5 Apr
2007
5 Apr
'07
4:46 p.m.
* info wrote:
________________________________
Does anyone know of a place to get a ST506 MFM drive? I have googled but
can't seem to located a new or pulled drive. I would one that is 40Meg
or larger. Thanks
Billy responds:
I see them all the time at the flea markets. And they show up on eBay and
Craig's list frequently. Wish I had known of your need. I gave one away
last weekend and put a couple more in the scrap barrel on Friday. I may
have a couple more at home but won't be going North for another 4 weeks.
Billy
5 Apr
5 Apr
7:02 p.m.
New subject: ST506 WTB:Micropolis 1325
Also looking for a Micropolis 1325 MFM Drive, 71/80MB , I've seen both the
ST506 and Mic. 1325 on eBay for like 600.00 which I think is crazy...
-JK
----- Original Message -----
From: "Billy Pettit" <Billy.Pettit at wdc.com>
To: <cctalk at classiccmp.org>
Sent: Thursday, April 05, 2007 8:46 PM
Subject: ST506
* info wrote:
________________________________
Does anyone know of a place to get a ST506 MFM drive? I have googled but
can't seem to located a new or pulled drive. I would one that is 40Meg
or larger. Thanks
Billy responds:
I see them all the time at the flea markets. And they show up on eBay and
Craig's list frequently. Wish I had known of your need. I gave one away
last weekend and put a couple more in the scrap barrel on Friday. I may
have a couple more at home but won't be going North for another 4 weeks.
Billy
--
No virus found in this incoming message.
Checked by AVG Free Edition.
Version: 7.5.446 / Virus Database: 268.18.26/746 - Release Date: 4/4/2007
1:09 PM
7 Apr
7 Apr
4:42 a.m.
New subject: ST506 WTB:Micropolis 1325
On Thu, 5 Apr 2007, Sridhar Ayengar wrote:
John Kourafas wrote:
I have an extensive collection of MFM/RLL drives and have _never_ run
across one with that interface in a 3.5" form-factor. Not sure that
anything of this sort existed. 5.25" 1/2-ht. was about as sophisticated
as they got.
The largest MFM drive ever made was _probably_ the Maxtor 2190 at 190MB
unformatted. ISTR that there was a logical limit to the number of
cylinders due to the control protocol (or perhaps limitations in the PC
BIOSes of the time) and physical limits to the number of sectors/cylinder
and the number of platters (the 2190 had 15 or 17?)
Steve
--
Also looking for a Micropolis 1325 MFM Drive,
71/80MB , I've seen both the
ST506 and Mic. 1325 on eBay for like 600.00 which I think is crazy...
What's the largest capacity 3.5" MFM HDD available? 
9:29 a.m.
New subject: ST506 WTB:Micropolis 1325
On 4/7/07, Steven N. Hirsch <shirsch at adelphia.net> wrote:
On Thu, 5 Apr 2007, Sridhar Ayengar wrote:
Tandon 262
Miniscribe 8425
The infamous Kalok Octagon KL-230
There were probabably a few others. I doubt there were any 3.5"
drives over 40 MB, though.
John Kourafas wrote:
I have an extensive collection of MFM/RLL drives and have _never_ run
across one with that interface in a 3.5" form-factor. Not sure that
anything of this sort existed. 5.25" 1/2-ht. was about as sophisticated
as they got. Also looking for a Micropolis 1325 MFM Drive,
71/80MB , I've seen both the
ST506 and Mic. 1325 on eBay for like 600.00 which I think is crazy...
What's the largest capacity 3.5" MFM HDD available? The largest MFM drive ever made was _probably_ the
Maxtor 2190 at 190MB
unformatted. ISTR that there was a logical limit to the number of
cylinders due to the control protocol (or perhaps limitations in the PC
BIOSes of the time) and physical limits to the number of sectors/cylinder
and the number of platters (the 2190 had 15 or 17?)
That's certainly close to the largest, if not the absolute largest.
DEC took the XT2190 and formatted it at 154MB as the RD54. I have a
few in MicroVAXen. Much more solid than the RD53 (Micropolis 1325),
and no jumper moving required (there's a single solderable jumper that
must be installed to turn a generic 1325 into an RD53 so that the
customer-runnable formatter recognizes it).
-ethan
8 Apr
8 Apr
2:03 a.m.
New subject: ST506 WTB:Micropolis 1325
On 07/04/2007 18:29, Ethan Dicks wrote:
On 4/7/07, Steven N. Hirsch <shirsch at
adelphia.net> wrote:
I've got a pair of 3.5" Rodime RO3065 drives which are 50MB MFM (ST412
interface, and not RLL).
I've got a few other ST412/MFM 3.5" drives:
NEC D3142 (42MB)
Western Digital WD384 (10MB)
Seagate ST125 (20MB)
Tandon TM362 (10MB)
and I used to have a Seagate 40MB and a Rodime 10MB, but both died.
--
Pete Peter Turnbull
Network Manager
University of York
On Thu, 5 Apr 2007, Sridhar Ayengar wrote:
I have an extensive collection of MFM/RLL drives and have _never_ run
across one with that interface in a 3.5" form-factor. Not sure that
anything of this sort existed. 5.25" 1/2-ht. was about as sophisticated
as they got.
Tandon 262
Miniscribe 8425
The infamous Kalok Octagon KL-230
There were probabably a few others. I doubt there were any 3.5"
drives over 40 MB, though. John Kourafas wrote:
> Also looking for a Micropolis 1325 MFM Drive, 71/80MB , I've seen
both
the
ST506 and
Mic. 1325 on eBay for like 600.00 which I think is crazy...
What's the largest capacity 3.5" MFM HDD available? 
6:45 p.m.
New subject: ST506 WTB:Micropolis 1325
Ethan Dicks wrote:
That's certainly close to the largest, if not the
absolute largest.
DEC took the XT2190 and formatted it at 154MB as the RD54. I have a
few in MicroVAXen. Much more solid than the RD53 (Micropolis 1325),
and no jumper moving required (there's a single solderable jumper that
must be installed to turn a generic 1325 into an RD53 so that the
customer-runnable formatter recognizes it).
Jerome Fine replies:
I always have a problem with DEC when I read about the
zero ohm resister that was actually used in place of
the jumper.
What was DEC's marketing policy? Add NOTHING!
What was DEC's hardware policy? Add NOTHING!
For marketing, DEC would buy a Micropolis 1325 for
about $ 500, add NOTHING (a zero to the price) and
re-sell as an RD53 for about $ 5000.
For hardware enhancements, DEC would buy a Micropolis 1325
and add NOTHING (a ZERO ohm resistor) and re-sell
as an RD53. DEC might have had Micropolis OEM the
drive even though the Micropolis name was still present.
Seagate used to do that with RZ type drives such as the
RZ28D-E which is just the ST32550N.
I seem to remember that DEC had a fix to slow the VAX 725
(at least one of the systems similar the the VAX 750).
Of course, Seagate did the same thing with their 20 MB
and 40 MB drives - removed a pin to prevent the arm
from accessing the other half of the drive (did not
install the pin actually with the 40 MB drives).
A hardware tech who serviced these drives told me how
they just removed the pin to double the capacity.
So DEC was certainly not unique. In point of fact,
I really miss the fantastic DEC Software. I wonder
what VMS would have been on an current Alpha?
PLEASE DO NOT REPLY!!!!!!!!!!!!!!!!!!
Sincerely yours,
Jerome Fine
--
If you attempted to send a reply and the original e-mail
address has been discontinued due a high volume of junk
e-mail, then the semi-permanent e-mail address can be
obtained by replacing the four characters preceding the
'at' with the four digits of the current year.
9 Apr
9 Apr
10:34 a.m.
New subject: ST506 WTB:Micropolis 1325
What was DEC's marketing policy? Add NOTHING!
What was DEC's hardware policy? Add NOTHING!
This reminds me of that comment 'We got nothing from the Arabs'. It's
true in the sense that what we got from them was the concept of zero --
'Nothing' -- and thus a positional number system notation. A major
advance IMHO.
-tony
7 Apr
7 Apr
10:49 a.m.
New subject: ST506 WTB:Micropolis 1325
Steven N. Hirsch wrote:
I have an extensive collection of MFM/RLL drives and
have _never_ run
across one with that interface in a 3.5" form-factor. Not sure that
anything of this sort existed. 5.25" 1/2-ht. was about as sophisticated
as they got.
I've got quite a few Rodime ones here - can't remember the model number
without going and digging them out, I'm afraid. I *think* they're 30MB.
They came amongst a pile of ex-Torch Computers stock, but I've never actually
*seen* one in a customer Torch system, so I'm not sure what (if any)
conclusion to draw from that.
The largest MFM drive ever made was _probably_ the
Maxtor 2190 at 190MB
unformatted. ISTR that there was a logical limit to the number of
cylinders due to the control protocol (or perhaps limitations in the PC
BIOSes of the time) and physical limits to the number of
sectors/cylinder and the number of platters (the 2190 had 15 or 17?)
Actually, I wondered this the other day; ESDI got a lot bigger (around 600MB I
think) but IIRC was pretty much the same interface. So quite what limited the
capacity of ST412 drives I'm not sure. I believe that cylinder seeking was
done by a sequence of single steps (rather than asking the drive: "seek to
this cylinder"), so there's probably an upper limit in the ST412 spec of how
fast step pulses can be sent (and beyond a certain size a drive will either
become slow as mole-asses, or some other timeout will come into play :-)
cheers
Jules
1:57 p.m.
New subject: ST506 WTB:Micropolis 1325
On 7 Apr 2007 at 13:49, Jules Richardson wrote:
Actually, I wondered this the other day; ESDI got a
lot bigger (around 600MB I
think) but IIRC was pretty much the same interface. So quite what limited the
capacity of ST412 drives I'm not sure. I believe that cylinder seeking was
done by a sequence of single steps (rather than asking the drive: "seek to
this cylinder"), so there's probably an upper limit in the ST412 spec of how
fast step pulses can be sent (and beyond a certain size a drive will either
become slow as mole-asses, or some other timeout will come into play :-)
ESDI uses a substantially different interface from ST412, even though
the cables may resemble each other. The interface itself was much
faster (15Mb/sec vs. 5Mb/sec) and IIRC, the data separator logic was
located on the drive. Up to 7 drives could be addressed by a
controller, though many PC controllers imposed a limitation of 2
drives (I suppose to be compatible with the WD1003-type interface).
Hard-sectoring was very common and the number of sectors per track
was rougly double that of ST412. I believe that the 670MB Miniscribe
that I have uses something like 54 sectors/track.
From a port interface perspective, a WD1007 (and
probably most other
PC ESDI controllers) appears to be a spitting image of an IDE
drive,
complete with support for the IDENTIFY command. As a matter of fact,
many OSes will mistakenly identify a WD1007+ESDI combination as an
IDE drive.
All in all, not a bad gizmo. etc. I think I've got WD and DTC
controllers for ESDI kicking around.
Cheers,
Chuck
6:06 p.m.
New subject: ST506 WTB:Micropolis 1325
Jules Richardson wrote:
I've owned a 40MB one for years. I would like to upgrade the machine.
It's a IBM PS/2 Model 50, and it's my favorite PC. Period.
Peace... Sridhar
I have an
extensive collection of MFM/RLL drives and have _never_ run
across one with that interface in a 3.5" form-factor. Not sure that
anything of this sort existed. 5.25" 1/2-ht. was about as
sophisticated as they got.
I've got quite a few Rodime ones here - can't remember the model number
without going and digging them out, I'm afraid. I *think* they're 30MB.
8 Apr
8 Apr
6:44 p.m.
New subject: ST506 WTB:Micropolis 1325
Jules Richardson wrote:
Actually, I wondered this the other day; ESDI got a
lot bigger (around
600MB I think) but IIRC was pretty much the same interface. So quite
what limited the capacity of ST412 drives I'm not sure. I believe that
cylinder seeking was done by a sequence of single steps (rather than
asking the drive: "seek to this cylinder"), so there's probably an
upper limit in the ST412 spec of how fast step pulses can be sent (and
beyond a certain size a drive will either become slow as mole-asses,
or some other timeout will come into play :-)
Jerome Fine replies:
I have a few 1.2 GB ESDI Hitachi drives which don't work
quite properly (they are slow on reading), but are very
nice for backups. I think that the sector size is a bit
small for what the Sigma RQD11-EC ESDI controller needs.
These are on my PDP-11/83. The smaller version Hitachi
ESDI drives of 600 MB were just great, as were XT8670E
drives from Maxtor. All of these drives are 5 1/4" FH.
I also used the 1.2 GB ESDI Hitachi drives on my PC under
W95 for a few years where the sector size did not seem to
be a problem on a Pentium 166 MHz system. I forget which
controller I used.
Sincerely yours,
Jerome Fine
--
If you attempted to send a reply and the original e-mail
address has been discontinued due a high volume of junk
e-mail, then the semi-permanent e-mail address can be
obtained by replacing the four characters preceding the
'at' with the four digits of the current year.
7 Apr
7 Apr
11:17 a.m.
New subject: ST506 WTB:Micropolis 1325
NEC made a ST-506 drive in 3.5 inch. There is a remote chance
I have one of these out in the garage...
----- Original Message -----
From: "Steven N. Hirsch" <shirsch at adelphia.net>
To: "General Discussion: On-Topic Posts Only" <cctech at classiccmp.org>
Sent: Saturday, April 07, 2007 8:42 AM
Subject: Re: ST506 WTB:Micropolis 1325
On Thu, 5 Apr 2007, Sridhar Ayengar wrote:
John Kourafas wrote:
I have an extensive collection of MFM/RLL drives and have _never_ run
across one with that interface in a 3.5" form-factor. Not sure that
anything of this sort existed. 5.25" 1/2-ht. was about as sophisticated
as they got.
The largest MFM drive ever made was _probably_ the Maxtor 2190 at 190MB
unformatted. ISTR that there was a logical limit to the number of
cylinders due to the control protocol (or perhaps limitations in the PC
BIOSes of the time) and physical limits to the number of sectors/cylinder
and the number of platters (the 2190 had 15 or 17?)
Steve
--
Also looking for a Micropolis 1325 MFM Drive,
71/80MB , I've seen both
the ST506 and Mic. 1325 on eBay for like 600.00 which I think is
crazy...
What's the largest capacity 3.5" MFM HDD available? 
11:49 p.m.
New subject: ST506 WTB:Micropolis 1325
On Apr 7, 2007, at 5:42 AM, Steven N. Hirsch wrote:
I don't know what to tell you. I had one in my first XT clone, ca.
1989. I just bought a few more because it was such a.. erm..
memorable drive. It was (is) a Miniscribe 3640. 40 MB, 3.5" HH, MFM,
slow, and loud as f*#&. Just off the top of my head, I also have a
Tandon TM262: 40 MB, 3.5" HH, MFM.
I think there were other Miniscribe drives up to 60 or 70 MB. TheRef
can verify, if it's possible even to still find a copy of it on the net.
3.5" MFM drives are not (were not) unusual, especially in the later
days before IDE started to take over the world.
Jeez, there are even a bunch listed in the Red Hill Guide.
http://redhill.net.au/d/d-a.html
ok
bear
What's the
largest capacity 3.5" MFM HDD available?
I have an extensive collection of MFM/RLL drives and have _never_
run across one with that interface in a 3.5" form-factor. Not sure
that anything of this sort existed. 5.25" 1/2-ht. was about as
sophisticated as they got.
8 Apr
8 Apr
2:35 a.m.
New subject: ST506 WTB:Micropolis 1325
On Apr 8, 2007, at 12:49 AM, r.stricklin wrote:
I don't know what to tell you. I had one in my
first XT clone, ca.
1989. I just bought a few more because it was such a.. erm..
memorable drive. It was (is) a Miniscribe 3640. 40 MB, 3.5" HH,
MFM, slow, and loud as f*#&. Just off the top of my head, I also
have a Tandon TM262: 40 MB, 3.5" HH, MFM.
DUH. Geez, I rag on people for doing this very thing. The 3640 is a
5.25" HH device. The drive I was speaking of is the Miniscribe 8450.
(I made this mistake almost constantly, as I was trying to find them
recently.)
ok
bear
8:21 a.m.
New subject: ST506 WTB:Micropolis 1325
On Apr 7, 2007, at 8:42 AM, Steven N. Hirsch wrote:
No, they definitely exist, I've installed a great many of them
into machines years ago. The company I worked for sold a lot of
PeeCees (my karma just hasn't been the same) and we used a HardCard
knock-off extensively; it was a 3.5" MFM drive bolted to a frame
attached to an MFM controller. I *think* the drive was made by
Miniscribe but I am not sure about that. It was a 20MB drive.
John Kourafas
wrote:
I have an extensive collection of MFM/RLL drives and have _never_
run across one with that interface in a 3.5" form-factor. Not sure
that anything of this sort existed. 5.25" 1/2-ht. was about as
sophisticated as they got. Also looking for a Micropolis 1325 MFM Drive,
71/80MB , I've seen
both the ST506 and Mic. 1325 on eBay for like 600.00 which I
think is crazy...
What's the largest capacity 3.5" MFM HDD available? The largest MFM drive ever made was _probably_ the
Maxtor 2190 at
190MB unformatted. ISTR that there was a logical limit to the
number of cylinders due to the control protocol (or perhaps
limitations in the PC BIOSes of the time) and physical limits to
the number of sectors/cylinder and the number of platters (the 2190
had 15 or 17?)
I believe this is correct.
-Dave
--
Dave McGuire
Port Charlotte, FL
2:56 p.m.
New subject: ST506 WTB:Micropolis 1325
On 8 Apr 2007 at 12:21, Dave McGuire wrote:
> > The largest MFM drive ever made was
_probably_ the Maxtor 2190
at
> 190MB unformatted. ISTR that there was a logical
limit to the
> number of cylinders due to the control protocol (or perhaps
> limitations in the PC BIOSes of the time) and physical limits to
> the number of sectors/cylinder and the number of platters (the 2190
> had 15 or 17?)
PC BIOSes generally supported only 1024 cylinders, but some BIOSes
extended the cylinder number by using a couple of high order bits in
the DH (head) register. So you could use your Maxtor XT2190 with
1224 cylinders if you knew how.
16 cylinders was the only hard controller limit; but even the XT2190
used only 15 heads (as did the Atasi/Priam 519). The controller
sector register is 8 bits wide, giving one a possiblity of 256
sectors per track and the cylinder was specified by a 16 bit register
pair, so the limit there would be 65536.
The issue that doomed MFM was the slow data transfer rate (5MHz).
The only reasonable way to put more sectors on a track (other than
using RLL) would have been to slow the spindle speed. MFM/ST412
just got too old.
Several ST412 interface drives had enough slop in the interface to
insert an extra 256 byte sector on cylinder 0 to record the drive
geometry. This was usually called sector 0, but any sector number
could have been used outside of the normal BIOS range.
Cheers,
Chuck
5 Apr
5 Apr
8:57 p.m.
New subject: ST506 WTB:Micropolis 1325
At 11:02 PM -0400 4/5/07, John Kourafas wrote:
Also looking for a Micropolis 1325 MFM Drive, 71/80MB ,
I've seen
both the ST506 and Mic. 1325 on eBay for like 600.00 which I think
is crazy...
A Micropolis 1325 MFM drive is a DEC RD53. The reason they go for so
much is because there are systems still in commercial use that need
these drives.
Zane
--
| Zane H. Healy | UNIX Systems Administrator |
| healyzh at aracnet.com (primary) | OpenVMS Enthusiast |
| MONK::HEALYZH (DECnet) | Classic Computer Collector |
+----------------------------------+----------------------------+
| Empire of the Petal Throne and Traveller Role Playing, |
| PDP-10 Emulation and Zane's Computer Museum. |
| http://www.aracnet.com/~healyzh/ |
6298
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6301
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17 comments
14 participants
participants (14)
-
ard＠p850ug1.demon.co.uk -
bear＠typewritten.org -
Billy.Pettit＠wdc.com -
bshannon＠tiac.net -
cclist＠sydex.com -
ethan.dicks＠gmail.com -
healyzh＠aracnet.com -
jhfinedp3k＠compsys.to -
john＠kourafas.com -
julesrichardsonuk＠yahoo.co.uk -
mcguire＠neurotica.com -
pete＠dunnington.plus.com -
ploopster＠gmail.com -
shirsch＠adelphia.net