From: Teemu Rantanen (tvr@cs.hut.fi)
Date: 10/01/92


From: tvr@cs.hut.fi (Teemu Rantanen)
Subject: Re: Slow SCSI Disk performance.
Date: 1 Oct 1992 22:57:45 GMT

In article <3775@ra.nrl.navy.mil> eric@tantalus.nrl.navy.mil (Eric Youngdale) writes:
> the end of this message. I would guess that the I/O speed would
> roughly double with these patches inserted. For the aha1542, the
> performance increase will be even more, because I changed some timing
> values.

   I tried scsi performance of 0.98 with and without this patch.
   Performance was the same (as it has always been), approximately
   57k/sec when reading a big file. Write performance is about the
   same than read performance.

   Also BUSON / BUSOFF timing changes caused 'Over/Underrun -
   retrying' messages when writing to both floppy and scsi-disk at the
   same time.

   I have an Adaptec 1542B controller and an (old) Priam 738 disk with no
   track buffering.

   How much longer for new scsicode that supports many outstanding
   requests?

                                        Teemu