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From: iverson@lionheart.com (Tim Iverson)
Subject: Re: FreeBSD 2.0: SCSI problems
References: <A0045.95Jan12111714@roxi.rrz.Uni-Koeln.DE> <daves.10.000182BB@interlog.com>
Organization: Lionheart Software
Date: Sun, 22 Jan 1995 13:06:41 GMT
Message-ID: <D2t5r5.BwA@lionheart.com>
Lines: 40
In article <daves.10.000182BB@interlog.com>,
David Shadoff <daves@interlog.com> wrote:
>In article <A0045.95Jan12111714@roxi.rrz.Uni-Koeln.DE> a0045@roxi.rrz.Uni-Koeln.DE (Jochen Roderburg) writes:
>>One system has an old ESDI boot disk and an Adaptec 1542B adapter with an
...
>> adapter not taking commands.. frozen?!
>> Debugger("aha1542") called. AGAIN
...
>I went through some of the same problems as you - 1542B controller with those
...
>Parameters for my problem: the motherboard was a 'PC CHIP' chipset, TI
>486DLC, with AHA-1542B. Tried several drives, ALL permutations of
>termination, and several cables. New motherboard (Intel 486DX2-66/SIS
>chipset) solved all problems.
It sounds like the newer drivers are using more aggressive bus on/off
timings. This can improve performance. It can also cause a system that
should work to completely fail.
The older Adaptec cards also have problems running with ISA bus speeds
greater than 8Mhz. At one time, there were BusLogic cards that would run
at speeds of up to 16Mhz, but I'm not sure of the current state of affairs.
Other than patching the driver, the only thing that you can do without
replacing hardware, is to fiddle with the CMOS settings. Setup the ISA in
it's slowest, most compatible mode, enable hidden refresh if you have it,
etc.. Also, set the *ISA BUS* transfer rate on the adapter to it's slowest
setting (5MB/s). This might help.
>as though many people thought such a bug was impossible - that it must be a
>hardware problem.
Actually, the person who wrote the driver should have known better than to
use aggressive timings. BTW, Adaptec's default timings DO NOT WORK on
anything but DOS systems. DOS doesn't multi-task, and thus won't run
floppy and SCSI simultaneously.
- Tim Iverson
iverson@lionheart.com