'386 Unix Wars (ISC and >1024 cyls)

[Ed Hall]

In article <1663 at svin02.info.win.tue.nl> debra at info.win.tue.nl writes:
>In article <1991Jan4.025218.21453 at rand.org> edhall at rand.org writes:
>>This is false; ISC 2.0.1 supports disks with more than 1024 cylinders just
>>fine (I'm using all 1070 of mine, using a WD1006 controller).  The
>>partitioning program gives a bogus indication that there is a 1024
>>cylinder upper-bound, but if you ask it for more, it will give it to
>>you.
>
>So how did you do it? I told it to use up to cylinder 1223 (the last one
>on my disk) and ISC 2.0.1 complained and told me my system did not support
>more than 1024 cylinders and it changed the last cylinder back to 1023.

The problem is in their disk partitioning program, which not only prints
the bogus message saying you can't go above 1023, but also forces the
partition display to reduce the upper bound to 1023.  Just the same,
you get what you asked for.

This is as counter-intuitive as all hell--the only reason I even tried
it was that it was mentioned in a net posting a year or two back.  For
the average user who isn't going to be silly enough to ignore two warning
indications, 2.0.1 is as good as limited to 1024 cylinders.  The only
credit ISC gets from me on the matter is that they didn't manage to
break the rest of the system with regards to disks larger than 1024 cyls.

Be aware, however, that there are some disk controllers around that won't
go above cyl 1023.  Like I mentioned, the BIOS in my controller didn't
allow for it, although the controller itself did.

		-Ed Hall
		edhall at rand.org