From: jliukkon@klaava.Helsinki.FI (Juha-Matti Liukkonen)
Newsgroups: comp.sys.ibm.pc.hardware
Subject: UPDATE: IDE-disk trash (w/Stacker)
Date: 14 Sep 92 22:20:52 GMT
Organization: University of Helsinki

Hello there again.

I posted about my hard drive malfunctions a couple of days ago, and this
is an update of the situation. I have now obviously been able to fix the
problem.

First, a short version of the setup & the problem:

A 100% self-made computer, consisting of
- 386SX-25, 32 Kb CPU cache, AMI BIOS 12/20/90
  o most important BIOS options: CPU cache off/on/post-write,
  o Bus speed ATCLK/6 (= 8 1/3 MHz, std) or ATCLK/4 (= 12.5 MHz)
- no-name multi-I/O + IDE + floppy controller card (LPT1, COM1, COM2)
- Trident 8900C 3.01 1 Mb VGA board
- SoundBlaster 1.5 (IRQ 5)
- A modem card (COM 4, IRQ 3)
- Conner CP3044 IDE hard disk, 25 ms, 42 Mb
- DOS 5.00, QEMM 6.00/UMB_DRVR 5.22, Stacker 2.0, 4DOS 4.01, Windows
  3.1, PC-CACHE 7.1/NCACHE 6.00/SMARTDRV 4.0

After I had tested another floppy drive on my machine, I installed a new
hard drive cable to replace the old one (it's connectors were pried from
another cable and connected to this one using a chair). Then I put the
machine back together - just to get a dozen erratic error messages from
all the different pieces of my boot-up software (stacker.com checksum
error, 4DOS page table missing, ...). And when the thing finally booted
up, I had zillions of loose sectors all around my Stacked disk.

Well, first I put the old HD cable back of course. But the problems
persist! OK, I reseat the I/O-card and the connectors. No use... Still
completely erratic behaviour at boot-up.

I run SCHECK, and find 50% of my files truncated to 4096 bytes. OK, I
reformat the drive using a clean DOS floppy, repartition it to one
chunk, and run Norton Calibrate's Rigorous pattern testing on it - at
the higher bus speed the drive hadn't been able to handle before.

Now I have a 18.83 ms drive working relatively OK. However, Windows
reports "error reading from drive C", and I fathom this is because of
the 50% higher bus speed. I re-calibrate the disk with the standard bus
speed, re-install everything, and find that the original problems
remain.

At this point I reformatted the disk, and installed everything with all
imaginable different cache/memory manager/all I could think of settings
(and repeated this about five times) only to find that the erratic error
messages keep reappearing.

*****

That was the situation then, here's what I did:

I dismantled the computer, every card and connector. I checked all the
boards for burned components, possible short circuits etc etc, and found
nothing. Then I put it all back together piece by piece. With just the
motherboard, I/O-IDE card, and Video card, I booted for the first time.

Now I get a message "CMOS & XCMOS values invalid". And I had _not_ reset
these! Alright, I set the values to be what they are supposed to be, and
voila: everything runs OK.

Now format from a clean DOS disk, stack the disk, and restore my
backups. Everything works fine, even Windows. I install the SoundBlaster
- everything still OK. Install the modem - still OK. I'm very happy!

The problem seemed to be either a) in the CMOS values, or b) a faulty
connection _somewhere_ in the computer. And as the I/O card was the only
one I removed while I swapped the cable, I had of course tried to reseat
that, and even on different slots, but to no avail. So it seems that the
CMOS values are to blame, even though they appeared to be all right.
This raises a question for the wise to answer: can the CMOS and XCMOS
values be garbled so, that the settings _appear_ to be OK when one looks
at the setup screens?

*****

P.S. I've had just one problem after that, and it should actually be
discussed in comp.os.ms-windows: I set the Windows permanent swap file
to the unstacked portion of the drive, but set the temp variable to
point to the stacked drive. Now it was obviously this that caused
Windows to complain about "error reading drive C" sometimes with QEMM,
and constantly with UMB_DRVR while 32-bit disk access was on. When I
removed the 32-bit DA, everything's been working OK.

*****

Thanks for having been bearing with me! I do hope this quite
inconvenient experience will be of use to someone someday.

-- 
               Juha Liukkonen, aka jliukkon@cc.helsinki.fi
       University of Helsinki, Dept. of Paranormal Investigations
           "Trust me, I know what I'm doing." - Sledge Hammer
Newsgroups: comp.sys.ibm.pc.hardware