21 Dec
2005
21 Dec
'05
6:49 p.m.
Oh my heavens, I don't think I am any sort of expert, but will try to help.
Do you have a document for the controller card? If not, I will try to find
my copy.
Yes, most RLL drives can be formatted to lower capacity and used on a MFM
controller, but some aren't reliable when used that way. I don't know which
are.
What happens when you start the formatter in debug? Does it attempt the
format and light up the drive or fail immediately?
Do you have any other old PC or XT machines you can try this in? 1701 is a
generic hard disk failure code, but it could imply that the bios is set
incorrectly and just doesn't recognize the drive. Shouldn't stop you from
formatting it, but then again, perhaps you don't need to, maybe you need to
fix something else that is wrong. A cabling issue perhaps.
The reason I ask about another PC is that I seem to recall the PS2 needing
a diskette to configure it, whereas an XT or clone wouldn't.
-T
At 01:45 PM 12/21/2005 +0100, you wrote:
Good morning Tom,
I've just read a topic on the cctalk mailing list in which you seem to be
en expert in old MFM/RLL disk drives.
I get many troubles in trying to place a WD disk controller with a
miniscribe 8438 disc. As many people do, I always get the famous 20 or
1701 errors whan trying to low level format with the debug command, under
MS dos (G=C800:5)
I think i've been trying all that could be possible : removing jumpers,
changing the WD driver card ... it never works. I've put another
combination of MFM disk drive plus WD controller, and I obtained good
results, so, it's not a problem with the computer, but certainly a problem
of disk and/or controller.
My controller is a WD1002A-WX1. I know it's for MFM disk, and I also know
that the 8438 disc is a RLL, but it's said that it can also be formatted
to 20Mbytes on a single WD MFM controller.
The machine is IBM PS2 model 30. The 8438 is used to replace the old
WDL-320 disk drive that doesn't work (it also sends the 1701 error code,
butI don't know how to low-level format it..
Many thanks if you can give me your help.
I apologize for disturbing you.
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Frederic BOSSU, F5INL
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Dorothy, The Wizard of Oz
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EN53wc
WAN/LAN/Telcom Analyst, Tech Writer, MCP, CCNA, Registered Linux User 385531
21 Dec
21 Dec
9:03 p.m.
At the expense of stating the obvious, have you eliminated the possibility
of the controller and its cables having a problem?
I do have the jumper settings for the controller if you need them.
Cheers,
Chuck
22 Dec
22 Dec
1:09 a.m.
Yes, most RLL drives can be formatted to lower
capacity and used on a MFM=20
controller, but some aren't reliable when used that way. I don't know which=
=20
are.
How can this be? With this sort of disk interface, the critical thing is
the timing between given edges (say rising edges) of the pulses on the
data line (the pulse width is not generally important). And I was under
the impressing that the set of times possible for the MFM interface was a
subset of the times for the RLL interface. And that a pulse stream from
the MFM interface was a possible pulse stream (albeit with a different
meaning) from the RLL interface too.
Sicne these ST506/ST412 drives are dumb devices (they don't try to
interpret the data pulses, they just record them and reproduce them), I
don't see how a drive can do RLL but not MFM.
-tony
2:07 a.m.
On 12/22/2005 at 1:09 AM ard at p850ug1.demon.co.uk wrote:
Sicne these ST506/ST412 drives are dumb devices (they
don't try to
interpret the data pulses, they just record them and reproduce them), I
don't see how a drive can do RLL but not MFM.
Just so--in my experience there were drives without sufficient headroom to
do MFM but not RLL, but not the reverse. And some drives could handle RLL
2,5 but not RLL 3,7. Some manufacturers designated certain drive models as
"RLL capable".
Cheers,
Chuck
3:16 a.m.
Interesting, My CSC Hard Drive Bible VIII indicates there are 3
different 8438 drives.
My book says
8438/8438F, 32 Megs formatted, 4 heads, 615 Cyl, 26 sectors,
68/40 MSecond timing RLL
Then there is a third
8438XT, 31 Megs formatted, 4 heads, 615 Cyl, 26 sectors, 68
MSecond timing XT-IDE
As to the Western digital 1002A-WX1, it is an 8 bit MFM controller
for two hard drives only. The default jumpers are W3, W4-2 & 3, W6-2 7
3,W8-2 & 3, S1-8 (AT mode) To format use G=C800:5 as you already know.
Hope this helps.
Doesn't the Model 30 have a built in disk controller that you have to
disable is use an ISA disk controller? I think there is IDE on the
motherboard. You might need the actual PS2 setup disks for the model
30. Is yours a 8086 or 80286 model 30? Most of the PS2 line had their
own set up floppy disk.
Paxton
--
Paxton Hoag
Astoria, OR
USA
3:37 a.m.
Interesting, My CSC Hard Drive Bible VIII indicates
there are 3
different 8438 drives.
My book says
8438/8438F, 32 Megs formatted, 4 heads, 615 Cyl, 26 sectors,
68/40 MSecond timing RLL
If he has one of these, then ok.
Then there is a third
8438XT, 31 Megs formatted, 4 heads, 615 Cyl, 26 sectors, 68
MSecond timing XT-IDE
XT-IDE? What's that? I didn't know that there was
an XT compatible IDE
controller, except a few rare and expensive ones.
Doesn't the Model 30 have a built in disk
controller that you have to
disable is use an ISA disk controller? I think there is IDE on the
motherboard. You might need the actual PS2 setup disks for the model
30. Is yours a 8086 or 80286 model 30? Most of the PS2 line had their
own set up floppy disk.
Good questions all. I don't see how he can proceed if
he hasn't got the
setup disk and figured out for sure if there's a controller on board and
that he's disabled it.
Paxton
3:43 a.m.
On Wed, 21 Dec 2005, Tom Peters wrote:
It's 8 bit IDE.
At the time, they were neither rare, nor very expensive.
If you waited until now to buy one, then you may be outa luck.
8438XT, 31
Megs formatted, 4 heads, 615 Cyl, 26 sectors, 68
MSecond timing XT-IDE
XT-IDE? What's that? I didn't know that there was
an XT compatible IDE
controller, except a few rare and expensive ones.
4:03 a.m.
On 12/21/2005 at 7:43 PM Fred Cisin wrote:
On Wed, 21 Dec 2005, Tom Peters wrote:
It's 8 bit IDE.
At the time, they were neither rare, nor very expensive.
If you waited until now to buy one, then you may be outa luck.
Sometimes called XTA; these drives could do 8 bit data transfers--i.e.,
they actually paid attention to IOCS16\.
Cheers,
Chuck
8438XT,
31 Megs formatted, 4 heads, 615 Cyl, 26 sectors, 68
MSecond timing XT-IDE
XT-IDE? What's that? I didn't know that there was
an XT compatible IDE
controller, except a few rare and expensive ones.
6953
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