Compu-Pro Disk1 & Disk1A Controllers need Fixing/Testing - CP/M
This is a discussion on Compu-Pro Disk1 & Disk1A Controllers need Fixing/Testing - CP/M ; On Sun, 16 Mar 2008 00:46:29 -0800, glen herrmannsfeldt
wrote:
>Rolf Harrmann wrote:
>
>On Sat, 15 Mar 2008 11:24:39 -0500, "Robert J. Stevens" wrote:
>>Has anyone succeeded in using 5 1/4's in Place of 8" drives
>
>I have ...
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Re: Has anyone succeeded in using 5 1/4's in Place of 8" drives
On Sun, 16 Mar 2008 00:46:29 -0800, glen herrmannsfeldt
wrote:
>Rolf Harrmann wrote:
>
>On Sat, 15 Mar 2008 11:24:39 -0500, "Robert J. Stevens" wrote:
>>Has anyone succeeded in using 5 1/4's in Place of 8" drives
>
>I have an RT-11 system running on 5.25in Teac FD55GFR drives.
I presume hooked up to a RQDX3 which does support 5.25 but not 8"
and the 8" controller (RXV11 or RXV21) is not a disk contrller but an
interface to teh RX01/2 disk unit where the intelligence(?) lives.
>It helps to have a controller that can format them.
RQDXn controller can format 5.25 and if it's late firmware 3.5".
None of the DEC 8" controllers could format 8".
Allison
>
>-- glen
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Re: Has anyone succeeded in using 5 1/4's in Place of 8" drives
no.spam@no.uce.bellatlantic.net wrote:
(I wrote)
>>I have an RT-11 system running on 5.25in Teac FD55GFR drives.
> I presume hooked up to a RQDX3 which does support 5.25 but not 8"
> and the 8" controller (RXV11 or RXV21) is not a disk contrller but an
> interface to teh RX01/2 disk unit where the intelligence(?) lives.
No, it is on an MXV21. Much better than the DEC choices.
All on one board and it does know how to format. It expects
8 inch drives, so I have a cable specially wired for it.
-- glen
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Re: Has anyone succeeded in using 5 1/4's in Place of 8" drives
MikeS wrote:
(snip)
> I think you may have misunderstood (or I did). I think the OP wants to
> use 5 1/4HD (1.2Mb) drives (which, AFAIK, were not available in the
> Compupro days) to emulate an 8" drive; since the 5 1/4 drive (assuming
> it can be properly configured) looks exactly like an 8" drive to the
> hardware, no BIOS changes should be necessary (except, perhaps, for
> adding additional drive letters).
That is what I thought, too. The OP will have to say what
is really wanted.
-- glen
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Re: Has anyone succeeded in using 5 1/4's in Place of 8" drives
glen herrmannsfeldt wrote:
> MikeS wrote:
> (snip)
>
>> I think you may have misunderstood (or I did). I think the OP wants to
>> use 5 1/4HD (1.2Mb) drives (which, AFAIK, were not available in the
>> Compupro days) to emulate an 8" drive; since the 5 1/4 drive (assuming
>> it can be properly configured) looks exactly like an 8" drive to the
>> hardware, no BIOS changes should be necessary (except, perhaps, for
>> adding additional drive letters).
>
> That is what I thought, too. The OP will have to say what is really
> wanted.
I have an adapter that hooks 8" drives to a 5 1/5 cable on a PC and that
works.
Thanks to the WEB Page that Rolf Harrmann suggested I now have the
crossover linkup's.
Got to add some jumpers to the Adapter to get the 8" to see it
I have several Boot Floppies that will access A:, B:, C:, D: as 8"; So
that part is working
So with the Drives plugged as C: & D: just have to get the CompuPro to
see them
Thanks to all who responded.
Bob
http://home.iae.nl/users/pb0aia/cm/8-525.html
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Re: Has anyone succeeded in using 5 1/4's in Place of 8" drives
On Sun, 16 Mar 2008 15:52:15 -0800, glen herrmannsfeldt
wrote:
>no.spam@no.uce.bellatlantic.net wrote:
>
>(I wrote)
>>>I have an RT-11 system running on 5.25in Teac FD55GFR drives.
>
>> I presume hooked up to a RQDX3 which does support 5.25 but not 8"
>> and the 8" controller (RXV11 or RXV21) is not a disk contrller but an
>> interface to teh RX01/2 disk unit where the intelligence(?) lives.
>
>No, it is on an MXV21. Much better than the DEC choices.
>All on one board and it does know how to format. It expects
>8 inch drives, so I have a cable specially wired for it.
>-- glen
MXV21???? Is it DEC or not? The only MXV boards DEC did were
controllers or multifunction interface/memory boards none of wich have
FDC IO.
Wtih that said I have at least two of many other NON-DEC boards
that are far more functional than most of the DEC breed. One of the
better ones is the Andromeda Systems, Plessy and Charles River
Datasystems boards.
In any case it's not a 5.25 on a DEC designed 8" interface.
Allison
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Re: Has anyone succeeded in using 5 1/4's in Place of 8" drives
no.spam@no.uce.bellatlantic.net wrote:
(snip, I wrote)
>>No, it is on an MXV21. Much better than the DEC choices.
>>All on one board and it does know how to format. It expects
>>8 inch drives, so I have a cable specially wired for it.
> MXV21???? Is it DEC or not? The only MXV boards DEC did were
> controllers or multifunction interface/memory boards none of wich have
> FDC IO.
I believe it is MTI. It is register compatible with the DEC
two board system but fits on one.
> Wtih that said I have at least two of many other NON-DEC boards
> that are far more functional than most of the DEC breed. One of the
> better ones is the Andromeda Systems, Plessy and Charles River
> Datasystems boards.
> In any case it's not a 5.25 on a DEC designed 8" interface.
The interface was DEC designed, the implementation
was not. Then again, I don't know how much was borrowed.
It does use AMD2901 like you previously mentioned for DEC.
And, as I said, it can format disks, too!
-- glen
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Re: Has anyone succeeded in using 5 1/4's in Place of 8" drives
On Mon, 17 Mar 2008 16:04:34 -0800, glen herrmannsfeldt
wrote:
>no.spam@no.uce.bellatlantic.net wrote:
>(snip, I wrote)
>
>>>No, it is on an MXV21. Much better than the DEC choices.
>>>All on one board and it does know how to format. It expects
>>>8 inch drives, so I have a cable specially wired for it.
>
>> MXV21???? Is it DEC or not? The only MXV boards DEC did were
>> controllers or multifunction interface/memory boards none of wich have
>> FDC IO.
>
>I believe it is MTI. It is register compatible with the DEC
>two board system but fits on one.
>
>> Wtih that said I have at least two of many other NON-DEC boards
>> that are far more functional than most of the DEC breed. One of the
>> better ones is the Andromeda Systems, Plessy and Charles River
>> Datasystems boards.
>
>> In any case it's not a 5.25 on a DEC designed 8" interface.
>
>The interface was DEC designed, the implementation
>was not. Then again, I don't know how much was borrowed.
>It does use AMD2901 like you previously mentioned for DEC.
>
>And, as I said, it can format disks, too!
>
>-- glen
that was the one feature that all of the third party designers
added, formatting as DEC didn't. Many of them used the 2901
as it was the fastest thing available and fairly easy to use. The
real challange was geting it all on one board.
Allison
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Re: Has anyone succeeded in using 5 1/4's in Place of 8" drives
no.spam@no.uce.bellatlantic.net wrote:
(snip)
>
that was the one feature that all of the third party designers
> added, formatting as DEC didn't. Many of them used the 2901
> as it was the fastest thing available and fairly easy to use. The
> real challange was geting it all on one board.
http://www.bitsavers.org/pdf/microTe...floppyCtlr.pdf
There is a picture on page 45. There isn't much room left.
-- glen
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Re: Has anyone succeeded in using 5 1/4's in Place of 8" drives
Robert J. Stevens wrote:
> Has anyone succeeded in using 5 1/4's in Place of 8" drives
> I have a pair of FUJI Toshiba 5882M0K Black Face 1.2M 5 1/4 drives
> that I just put into a Housing.
> They worked as A: & B: on my PC Test Station. They format Floppies
> without errors
> Now I would like to hook them up to my CompuPro 816 with a Disk1A and
> make copies of some of my 8" floppies
> I post this way because my Newsgroup won't let me do a NEW Write
> USE
> trebor72SPAM@execpc.com -SPAM
I've got an Adapter that works for 5.25 to 8".
But I am not seeing Ready* on pin 34 of the 5.25 which is strapped to
Pin 22 of the 8".
What if I intercepted the Signal to the LED and inverted it and attached
to Pin 34 of the 5.25.
That would supply the Ready* low that the Disk1A FDC controller expects
The drives I have don't have any jumpers that affect PIN 34 as far as I
can tell
Any Thoughts Anyone
Bob
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Re: Has anyone succeeded in using 5 1/4's in Place of 8" drives
Hello Bob,
On Wed, 19 Mar 2008 13:33:26 -0500, "Robert J. Stevens" wrote:
>I've got an Adapter that works for 5.25 to 8".
>But I am not seeing Ready* on pin 34 of the 5.25 which is strapped to
>Pin 22 of the 8".
>What if I intercepted the Signal to the LED and inverted it and attached
>to Pin 34 of the 5.25.
>That would supply the Ready* low that the Disk1A FDC controller expects
>The drives I have don't have any jumpers that affect PIN 34 as far as I
>can tell
>Any Thoughts Anyone
Grnd. Sig. Sig. Name Sig Name Sig Grnd
33 34 **Ready ---------------<<------------ True Ready 8 7
33 34 **Disk Change ---------<<----------- Disk Change 12 11
33 34 **Ready ---------------<<----------------- Ready 22 21
Notes:
**- Most 5 1/4" disk drives do not provide a READY signal but send a
DISK CHANGE signal on line 34 of the interface. An 8" drive has
provisions for both signals. Likewise, most AT-style controllers
expect a DISK CHANGE signal on line 34, so lines 33 and 34 should
be connected to lines 11 and 12 of the 8" disk connector. Also,
some 8" drives provide a TRUE_READY signal which is more useful
than the standard READY
Rolf
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Re: Has anyone succeeded in using 5 1/4's in Place of 8" drives
Rolf Harrmann wrote:
(snip)
> **- Most 5 1/4" disk drives do not provide a READY signal but send a
> DISK CHANGE signal on line 34 of the interface. An 8" drive has
> provisions for both signals. Likewise, most AT-style controllers
> expect a DISK CHANGE signal on line 34, so lines 33 and 34 should
> be connected to lines 11 and 12 of the 8" disk connector. Also,
> some 8" drives provide a TRUE_READY signal which is more useful
> than the standard READY
The TEAC FD55GFR I previously mentioned has a jumper to select
between DISK CHANGE and READY. After not running the system for a
long time, I recently powered it up but with a different drive.
It took a few minutes to realize that with no ready the controller
would never read the disk. Otherwise, forcing ready probably
works.
I do remember the problem I had when I first ran this drive
on the 8" controller, connecting REDUCED WRITE CURRENT through.
For 8" drives it is supposed to be active for tracks greater
than 43. For 5.25in it is used to write non-HD disks in
HD drives. The first time I tried to format a disk
(RX02 formatted 5.25in disks are rare) it stopped on
track 43.
-- glen
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Re: Has anyone succeeded in using 5 1/4's in Place of 8" drives
Hello Glen,
On Wed, 19 Mar 2008 12:43:06 -0800, glen herrmannsfeldt wrote:
>The TEAC FD55GFR I previously mentioned has a jumper to select
>between DISK CHANGE and READY. After not running the system for a
>long time, I recently powered it up but with a different drive.
>It took a few minutes to realize that with no ready the controller
>would never read the disk. Otherwise, forcing ready probably
>works.
http://www.teac.com/DSPD/catalog.htm
FD55GFR-xxxx (5.25" 1.2MB Floppy Disk Drive)
Specifications and installation guide
http://www.teac.com/DSPD/pdf/5fd0050a.pdf
My Homepage with TEAC-Floppy Disk Drive.
http://www.hd64180-cpm.de/html/computer.html
Floppy Farbe schwarz von TEAC FD-55F für 5 1/4 Zoll Disketten
Floppy Farbe grau von TEAC FD-55GFR für 5 1/4 Zoll Disketten
FD55GFR-xxxx (5.25" 1.2MB Floppy Disk Drive)
Floppy Farbe grau von TEAC FD-505 für 5 1/4 und 3 1/2 Zoll Disketten
FD505-xxx (3.5" 1.44MB & 5.25" 1.2MB Combo Floppy Disk Drive)
I can boot CP/M 2.2 form TEAC FD-55GFR Floppy Disk 5 1/4 or
TEAC FD-505 Floppy Disk 3 1/2.
Rolf
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Re: Compu-Pro Disk1 & Disk1A Controllers need Fixing/Testing
Robert J. Stevens wrote:
Is there anyone out there that has used Shugart SA455's on the 5.25
connector of the Disk1A.
I have a pair that I would like to use with my Floppy only Machine.
I tried them but they almost work but not quite. Needs a Jumper Change???
I have a Pair of Mitsubishis connected to my Other system that has a
Q540 Hard drive and they work just fine.
Hate to have to keep swapping them back and forth
TIA
Bob in Wisconsin
USE this E-Mail Addy Minus "SPAM"
trebor72SPAM@execpc.com
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Re: Compu-Pro Disk1 & Disk1A Controllers need Fixing/Testing
On Thu, 20 Mar 2008 14:58:23 -0500, "Robert J. Stevens"
wrote:
>Robert J. Stevens wrote:
>Is there anyone out there that has used Shugart SA455's on the 5.25
>connector of the Disk1A.
>I have a pair that I would like to use with my Floppy only Machine.
>I tried them but they almost work but not quite. Needs a Jumper Change???
>I have a Pair of Mitsubishis connected to my Other system that has a
>Q540 Hard drive and they work just fine.
>Hate to have to keep swapping them back and forth
>TIA
>Bob in Wisconsin
>USE this E-Mail Addy Minus "SPAM"
>trebor72SPAM@execpc.com
The should work but likely you will have to select a slower step rate
as the old shugarts were very slow. Most of the half height or
Japanese drives (Teac, Mitsu, Toshiba, panasonic) all stepped at 3-6ms
but the shugart 4xx series were from 20-40ms step rates.
If the drive can't keep up it will fall out of step and when it goes
to read or write there will be errors from being on the wrong track.
Allison
-
Re: Compu-Pro Disk1 & Disk1A Controllers need Fixing/Testing
no.spam@no.uce.bellatlantic.net wrote:
> On Thu, 20 Mar 2008 14:58:23 -0500, "Robert J. Stevens"
> wrote:
>
>
>> Robert J. Stevens wrote:
>> Is there anyone out there that has used Shugart SA455's on the 5.25
>> connector of the Disk1A.
>> I have a pair that I would like to use with my Floppy only Machine.
>> I tried them but they almost work but not quite. Needs a Jumper Change???
>> I have a Pair of Mitsubishis connected to my Other system that has a
>> Q540 Hard drive and they work just fine.
>> Hate to have to keep swapping them back and forth
>> TIA
>> Bob in Wisconsin
>> USE this E-Mail Addy Minus "SPAM"
>> trebor72SPAM@execpc.com
>>
>
> The should work but likely you will have to select a slower step rate
> as the old shugarts were very slow. Most of the half height or
> Japanese drives (Teac, Mitsu, Toshiba, panasonic) all stepped at 3-6ms
> but the shugart 4xx series were from 20-40ms step rates.
> If the drive can't keep up it will fall out of step and when it goes
> to read or write there will be errors from being on the wrong track.
> Allison
>
What about the Possibility of Creating a BIOS that used High Density
Drives ie; 1.2M on the Disk1A 5.25 Connector.
With proper drive tables it ought to work if the Controller can support
them. That way it would give another way to Make Backups of 8" floppies
that would be accessible. I tried running a pair of 1.2's as C: & D: but
the adapter Settings/Jumpers interfere with the 8" Drives on A: B:.
Unless one could use two FDC's one for the Real 8"ers and one for the
5.25 1.2's. Perhaps a DISK1 and a Disk1A
Any Thoughts anyone
Bob
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Re: Compu-Pro Disk1 & Disk1A Controllers need Fixing/Testing
On Fri, 21 Mar 2008 06:46:34 -0500, "Robert J. Stevens"
wrote:
>no.spam@no.uce.bellatlantic.net wrote:
>> On Thu, 20 Mar 2008 14:58:23 -0500, "Robert J. Stevens"
>> wrote:
>>
>>
>>> Robert J. Stevens wrote:
>>> Is there anyone out there that has used Shugart SA455's on the 5.25
>>> connector of the Disk1A.
>>> I have a pair that I would like to use with my Floppy only Machine.
>>> I tried them but they almost work but not quite. Needs a Jumper Change???
>>> I have a Pair of Mitsubishis connected to my Other system that has a
>>> Q540 Hard drive and they work just fine.
>>> Hate to have to keep swapping them back and forth
>>> TIA
>>> Bob in Wisconsin
>>> USE this E-Mail Addy Minus "SPAM"
>>> trebor72SPAM@execpc.com
>>>
>>
>> The should work but likely you will have to select a slower step rate
>> as the old shugarts were very slow. Most of the half height or
>> Japanese drives (Teac, Mitsu, Toshiba, panasonic) all stepped at 3-6ms
>> but the shugart 4xx series were from 20-40ms step rates.
>> If the drive can't keep up it will fall out of step and when it goes
>> to read or write there will be errors from being on the wrong track.
>> Allison
>>
>What about the Possibility of Creating a BIOS that used High Density
>Drives ie; 1.2M on the Disk1A 5.25 Connector.
>With proper drive tables it ought to work if the Controller can support
>them. That way it would give another way to Make Backups of 8" floppies
>that would be accessible. I tried running a pair of 1.2's as C: & D: but
>the adapter Settings/Jumpers interfere with the 8" Drives on A: B:.
>Unless one could use two FDC's one for the Real 8"ers and one for the
>5.25 1.2's. Perhaps a DISK1 and a Disk1A
>Any Thoughts anyone
>Bob
Yes that is possible. Also the 3.5" 720k/1.44mb format is supportable
with that controller. Disk1A (also the plain1) use dma for transfer
so any format the 765 can do (all but the rare 2.88mb 3.5") is
possible meaning all PC formats and then some.
Personally I don't mess with the 1.2Mb format as I've had problems
with that media losing bits over time. If I need more than 800k from
a 5.25" floppy I go for 3.5" and 1.6mb (or formatted for PC as
1.44MB). The media is more available nad I had less trouble with
that.
Allison
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Re: Has anyone succeeded in using 5 1/4's in Place of 8" drives
On 3/17/08 9:41 AM, in article 13tst9r3ah0b879@corp.supernews.com, "Robert
J. Stevens" wrote:
> glen herrmannsfeldt wrote:
>> MikeS wrote:
>> (snip)
>>
I actually have found that the YE-380 drives from the PC-AT work pretty
well. I use them for 8" replacements on my CompuPro Disk 1 controller. They
have head load solenoids and can be jumpered to have the motor run all the
time just like 8" drives.
A minor modification to the PCB is required to put the *READY signal on pin
34, but otherwise they work like a charm.
Rich
http://www.altair32.com
http://www.classiccmp.org/cini
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Re: Compu-Pro Disk1 & Disk1A Controllers need Fixing/Testing
Robert J. Stevens wrote:
> no.spam@no.uce.bellatlantic.net wrote:
>> On Thu, 20 Mar 2008 14:58:23 -0500, "Robert J. Stevens"
>> wrote:
>>
>>
>>> Robert J. Stevens wrote:
>>> Is there anyone out there that has used Shugart SA455's on the 5.25
>>> connector of the Disk1A.
>>> I have a pair that I would like to use with my Floppy only Machine.
>>> I tried them but they almost work but not quite. Needs a Jumper
>>> Change???
>>> I have a Pair of Mitsubishis connected to my Other system that has a
>>> Q540 Hard drive and they work just fine.
>>> Hate to have to keep swapping them back and forth
>>> TIA
>>> Bob in Wisconsin
>>> USE this E-Mail Addy Minus "SPAM"
>>> trebor72SPAM@execpc.com
>>>
>>
>> The should work but likely you will have to select a slower step rate
>> as the old shugarts were very slow. Most of the half height or
>> Japanese drives (Teac, Mitsu, Toshiba, panasonic) all stepped at 3-6ms
>> but the shugart 4xx series were from 20-40ms step rates.
>> If the drive can't keep up it will fall out of step and when it goes
>> to read or write there will be errors from being on the wrong track.
>> Allison
>>
> What about the Possibility of Creating a BIOS that used High Density
> Drives ie; 1.2M on the Disk1A 5.25 Connector.
> With proper drive tables it ought to work if the Controller can support
> them. That way it would give another way to Make Backups of 8" floppies
> that would be accessible. I tried running a pair of 1.2's as C: & D: but
> the adapter Settings/Jumpers interfere with the 8" Drives on A: B:.
> Unless one could use two FDC's one for the Real 8"ers and one for the
> 5.25 1.2's. Perhaps a DISK1 and a Disk1A
> Any Thoughts anyone
> Bob
Can you jumper the 5.25" as A and B and the 8" drives as C and D, then boot from C or D?
I only ask because the H/Z-100 bios would allow this.
In fact, A & B are reserved for 5.25", and C & D for the 8".
Cables are 34-pin for the 5.25" and 50-pin for the 8".
Hard drive partitions start with E.
Jim
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Re: Compu-Pro Disk1 & Disk1A Controllers need Fixing/Testing
Robert J. Stevens wrote:
> no.spam@no.uce.bellatlantic.net wrote:
>> On Thu, 20 Mar 2008 14:58:23 -0500, "Robert J. Stevens"
>> wrote:
>>
>>
>>> Robert J. Stevens wrote:
>>> Is there anyone out there that has used Shugart SA455's on the 5.25
>>> connector of the Disk1A.
>>> I have a pair that I would like to use with my Floppy only Machine.
>>> I tried them but they almost work but not quite. Needs a Jumper
>>> Change???
>>> I have a Pair of Mitsubishis connected to my Other system that has a
>>> Q540 Hard drive and they work just fine.
>>> Hate to have to keep swapping them back and forth
>>> TIA
>>> Bob in Wisconsin
>>> USE this E-Mail Addy Minus "SPAM"
>>> trebor72SPAM@execpc.com
>>>
>>
>> The should work but likely you will have to select a slower step rate
>> as the old shugarts were very slow. Most of the half height or
>> Japanese drives (Teac, Mitsu, Toshiba, panasonic) all stepped at 3-6ms
>> but the shugart 4xx series were from 20-40ms step rates.
>> If the drive can't keep up it will fall out of step and when it goes
>> to read or write there will be errors from being on the wrong track.
>> Allison
>>
> What about the Possibility of Creating a BIOS that used High Density
> Drives ie; 1.2M on the Disk1A 5.25 Connector.
> With proper drive tables it ought to work if the Controller can support
> them. That way it would give another way to Make Backups of 8" floppies
> that would be accessible. I tried running a pair of 1.2's as C: & D: but
> the adapter Settings/Jumpers interfere with the 8" Drives on A: B:.
> Unless one could use two FDC's one for the Real 8"ers and one for the
> 5.25 1.2's. Perhaps a DISK1 and a Disk1A
> Any Thoughts anyone
> Bob
From
FLOPPY DRIVE DIRECTORY
THEREF(tm) Version 4.30 05/01/93
SIZE CAPACITY DISK XFER TIMING TRKs TOTALL. SECT POWERL. MTBF
MANUFACTURER MODEL NO. WDTH. HGT. UNFMT'D FORMT'D RPM RATE ACC. LATN. /IN. CYLs TRKs /TRK +12v +5v (HRS) WEIGHT ADDITIONAL COMMENTS
SHUGART SA400L 5.25 FULL 250KB 180KB 300
SHUGART SA455 5.25 HALF 500KB 360KB 300
SHUGART SA460 5.25 FULL 500KB 360KB 300
SHUGART SA800-1 8.00 FULL SINGLE SIDED
SHUGART SA800-2 8.00 FULL SINGLE SIDED
SHUGART SA860 8.00 HALF
SHUGART SA900-1 8.00 FULL SINGLE SIDED
MITSUBISHI MF353B,C 3.50 HALF 1.0MB 720KB 300 250Kb 94ms 100ms 135 80 160 9 0.1A 0.1A 10K 600g C=CMOS
MITSUBISHI MF355A,B,C 3.50 25.4 2.0MB 1.44MB 300 500Kb 94ms 100ms 135 80 160 18 0.3A 0.4A 10K 1500g C=CMOS
MITSUBISHI 4852 5.25 FULL 500KB 360KB 300
MITSUBISHI 4853 5.25 HALF 1.0MB 720KB
MITSUBISHI 4854 5.25 HALF 1.6MB 1.20MB
MITSUBISHI MF501A,B 5.25 HALF 500KB 360KB 300 250Kb 103ms 100ms 48 40 80 8 0.6A 0.4A 10K 1200g
MITSUBISHI MF504A,B 5.25 HALF 1.6MB 1.20MB DUAL 500Kb 94ms 83ms 96 80 160 15 0.6A 0.5A 10K 1200g DUAL SPEED
MITSUBISHI 2896-63 8.00 HALF
I recall the SA455 drive as a DSDD 5.25" replacement for the original IBMPC fdd, NOT DSHD as for the IMBPCAT.
I don't recall if it has FM capability, it should, depending on the controller.
I recall problems with the dual rpm, fixed data rate drives between the XT/AT's.
Note the Mitsubishi 4852 and MF501A,B are the only ones that match the characteristics of the Shugart SA455.
They are NOT 1.2M drives.
Jim