19 Jun
2009
19 Jun
'09
10:40 p.m.
Anyone remember the difference between the various Western Digital MFM disk controllers?
I've got a few in front of me right now, and I'm trying to figure out which would
be the best for this Compaq Portable 286.
I've got the good ol' WD1002A-WX1, and what looks to be the bigger verison, the
WD1002S-WX2, then another, even longer card, the one that came stock with the Compaq, the
WD1015-PL03.
Now, here's the dilemma. The stock card won't respond to the usual debug commands
- they just freeze the computer. The original 20mb 3 1/2" Miniscribe hard drive is
dead (won't even spin). I am going to replace it with a similar 3 1/2" form
factor drive - the NEC D3142. (43mb! Woo!) I already got the drive formatted and working
on the small WD1002A-WX1 card, but it's been a while since I worked with MFM
controllers - and I seem to remember the WD1002S-WX2 being faster or something.
Also, I don't remember the calculations for optimum interleave, I used 3, since that
was the default....
Pointers?
-Ian
20 Jun
20 Jun
3:06 a.m.
On Jun 19, 2009, at 10:40 PM, Mr Ian Primus wrote:
Anyone remember the difference between the various
Western Digital
MFM disk controllers? I've got a few in front of me right now, and
I'm trying to figure out which would be the best for this Compaq
Portable 286.
I've got the good ol' WD1002A-WX1, and what looks to be the bigger
verison, the WD1002S-WX2, then another, even longer card, the one
that came stock with the Compaq, the WD1015-PL03.
Now, here's the dilemma. The stock card won't respond to the usual
debug commands - they just freeze the computer. The original 20mb 3
1/2" Miniscribe hard drive is dead (won't even spin). I am going to
replace it with a similar 3 1/2" form factor drive - the NEC D3142.
(43mb! Woo!) I already got the drive formatted and working on the
small WD1002A-WX1 card, but it's been a while since I worked with
MFM controllers - and I seem to remember the WD1002S-WX2 being
faster or something.
Wow. I used to know *all* of those part numbers, have been
shaking my head trying to jog my memory for the past few minutes, but
it seems that info is just gone. :-(
Also, I don't remember the calculations for
optimum interleave, I
used 3, since that was the default....
You can use something like Spinrite to discover the proper
interleave for a disk subsystem, and it will even format in-place
(track at a time) and preserve data. I used it all the time, it was
quite good.
-Dave
--
Dave McGuire
Port Charlotte, FL
8:26 a.m.
Christian Corti wrote:
On Fri, 19 Jun 2009, Mr Ian Primus wrote:
Um that depends, the models the OP was discussing IIRC are XT controlers
which *DO* for the most part come with their own BIOS, as the XT roms
know nothing about hard disks of any sort.
However for 16 bit AT type controllers you are mostly correct, that they
don't need a BIOS since the AT rom does know about hard disks.
There where exceptions however I have (or used to anyways) in my box of
old cards a Seagate (I think) RLL controler that did have onboard bios,
I believe for very old AT type boards that didn't have CMOS settable
drive parameters.
Cheers,
Phill.
--
Phill Harvey-Smith, Programmer, Hardware hacker, and general eccentric !
"You can twist perceptions, but reality won't budge" -- Rush.
Now, here's the dilemma. The stock card
won't respond to the usual
debug commands - they just freeze the computer. The original 20mb 3 1/2"
Normal MFM controllers never come with an own BIOS, so there's nothing
to jump to. 
5:06 p.m.
The stock card requires a setup utility.
-----Original Message-----
From: cctalk-bounces at classiccmp.org [mailto:cctalk-bounces at classiccmp.org]
On Behalf Of Mr Ian Primus
Sent: Friday, June 19, 2009 7:40 PM
To: cctalk at classiccmp.org
Subject: ISA MFM disk controllers
Anyone remember the difference between the various Western Digital MFM disk
controllers? I've got a few in front of me right now, and I'm trying to
figure out which would be the best for this Compaq Portable 286.
I've got the good ol' WD1002A-WX1, and what looks to be the bigger verison,
the WD1002S-WX2, then another, even longer card, the one that came stock
with the Compaq, the WD1015-PL03.
Now, here's the dilemma. The stock card won't respond to the usual debug
commands - they just freeze the computer. The original 20mb 3 1/2"
Miniscribe hard drive is dead (won't even spin). I am going to replace it
with a similar 3 1/2" form factor drive - the NEC D3142. (43mb! Woo!) I
already got the drive formatted and working on the small WD1002A-WX1 card,
but it's been a while since I worked with MFM controllers - and I seem to
remember the WD1002S-WX2 being faster or something.
Also, I don't remember the calculations for optimum interleave, I used 3,
since that was the default....
Pointers?
-Ian
23 Jun
23 Jun
7:23 p.m.
Anyone remember the difference between the various
Western Digital MFM disk controllers? I've got a few in front of me right now, and
I'm trying to figure out which would be the best for this Compaq Portable 286.
I've got the good ol' WD1002A-WX1, and what looks to be the bigger verison, the
WD1002S-WX2,
WX-1 is 2 MFM hard drives only, WX-2 is hard drives plus two floppys.
My CSC Hard Drive manual says it is an 8 bit contoller for two hard
drives. To format use G=C800:5 (Why is that so familiar!!!)
From the book the default jumpers on the WD 1002A-WX1
are
W3,W4-2 & 3, W6-2 & 3, W8-2 & 3, S1-8 (AT Mode)
then another, even longer card, the one that came stock
with the Compaq, the WD1015-PL03.
That doesn't show up in the book, but it was probably made for compaq.
The first card (WD1002A-WX1) should work. However the setup programs
were custom for Compaq. I don't think you can just use debug unless
you know Compaq codes.
Now, here's the dilemma. The stock card won't
respond to the usual debug commands - they just freeze the computer. The original 20mb 3
1/2" Miniscribe hard drive is dead (won't even spin). I am going to replace it
with a similar 3 1/2" form factor drive - the NEC D3142. (43mb! Woo!) I already got
the drive formatted and working on the small WD1002A-WX1 card, but it's been a while
since I worked with MFM controllers - and I seem to remember the WD1002S-WX2 being faster
or something.
I think you will need the compaq set up disks. I still have a set but
not sure where they are. I might be able to locate them if you need me
to.
Also, I don't remember the calculations for
optimum interleave, I used 3, since that was the default....
I think an interleave of 3 would be OK as it is an XT class
controller. But, as mentioned, Spinrite can optimize it for you. The
nec drive is an AT class drive at 28 ms. It should work fine.
Pointers?
-Ian
--
Paxton Hoag
Astoria, OR
USA
24 Jun
24 Jun
10:42 a.m.
On Jun 23, 2009, at 7:23 PM, Paxton Hoag wrote:
--
Dave McGuire
Port Charlotte, FL
I think an interleave of 3 would be OK as it is an XT
class
controller. But, as mentioned, Spinrite can optimize it for you. The
nec drive is an AT class drive at 28 ms. It should work fine.
I hope you're not suggesting that the average access time has
something to do with interleave restrictions, because it doesn't.
-Dave
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