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From: cm@jet.uucp (colin manning)
Newsgroups: comp.unix.sysv386
Subject: ISC 2.2.1 + Fujitsu 1.2Gb drive + AHA 1740 EISA SCSI
Message-ID: <1991Apr30.120043.25022@jet.uucp>
Date: 30 Apr 91 12:00:43 GMT
Organization: Joint European Torus
Lines: 44

I've just got a Intel 403e (33Mhz 486) with 16Mb RAM, 1740 EISA SCSI
and a Fujitsu 1.2Gb SCSI drive (model 2266sa I believe).

Q1:
Machine seems to work fine, but for the following *very* serious problem.

If I do something that is very disk intensive, I can get the SCSI 
bus/drive/controller hung, and all I can do is reboot. The disk access
light stays on permanently (suggesting system is midway through a
SCSI command ?), and the all Unix activity ceases. The kernel does
not appear to have crashed, since it will still echo keyboard input to
the console. But thats all it will do. You cant interrupt the cp or
whatever caused the problem. I can make this happen easily by copying 
or uncompressing a 10Mb file.

The 1740 is configured in its standard 1540 compatibility mode,
with synchronous SCSI enabled, parity enabled, and disconnect
reconnect enabled. I have configured the kernel's 'high performance
disk driver' according to the documentation, using all the default
values. System also has a Wangtek 150Mb SCSI tape streamer, which is
not in use when the problem occurs.

Any ideas ?

Q2:
The Fujitsu 2266 has 1029 cylinders. Although the fdisk table only
caters for disks with up to 1024 cylinders, ISC's documentation says
that it will use the additional cylinders, if you try to allocate
them when partitioning the disk during installation. I had a mail
msg some time back from someone who said that this does not work, and
furthermore that by attempting to use cylinders >1024, the system will wrap
around to cylinder 0 and clobber the start of your disk (which would
be *serious*).

Anyone else experienced such problems ? It would seem unlikely to me
that ISC would state that such a facility works if there is a bug of
this order of magnitude in it.

Many thanks in advance,

-- 
- Colin Manning, cm%jet.uucp@ukc.ac.uk (world) OR cm@jet.uucp (UK only)
- Disclaimer: Please note that the above is a personal view and should not 
  be construed as an official comment from the JET project.