11:10 am, Chris <archive.rai...@gmail.com> wrote:

>>Do you happen to know anyone in the Long Island, New York area with a
>>VAX system that can read RX50's?
(snip)

> Another possible option if you can find it.  There used to be a
> utility that you could run on a DOS peecee with the 1.2MB AT style
> 5-1/4" floppy drives that was reputed to read RX50 disks.  

Linux, or most unix systems, should be able to read the bits with
the appropriate drive.  Read the raw floppy device, usually with dd,
and write to a file which will be a byte image of the disk.

If there is a file system on it, you will then need to extract
the appropriate directory information.  If it is a single file
(backup saveset) you can probably do that without any directory
information.

-- glen

In article <B-SdnT5QFsAUsqXUnZ2dnUVZ_vadnZ2d@giganews.com>, "Richard B. Gilbert" <rgilbert88@comcast.net> writes:
>Chris wrote:
>> Do you happen to know anyone in the Long Island, New York area with a
>> VAX system that can read RX50's?
>> 
>> If needed, I can supply an RX50 dual-diskette drive and/or an Rx33
>> drive, as long as the system is capable of working with one or the
>> other to read files that were originally written to RX50 via BACKUP.
>> 
>
>I happen to know a man who can read just about any media known and just 
>about any format known.  His name is Chris Muller.  His company is 
>"Muller Media Conversions"   He just happens to be located on Long 
>Island!  Tell him Richard Gilbert sent you!

I know that character too.  However, it's going to cost you.

VAXman- @SendSpamHere.ORG wrote:
> In article <B-SdnT5QFsAUsqXUnZ2dnUVZ_vadnZ2d@giganews.com>, "Richard B. Gilbert" <rgilbert88@comcast.net> writes:
>> Chris wrote:
>>> Do you happen to know anyone in the Long Island, New York area with a
>>> VAX system that can read RX50's?
>>>
>>> If needed, I can supply an RX50 dual-diskette drive and/or an Rx33
>>> drive, as long as the system is capable of working with one or the
>>> other to read files that were originally written to RX50 via BACKUP.
>>>
>> I happen to know a man who can read just about any media known and just 
>> about any format known.  His name is Chris Muller.  His company is 
>> "Muller Media Conversions"   He just happens to be located on Long 
>> Island!  Tell him Richard Gilbert sent you!
> 
> I know that character too.  However, it's going to cost you.
> 

Yup!  It's how he makes his living.  It's not cheap to maintain that 
obsolete hardware.  It's not cheap to acquire and maintain documentation 
on all the weird formats that have been used to store data over the 
years.  There were encryption/decryption programs, 
compression/decompression programs, and Lord knows what else.  He has it 
and knows how to use it.

If you need to recover that data written in 1973, it IS going to cost you!!

What are YOU doing to ensure that your company's data can be recovered 
35 years from now if necessary?  It's likely that no one will ever need
that five or ten year old data again but you can't know that.

On 4 dec, 18:39, JF Mezei <jfmezei.spam...@vaxination.ca> wrote:
> Chris wrote:
> > Do you happen to know anyone in the Long Island, New York area with a
> > VAX system that can read RX50's?
>
> Are RX50s, normal 3.5inch diskettes ?
>
> I have a Vaxstation 3100 with a diskette drive that I could fire up. But
> am in Montreal so diskettes would have to be sent via mail/courier.

The RX50 is a 5.25" drive. They were used on the VAX 82x0/83x0 models
and on PDP-11's.

On 2008-12-05, H Vlems <hvlems@freenet.de> wrote:
> On 4 dec, 18:39, JF Mezei <jfmezei.spam...@vaxination.ca> wrote:
>> Are RX50s, normal 3.5inch diskettes ?
>
> The RX50 is a 5.25" drive. They were used on the VAX 82x0/83x0 models

The important thing is that they are low density, single sided, 80 track
diskettes with 10 512-byte sectors per track.

That combination is fairly unusual in the 5.25" world. Low-density
diskettes are typically 40 track double-sided diskettes with 9 sectors
per track. 
-- 
roger ivie
rivie@ridgenet.net

Roger Ivie wrote:
(snip, someone wrote

)
>>The RX50 is a 5.25" drive. They were used on the VAX 82x0/83x0 models

> The important thing is that they are low density, single sided, 80 track
> diskettes with 10 512-byte sectors per track.

> That combination is fairly unusual in the 5.25" world. Low-density
> diskettes are typically 40 track double-sided diskettes with 9 sectors
> per track. 

10 sectors means the gaps are smaller than the optimal size, but if
you keep the speed setting close I believe it is fine.

I still have two Teac FD55F, that is 80 cylinder double side low
density drives.  The more common Teac FD55GFV will read/write
low density with the appropriate signal on pin 2.  That one
normally runs at 360RPM so 300kb/s for low density, which is
commonly done by AT style controllers.  It might be that you can
get it down to 300RPM, though.

I believe most linux systems will be able to read them.
It looks like the /dev/fd0D800 device driver is for low density
10 sectors/track double side.  To get around that, you should read only
the sectors on side one using dd.

dd if=/dev/fd0D800 of=out count=10 bs=512
dd if=/dev/fd0D800 of=out count=10 bs=512 skip=20 seek=10
dd if=/dev/fd0D800 of=out count=10 bs=512 skip=40 seek=20
dd if=/dev/fd0D800 of=out count=10 bs=512 skip=60 seek=30
etc. (one dd for each track)

The driver is actually for a 3.5in drive, but it should
work just fine if you connect a 5.25in drive.  (You might
have to tell it in the BIOS that it is 3.5in.)

-- glen

In article <063e6764-b365-453b-af7d-bb21439ca04c@o2g2000yqd.googlegroups.com>, H Vlems <hvlems@freenet.de> writes:
>On 4 dec, 18:39, JF Mezei <jfmezei.spam...@vaxination.ca> wrote:
>> Chris wrote:
>> > Do you happen to know anyone in the Long Island, New York area with a
>> > VAX system that can read RX50's?
>>
>> Are RX50s, normal 3.5inch diskettes ?
>>
>> I have a Vaxstation 3100 with a diskette drive that I could fire up. But
>> am in Montreal so diskettes would have to be sent via mail/courier.
>
>The RX50 is a 5.25" drive. They were used on the VAX 82x0/83x0 models
>and on PDP-11's.

Wasn't it also the drive on the Pros?  I had a Pro-350, long since given
another home, that I believe has 2 RX50 drives.

On Dec 5, 6:53=A0am, VAXman-  @SendSpamHere.ORG wrote:
> In article <063e6764-b365-453b-af7d-bb21439ca...@o2g2000yqd.googlegroups.=
com>, H Vlems <hvl...@freenet.de> writes:
>
> >On 4 dec, 18:39, JF Mezei <jfmezei.spam...@vaxination.ca> wrote:
> >> Chris wrote:
> >> > Do you happen to know anyone in the Long Island, New York area with =
a
> >> > VAX system that can read RX50's?
>
> >> Are RX50s, normal 3.5inch diskettes ?
>
> >> I have a Vaxstation 3100 with a diskette drive that I could fire up. B=
ut
> >> am in Montreal so diskettes would have to be sent via mail/courier.
>
> >The RX50 is a 5.25" drive. They were used on the VAX 82x0/83x0 models
> >and on PDP-11's.
>
> Wasn't it also the drive on the Pros? =A0I had a Pro-350, long since give=
n
> another home, that I believe has 2 RX50 drives.

Brian,

Yes, Each Pro3x0 came with a dual (actually Siamese/cojoined might be
a better description) RX-50, two drives sharing critical components
mounted in a mirror-image fashion.

- Bob Gezelter, http://www.rlgsc.com (owner of several Professional
3x0 systems)

In article <3813f2b2-953b-40fa-96e8-76db4ab30c1e@j39g2000yqn.googlegroups.com>, Bob Gezelter <gezelter@rlgsc.com> writes:
>On Dec 5, 6:53=A0am, VAXman-  @SendSpamHere.ORG wrote:
>> In article <063e6764-b365-453b-af7d-bb21439ca...@o2g2000yqd.googlegroups.=
>com>, H Vlems <hvl...@freenet.de> writes:
>>
>> >On 4 dec, 18:39, JF Mezei <jfmezei.spam...@vaxination.ca> wrote:
>> >> Chris wrote:
>> >> > Do you happen to know anyone in the Long Island, New York area with =
>a
>> >> > VAX system that can read RX50's?
>>
>> >> Are RX50s, normal 3.5inch diskettes ?
>>
>> >> I have a Vaxstation 3100 with a diskette drive that I could fire up. B=
>ut
>> >> am in Montreal so diskettes would have to be sent via mail/courier.
>>
>> >The RX50 is a 5.25" drive. They were used on the VAX 82x0/83x0 models
>> >and on PDP-11's.
>>
>> Wasn't it also the drive on the Pros? =A0I had a Pro-350, long since give=
>n
>> another home, that I believe has 2 RX50 drives.
>
>Brian,
>
>Yes, Each Pro3x0 came with a dual (actually Siamese/cojoined might be
>a better description) RX-50, two drives sharing critical components
>mounted in a mirror-image fashion.

Thanks Bob... I thought so.  I have a RX50 transport here somewhere 
but I'd doubt I'd be able to hook it up to any of my current kit.


>- Bob Gezelter, http://www.rlgsc.com (owner of several Professional
>3x0 systems)

I would have kept my Pro350 and my MicroVAXen and sundry other bits 
of d|i|g|i|t|a|l antiquity and curio, but space for it was becoming
endangered by more and more kid crap.  I only wish that I would have
given away the kids and kept the nostaligia.
  

In article <3813f2b2-953b-40fa-96e8-76db4ab30c1e@j39g2000yqn.googlegroups.com>, Bob Gezelter <gezelter@rlgsc.com> writes:
> 
> Yes, Each Pro3x0 came with a dual (actually Siamese/cojoined might be
> a better description) RX-50, two drives sharing critical components
> mounted in a mirror-image fashion.
> 

   There's some software that will run on PCs that is supposed to write
   that format.  I used it to grab Pro software from Tim Shoppa's site
   after I picked up Brian's Pro and while I still had access to PCs
   with 5.25" drives.

   But it doesn't get the blocks used right, so I can run .EXE on the
   floppies because the task loader doesn't look at it, but I can't
   copy them because PIP does.  And I can't find the PIP command to
   set the blocks used value under Pro OS.

   Neither can I get my kid excited over playing Empire at frozen
   molasses speed.  But it would be have been fun to get DECnet up
   and running.

On Dec 4, 12:10=A0pm, Chris <archive.rai...@gmail.com> wrote:
> Do you happen to know anyone in the Long Island, New York area with a
> VAX system that can read RX50's?
>
> If needed, I can supply an RX50 dual-diskette drive and/or an Rx33
> drive, as long as the system is capable of working with one or the
> other to read files that were originally written to RX50 via BACKUP.

Chris,

What would be needed is to resurrect a system with the appropriate
controller. Reading the diskettes on another platform would not be
particularly productive as they would still have to be presented in a
form that BACKUP can use to extract the multi-volume saveset that
presumably is the subject of this query.

- Bob Gezelter, http://www.rlgsc.com

On Dec 5, 2:35=A0pm, Bob Gezelter <gezel...@rlgsc.com> wrote:
> On Dec 4, 12:10=A0pm, Chris <archive.rai...@gmail.com> wrote:
>
> > Do you happen to know anyone in the Long Island, New York area with a
> > VAX system that can read RX50's?
>
> > If needed, I can supply an RX50 dual-diskette drive and/or an Rx33
> > drive, as long as the system is capable of working with one or the
> > other to read files that were originally written to RX50 via BACKUP.
>
> Chris,
>
> What would be needed is to resurrect a system with the appropriate
> controller. Reading the diskettes on another platform would not be
> particularly productive as they would still have to be presented in a
> form that BACKUP can use to extract the multi-volume saveset that
> presumably is the subject of this query.
>
> - Bob Gezelter,http://www.rlgsc.com

If the diskette blocks can be read, as blocks in the same sense as VMS
understands them at low level, surely it doesn't hugely matter whether
it's VMS itself doing the reading? Doing it on VMS might be simpler,
especially in terms of checking whether the desired result has been
achieved, but if for whatever reason VMS isn't practical, an
acceptable alternative would surely be creating a known good block by
block image (eg with dd on a Linux box with a suitable floppy drive)
which can then be transferred to VMS for further processing ?

johnwallace4@yahoo.co.uk wrote:

> If the diskette blocks can be read, as blocks in the same sense as VMS
> understands them at low level, surely it doesn't hugely matter whether
> it's VMS itself doing the reading? 

Especially now that VMS has the freeware LDdriver, it is possible to do
a "ISO" image of media on another platform and bring the file over to
VMS and then use backup to read the save set.

On 2008-12-05, VAXman-  @SendSpamHere.ORG <VAXman-@SendSpamHere.ORG> wrote:
> Wasn't it also the drive on the Pros?  I had a Pro-350, long since given
> another home, that I believe has 2 RX50 drives.

Yes, it was used in the Pro as well as the Rainbow, DECmate II, the 
Micro PDP-11, and the MicroVAX II. I'm not sure about the MicroVAX I;
I've never seen one.
-- 
roger ivie
rivie@ridgenet.net

On 2008-12-05, JF Mezei <jfmezei.spamnot@vaxination.ca> wrote:
> Especially now that VMS has the freeware LDdriver, it is possible to do
> a "ISO" image of media on another platform and bring the file over to
> VMS and then use backup to read the save set.

Most RX50-based systems did a software interleave. The blocks were laid
out on the diskette in order (1 through 10; sector numbers start at
one), but the driver would mung the block number so that when the
machine asked for (say) block 2, it would actually read block 4. 
Taking a raw dump of a diskette and treating it as an ISO-like file
wouldn't deal with the software interleave.

Different RX50-based systems used different interleaves, so if you come
up with a scheme for (say) DECmate II diskettes, it won't work on Pro
diskettes.
-- 
roger ivie
rivie@ridgenet.net

Roger Ivie wrote:

> Most RX50-based systems did a software interleave. The blocks were laid
> out on the diskette in order (1 through 10; sector numbers start at
> one), but the driver would mung the block number so that when the
> machine asked for (say) block 2, it would actually read block 4. 

It is worse than that.   Even the tracks are not in order.   I wrote
a driver for a non-DEC floppy disk controller and had to deal with
it.   Here are my comments from the LBN to track/sector logic.
Perhaps they might help someone trying to decode an old floppy.

--------------------------------------------------------------
Track -- Convert a logical block number to a track/sector pair

The Track routine converts the requested Block Number (LBN) to
the correct track and sector number for an RX50.   DEC doesn't
have to do this in their DU: driver because the RQDXn controllers
do it for them.

The format of an RX50 is truly bizarre.   First of all, DEC starts
on the second track (#1), goes to the last track (#79), and then
jumps back to the first track (#0).

Instead of using sectors sequentially, every other one is used for
the first revolution, then the remaining sectors are used.   This
is referred to as 2:1 interleaving.

To further compound the confusion, the first sector for a track
is skewed two sectors from the previous track.

This controller numbers sectors in a manner that bears mentioning:
Each track has ten sectors of 512 bytes each.   Unlike tracks,
which are numbered from zero, sectors are numbered starting at one.

Thus, the first blocks of an RX50 will use the following tracks/sectors:

Blk:  0  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16 17 18 19 20 21

Trk:  1  1  1  1  1  1  1  1  1  1  2  2  2  2  2  2  2  2  2  2  3  3
Sect: 1  3  5  7  9  2  4  6  8 10  3  5  7  9  1  4  6  8 10  2  5  7

and the last blocks will use:

Blk: 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 ...
Trk:  79  79  79  79  79  79  79  79  79  79   0   0   0   0   0   0 ...
Sect:  6   8  10   2   4   7   9   1   3   5   8  10   2   4   6   9 ...
--------------------------------------------------------------

Alan Frisbie

On Fri, 5 Dec 2008 23:45:09 UTC, Alan Frisbie 
<Usenet02_Remove@Flying-Disk.com> wrote:

> It is worse than that.   Even the tracks are not in order.   I wrote
> a driver for a non-DEC floppy disk controller and had to deal with
> it.   Here are my comments from the LBN to track/sector logic.
> Perhaps they might help someone trying to decode an old floppy.
> 
> --------------------------------------------------------------
> Track -- Convert a logical block number to a track/sector pair
> 
> The Track routine converts the requested Block Number (LBN) to
> the correct track and sector number for an RX50.   DEC doesn't
> have to do this in their DU: driver because the RQDXn controllers
> do it for them.
> 
> The format of an RX50 is truly bizarre.   First of all, DEC starts
> on the second track (#1), goes to the last track (#79), and then
> jumps back to the first track (#0).

The sector numbering I can understand...it's not uncommon. But I'm 
baffled about using track 0 last...!
-- 
Bob Eager

Alan Frisbie wrote:
> Roger Ivie wrote:
> 
>> Most RX50-based systems did a software interleave. The blocks were laid
>> out on the diskette in order (1 through 10; sector numbers start at
>> one), but the driver would mung the block number so that when the
>> machine asked for (say) block 2, it would actually read block 4. 
> 
> It is worse than that.   Even the tracks are not in order.   I wrote
> a driver for a non-DEC floppy disk controller and had to deal with
> it.   Here are my comments from the LBN to track/sector logic.
> Perhaps they might help someone trying to decode an old floppy.
> 
> --------------------------------------------------------------
> Track -- Convert a logical block number to a track/sector pair
> 
> The Track routine converts the requested Block Number (LBN) to
> the correct track and sector number for an RX50.   DEC doesn't
> have to do this in their DU: driver because the RQDXn controllers
> do it for them.
> 
> The format of an RX50 is truly bizarre.   First of all, DEC starts
> on the second track (#1), goes to the last track (#79), and then
> jumps back to the first track (#0).
> 
> Instead of using sectors sequentially, every other one is used for
> the first revolution, then the remaining sectors are used.   This
> is referred to as 2:1 interleaving.
> 
> To further compound the confusion, the first sector for a track
> is skewed two sectors from the previous track.

I'd make a small bet that the sector skew resulted in bringing the first 
sector of the next track under the heads at about the time the heads had 
settled on the new track.

<snip>

VAXman- @SendSpamHere.ORG wrote:
> In article <063e6764-b365-453b-af7d-bb21439ca04c@o2g2000yqd.googlegroups.com>, H Vlems <hvlems@freenet.de> writes:
>> On 4 dec, 18:39, JF Mezei <jfmezei.spam...@vaxination.ca> wrote:
>>> Chris wrote:
>>>> Do you happen to know anyone in the Long Island, New York area with a
>>>> VAX system that can read RX50's?
>>> Are RX50s, normal 3.5inch diskettes ?
>>>
>>> I have a Vaxstation 3100 with a diskette drive that I could fire up. But
>>> am in Montreal so diskettes would have to be sent via mail/courier.
>> The RX50 is a 5.25" drive. They were used on the VAX 82x0/83x0 models
>> and on PDP-11's.
> 
> Wasn't it also the drive on the Pros?  I had a Pro-350, long since given
> another home, that I believe has 2 RX50 drives.
> 

And I seem to recall it debuted on the Rainbows and Pro-PDP series and 
later on the MVII (ba23/ba123 enclosures).  Great little drive at the 
time... (circa 1982/83 IIRC).

Michael Austin wrote:
> VAXman- @SendSpamHere.ORG wrote:
>> In article 
>> <063e6764-b365-453b-af7d-bb21439ca04c@o2g2000yqd.googlegroups.com>, H 
>> Vlems <hvlems@freenet.de> writes:
>>> On 4 dec, 18:39, JF Mezei <jfmezei.spam...@vaxination.ca> wrote:
>>>> Chris wrote:
>>>>> Do you happen to know anyone in the Long Island, New York area with a
>>>>> VAX system that can read RX50's?
>>>> Are RX50s, normal 3.5inch diskettes ?
>>>>
>>>> I have a Vaxstation 3100 with a diskette drive that I could fire up. 
>>>> But
>>>> am in Montreal so diskettes would have to be sent via mail/courier.
>>> The RX50 is a 5.25" drive. They were used on the VAX 82x0/83x0 models
>>> and on PDP-11's.
>>
>> Wasn't it also the drive on the Pros?  I had a Pro-350, long since given
>> another home, that I believe has 2 RX50 drives.
>>
> 
> And I seem to recall it debuted on the Rainbows and Pro-PDP series and 
> later on the MVII (ba23/ba123 enclosures).  Great little drive at the 
> time... (circa 1982/83 IIRC).

And also all of those DECmate I/II/III series (word processors)...

On 5 dec, 12:53, VAXman-  @SendSpamHere.ORG wrote:
> In article <063e6764-b365-453b-af7d-bb21439ca...@o2g2000yqd.googlegroups.=
com>, H Vlems <hvl...@freenet.de> writes:
>
> >On 4 dec, 18:39, JF Mezei <jfmezei.spam...@vaxination.ca> wrote:
> >> Chris wrote:
> >> > Do you happen to know anyone in the Long Island, New York area with =
a
> >> > VAX system that can read RX50's?
>
> >> Are RX50s, normal 3.5inch diskettes ?
>
> >> I have a Vaxstation 3100 with a diskette drive that I could fire up. B=
ut
> >> am in Montreal so diskettes would have to be sent via mail/courier.
>
> >The RX50 is a 5.25" drive. They were used on the VAX 82x0/83x0 models
> >and on PDP-11's.
>
> Wasn't it also the drive on the Pros? =A0I had a Pro-350, long since give=
n
> another home, that I believe has 2 RX50 drives.

I've only used Pro-350's as a console for a VAX 8550 and 8700. But we
used
an 8350 to copy files from an to the Pro-350 before we found an easier
way.
Hans

Alan Frisbie wrote:

> It is worse than that.   Even the tracks are not in order.   I wrote
> a driver for a non-DEC floppy disk controller and had to deal with
> it.   Here are my comments from the LBN to track/sector logic.
> Perhaps they might help someone trying to decode an old floppy.

So, if one were to make an "ISO" of the diskette on a different system,
the logic is known on how to reconstitute the data ?

aka: write a small program that would read the "ISO" in the dec
proprietary order and then rebuild a new ISO that was in block sequetial
number, at which point, you could mount it using the LD driver ?

Or is the block ordering done at such a low level that software wouldn't
be able to extract the blocks in the right order ?

Rich Jordan wrote:

> On Dec 4, 11:10�am, Chris <archive.rai...@gmail.com> wrote:
> > Do you happen to know anyone in the Long Island, New York area with
> > a VAX system that can read RX50's?
> > 
> > If needed, I can supply an RX50 dual-diskette drive and/or an Rx33
> > drive, as long as the system is capable of working with one or the
> > other to read files that were originally written to RX50 via BACKUP.
> 
> Another possible option if you can find it.  There used to be a
> utility that you could run on a DOS peecee with the 1.2MB AT style
> 5-1/4" floppy drives that was reputed to read RX50 disks.  I never
> tried it and we no longer have anything that can read that size floppy
> (I packratted one but the boss pitched it when he found out...).
> Check the DECUS software collection or possibly even an older VMS
> freeware disk.  No idea what it was called.
> 
> If you can get the backup saveset, you should be able to transfer it
> back to a VMS system for restoring.

I still have it, if you mean RX50DRVR. Source and all. It was able to
read RX50 DOS-floppies produced on a Rainbow. I never played with a VMS
one on it tho'. It would depend what the OP (Rich) wants to read. I'd
have to hook an old machine up to try.

Cheers - Dave.

-- 

On Dec 6, 3:19=A0pm, JF Mezei <jfmezei.spam...@vaxination.ca> wrote:
> Alan Frisbie wrote:
> > It is worse than that. =A0 Even the tracks are not in order. =A0 I wrot=
e
> > a driver for a non-DEC floppy disk controller and had to deal with
> > it. =A0 Here are my comments from the LBN to track/sector logic.
> > Perhaps they might help someone trying to decode an old floppy.
>
> So, if one were to make an "ISO" of the diskette on a different system,
> the logic is known on how to reconstitute the data ?
>
> aka: write a small program that would read the "ISO" in the dec
> proprietary order and then rebuild a new ISO that was in block sequetial
> number, at which point, you could mount it using the LD driver ?
>
> Or is the block ordering done at such a low level that software wouldn't
> be able to extract the blocks in the right order ?

That's what I was wondering. So long as you have read all the relevant
sectors (sectors are blocks, right?) and have them safely stored in
known places in some flavour of VMS file, a familiar development
environment such as VMS allows you to unskew and uninterleave at your
leisure?

I'm thinking (rightly or wrongly) that an RX50 is likely to be ODS1
rather than ODS2, which means decoding things could be relatively
simple even without LD.

On Dec 5, 6:45=A0pm, Alan Frisbie <Usenet02_Rem...@Flying-Disk.com>
wrote:
> Roger Ivie wrote:
> > Most RX50-based systems did a software interleave. The blocks were laid
> > out on the diskette in order (1 through 10; sector numbers start at
> > one), but the driver would mung the block number so that when the
> > machine asked for (say) block 2, it would actually read block 4.
>
> It is worse than that. =A0 Even the tracks are not in order. =A0 I wrote
> a driver for a non-DEC floppy disk controller and had to deal with
> it. =A0 Here are my comments from the LBN to track/sector logic.
> Perhaps they might help someone trying to decode an old floppy.
>
> --------------------------------------------------------------
> Track -- Convert a logical block number to a track/sector pair
>
> The Track routine converts the requested Block Number (LBN) to
> the correct track and sector number for an RX50. =A0 DEC doesn't
> have to do this in their DU: driver because the RQDXn controllers
> do it for them.
>
> The format of an RX50 is truly bizarre. =A0 First of all, DEC starts
> on the second track (#1), goes to the last track (#79), and then
> jumps back to the first track (#0).
>
> Instead of using sectors sequentially, every other one is used for
> the first revolution, then the remaining sectors are used. =A0 This
> is referred to as 2:1 interleaving.
>
> To further compound the confusion, the first sector for a track
> is skewed two sectors from the previous track.
>
> This controller numbers sectors in a manner that bears mentioning:
> Each track has ten sectors of 512 bytes each. =A0 Unlike tracks,
> which are numbered from zero, sectors are numbered starting at one.
>
> Thus, the first blocks of an RX50 will use the following tracks/sectors:
>
> Blk: =A00 =A01 =A02 =A03 =A04 =A05 =A06 =A07 =A08 =A09 10 11 12 13 14 15 =
16 17 18 19 20 21
>
> Trk: =A01 =A01 =A01 =A01 =A01 =A01 =A01 =A01 =A01 =A01 =A02 =A02 =A02 =A0=
2 =A02 =A02 =A02 =A02 =A02 =A02 =A03 =A03
> Sect: 1 =A03 =A05 =A07 =A09 =A02 =A04 =A06 =A08 10 =A03 =A05 =A07 =A09 =
=A01 =A04 =A06 =A08 10 =A02 =A05 =A07
>
> and the last blocks will use:
>
> Blk: 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 ...
> Trk: =A079 =A079 =A079 =A079 =A079 =A079 =A079 =A079 =A079 =A079 =A0 0 =
=A0 0 =A0 0 =A0 0 =A0 0 =A0 0 ...
> Sect: =A06 =A0 8 =A010 =A0 2 =A0 4 =A0 7 =A0 9 =A0 1 =A0 3 =A0 5 =A0 8 =
=A010 =A0 2 =A0 4 =A0 6 =A0 9 ...
> --------------------------------------------------------------
>
> Alan Frisbie

Hi Alan,

Thanks very much for the insights on the sector interleave. I have
managed to physically read the diskettes sequentially using a PC
floppy dump utility that I wrote decades ago.

I tried the old PUTR program on both the diskettes and on the disk-
images I had created. It didn't recognize the file system. This
confirms what Bob G. told me: that BACKUP modifies the diskette file
system--it no longer looks like true FILES-11.  If anybody out here
has any details on what those modifications are, maybe we can take
another step..

regards,  Chris

On Dec 7, 4:37=A0pm, Chris <archive.rai...@gmail.com> wrote:
> On Dec 5, 6:45=A0pm, Alan Frisbie <Usenet02_Rem...@Flying-Disk.com>
> wrote:
>
>
>
> > Roger Ivie wrote:
> > > Most RX50-based systems did a software interleave. The blocks were la=
id
> > > out on the diskette in order (1 through 10; sector numbers start at
> > > one), but the driver would mung the block number so that when the
> > > machine asked for (say) block 2, it would actually read block 4.
>
> > It is worse than that. =A0 Even the tracks are not in order. =A0 I wrot=
e
> > a driver for a non-DEC floppy disk controller and had to deal with
> > it. =A0 Here are my comments from the LBN to track/sector logic.
> > Perhaps they might help someone trying to decode an old floppy.
>
> > --------------------------------------------------------------
> > Track -- Convert a logical block number to a track/sector pair
>
> > The Track routine converts the requested Block Number (LBN) to
> > the correct track and sector number for an RX50. =A0 DEC doesn't
> > have to do this in their DU: driver because the RQDXn controllers
> > do it for them.
>
> > The format of an RX50 is truly bizarre. =A0 First of all, DEC starts
> > on the second track (#1), goes to the last track (#79), and then
> > jumps back to the first track (#0).
>
> > Instead of using sectors sequentially, every other one is used for
> > the first revolution, then the remaining sectors are used. =A0 This
> > is referred to as 2:1 interleaving.
>
> > To further compound the confusion, the first sector for a track
> > is skewed two sectors from the previous track.
>
> > This controller numbers sectors in a manner that bears mentioning:
> > Each track has ten sectors of 512 bytes each. =A0 Unlike tracks,
> > which are numbered from zero, sectors are numbered starting at one.
>
> > Thus, the first blocks of an RX50 will use the following tracks/sectors=
:
>
> > Blk: =A00 =A01 =A02 =A03 =A04 =A05 =A06 =A07 =A08 =A09 10 11 12 13 14 1=
5 16 17 18 19 20 21
>
> > Trk: =A01 =A01 =A01 =A01 =A01 =A01 =A01 =A01 =A01 =A01 =A02 =A02 =A02 =
=A02 =A02 =A02 =A02 =A02 =A02 =A02 =A03 =A03
> > Sect: 1 =A03 =A05 =A07 =A09 =A02 =A04 =A06 =A08 10 =A03 =A05 =A07 =A09 =
=A01 =A04 =A06 =A08 10 =A02 =A05 =A07
>
> > and the last blocks will use:
>
> > Blk: 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 ..=
..
> > Trk: =A079 =A079 =A079 =A079 =A079 =A079 =A079 =A079 =A079 =A079 =A0 0 =
=A0 0 =A0 0 =A0 0 =A0 0 =A0 0 ...
> > Sect: =A06 =A0 8 =A010 =A0 2 =A0 4 =A0 7 =A0 9 =A0 1 =A0 3 =A0 5 =A0 8 =
=A010 =A0 2 =A0 4 =A0 6 =A0 9 ...
> > --------------------------------------------------------------
>
> > Alan Frisbie
>
> Hi Alan,
>
> Thanks very much for the insights on the sector interleave. I have
> managed to physically read the diskettes sequentially using a PC
> floppy dump utility that I wrote decades ago.
>
> I tried the old PUTR program on both the diskettes and on the disk-
> images I had created. It didn't recognize the file system. This
> confirms what Bob G. told me: that BACKUP modifies the diskette file
> system--it no longer looks like true FILES-11. =A0If anybody out here
> has any details on what those modifications are, maybe we can take
> another step..
>
> regards, =A0Chris

My recollection is that BACKUP doesn't modify the filesystem as such,
it just does whatever you tell it to do. If the BACKUP output disk
(ette) was mounted Files11 when the backup was taken, then the saveset
should be readable as an ordinary file (or saveset, whatever), when
the disk is mounted files11. On the other hand, if the output disk was
mounted /FOREIGN, the same basic saveset contents are written, but not
as Files11 per se, just sequentially on the disk, starting at the
first appropriate block (0?1? some other small number?), and there is
thus no Files11 structure on the disk. This recollection comes from
years of taking backups to multiple RA60s so in principle things may
have changed, but then again when were RX50s in fashion ? Anyway,
correction/clarification most welcome.

Roger Ivie skrev:
> On 2008-12-05, VAXman-  @SendSpamHere.ORG <VAXman-@SendSpamHere.ORG> wrote:
>> Wasn't it also the drive on the Pros?  I had a Pro-350, long since given
>> another home, that I believe has 2 RX50 drives.
> 
> Yes, it was used in the Pro as well as the Rainbow, DECmate II, the 
> Micro PDP-11, and the MicroVAX II. I'm not sure about the MicroVAX I;
> I've never seen one.

Yeah, it was possible to have 'em on the uVAX I as well...
I've seen one, many many moons ago. Heck, it was even a VAXstation I. :-)

	Johnny

-- 
Johnny Billquist                  || "I'm on a bus
                                   ||  on a psychedelic trip
email: bqt@softjar.se             ||  Reading murder books
pdp is alive!                     ||  tryin' to stay hip" - B. Idol

On Dec 7, 4:01=A0am, "David Weatherall" <nos...@nowheren.no.how> wrote:
> Rich Jordan wrote:
> > On Dec 4, 11:10=A0am, Chris <archive.rai...@gmail.com> wrote:
> > > Do you happen to know anyone in the Long Island, New York area with
> > > a VAX system that can read RX50's?
>
> > > If needed, I can supply an RX50 dual-diskette drive and/or an Rx33
> > > drive, as long as the system is capable of working with one or the
> > > other to read files that were originally written to RX50 via BACKUP.
>
> > Another possible option if you can find it. =A0There used to be a
> > utility that you could run on a DOS peecee with the 1.2MB AT style
> > 5-1/4" floppy drives that was reputed to read RX50 disks.
>
> I still have it, if you mean RX50DRVR. Source and all. It was able to
> read RX50 DOS-floppies produced on a Rainbow. I never played with a VMS
> one on it tho'. It would depend what the OP (Rich) wants to read. I'd
> have to hook an old machine up to try.
>
> Cheers - Dave.
>
> --

Chris was the OP on this thread.