What is the "Two-Drive Bug"?

[Randy Jarrett WA4MEI]

In article <162 at aquinas.UUCP> sean at aquinas.UUCP (Sean McCollister) writes:
>
>	Would someone please mail me a description of the so-called "two-
>hard-drive bug" I've seen mentioned here in the past?  I never paid atten-
>tion before, since I didn't have two hard disks.  Now that I DO have two
>drives, and a migraine headache to go along with them, I'd like to hear
>from those of you who have struggled to make a dual-disk configuration work
>with Microport (System V/AT 2.3.0, with and without Merge 286).
>
>	In a nutshell, my problem is that the first drive (whatever the
>brand or model, I've tried several) literally seems to disintegrate over
>a period of several weeks.  Bad tracks seem to materialize out of thin
>air.  When I run fdisk to scan for bad tracks, it never picks up anything
>but those listed on the error-map shipped with the disk.  Since I installed
>the second disk, I have replaced the first drive 5 times, and the controller
>and cables twice.  Through all this, the second disk has worked flawlessly.
>BOTH drives work flawlessly if I remove UNIX (tm of AT&T) and format them
>with DOS.  None of this happens when only one drive is present.
>

I have been having the same problems as you have but on the
oposite drives. My drive 0 ( CDC Wren ) has not had any problems
since day one but when I added the second drive (first one
was a Micropolis 1304 ) I had the bad sectors start popping up
constantly. I figured that maybe the drive was starting to wear
out so I swapped it with another CDC Wren (85Mb) so that I had
two identical drives. I keep getting the problems with the second
drive so I did a backup and swapped the drives.  The problem stayed
on the second drive.

I have since taken off the second CDC and have a Seagate 4096 on there
now.  All the drives have been given an extensive going over with
Novells Compsurf program several times looking for any problem sectors
without any luck.  I have run the drives on a Xenix system and they
did not have problem one.  I then installed Xenix on my system and ran
all kind of tests for about a week and not a problem one out of the 
drives.

As it is now I have to run fsck everyday and usually two or three
times to get everything straightened up.  Occasionally I have to 
just dump the drive and re-install it (mkfs).  

I have tried the Microport bbs and not found any replacement drivers
there for the 286 version only the 386.  I have found passing comments
on the system about the problem but no solutions.  I have sent several
pieces of email to both Sully and Plocher and have not received any
replys.

As it stands now I am hoping that when the ver 2.4 release comes out
that the problems will be corrected ( and maybe a better asy driver).


-- 
Randy Jarrett  WA4MEI 
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