ez-scsi speed settings and aic7890
Dennis J.A. Bijwaard
bijwaard at Speed.a2000.nl
Mon Apr 12 14:40:03 PDT 1999
Mike Bilow wrote:
> DL> There is nothing wrong with that configuration. The problem
> DL> appears to be memory corruption. When the CD-ROM is run at
> DL> full speed under NT along side the Ultra2 disk, you get
> DL> corruption as well. Because the linux ext2 filesystem is in
> DL> general faster than NT's filesystem, you see the same memory
> DL> corruption with lower speeds on the CD-ROM. Basically,
> DL> linux is faster and that makes it break with lower transfer
> DL> speeds. I would suggest you try swapping out the RAM and/or
> DL> CPU to see if the problem goes away.
Shouldn't I notice any other corruption when the memory or processor
is at fault?
I compiled a lot, kernels/kde-1.1/wine etc which I downloaded by cable
from the internet. But the programs all seem to run as expected.
I also tried 5Mb/s asynchronous on the aic7890 in linux, with the same
problems.
>
> I would like to take a flyer on this one, but I disagree with Doug's guess
> about memory corruption. I agree that the driver is not at fault, of course.
>
So do I, but I could do with some extra ram. This will give me the
change to
rule out this possibility, or get a replacement from the company where I
bought
the whole bunch.
> My guess is that the CD-ROM drive is bad. Running in the presence of an 80MB/s
> Ultra2 device might confuse it. If you can, I suggest that swapping the CD-ROM
> drive with, frankly, a better brand -- say, Toshiba -- might solve your
> problem. I would go so far as to say that, in my opinion, it is unlikely that
> Doug's suggestion about swapping RAM and CPU will have any effect.
Well Mike, let me tell you a secret. The same problem occurs on the
ricoh drive
when I read/compare an iso image on the aic7890. I did not test this
often because
the drive only supports 4 speed :-(
> You could probably stabilize the system by limiting the hard drive data rate,
> but that is not a real solution. Overterminating the SCSI bus, so that
> termination on the controller (which must be in the middle on your system) is
> enabled in addition to each end of the bus could help, too, although this is
> certainly not a recommended long term solution.
This seems a bit farfetched in my opinion. But thanks for the
suggestion.
--
Kind regards,
Dennis Bijwaard
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