plausible disk upgrades, request for info

[Gil Kloepfer Jr.]

In article <5046 at thor.acc.stolaf.edu> mike at thor.acc.stolaf.edu (Mike Haertel) writes:
>I'm looking for information about disk drives that are known to work
>with the 3b1 (including those that would work only with a WD2010
>and/or the P5.1 modification).  I'm especially interested in disk
>Mike Haertel <mike at stolaf.edu>

This brings up some information that I've wanted to pass along to the
net for about a week now, and it seems an appropriate time to pass it
along...

When doing the second drive updates, it seems that Hitachi drives (in
particular, the 40MB ones) seem to have problems when used as the
second hard disk in a two-drive 3B1 system.  The system I was working
on ('Hi gern!') seemed to work fine when a 67MB Miniscribe was used
as the 2nd drive, and the Hitachi was the first drive.  When used
in the reverse configuration, the Hitachi would exhibit loads of disk
read errors.  This appears to be a timing problem, but I can't find
the trouble (cables too long?  chips adding too much delay?  some
other obscure problem?)  My assistant (hi Helen ;-) and I were up most
of the night trying different "cures" with no luck.  The only thing
not tried was the WD2010 (which I had sitting around, and now I could
kick myself for not trying THAT!).

If anyone else out there has peformed the 2nd disk upgrade and HAS been
able to fix this problem, please let me know!  Otherwise, this warning
is going out to the 3 dozen folks who may potientially do the hard disk
upgrade and have this problem.

Again, what baffles me is that it's ONLY Hitachi drives and some 20
meg drives (one person has reported to me) that exhibit this problem.
I've used a CDC Wren from a 3B2 (with >8 heads, BTW) and it worked
fantastic.

-------
| Gil Kloepfer, Jr.
| ICUS Software Systems/Bowne Management Systems (depending on where I am)
| ...icus!limbic!gil   or    gil at icus.islp.ny.us