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From: allred@ut-emx.UUCP (Kevin L. Allred)
Newsgroups: comp.sys.ibm.pc,comp.unix.questions,comp.unix.wizards,comp.unix.xenix,comp.unix.microport,comp.unix.i386
Subject: Re: scsi rll trade off questions?
Summary: DMA jumpers Seagate scsi BIOS
Keywords: scsi rll hard disk compatability
Message-ID: <15064@ut-emx.UUCP>
Date: 10 Jul 89 19:39:35 GMT
References: <14978@ut-emx.UUCP>
Organization: UT-Austin, Dept. of Chem. Engr
Lines: 35

In article <14978@ut-emx.UUCP>, allred@ut-emx.UUCP (Kevin L. Allred) writes:
> I had pointed out to me that Segate has recently started marketing a
> low cost SCSI addaptor (ST01 and ST02) suitable for use with its
> ST296N 80MB hard disk.  This combination reportedly offeres about 750
> KB/sec transfer rate, which is comparable to the 1:1 interleve RLL

My questions seem to have raised a bit of interest and varied reaction
from several respondents.  In brief the key points of the responces
have been (focussing on the ST01 or ST02 rather than the ST296N):

1)  Spintest and Coretest recorded transfer rates of about 450 KB/sec.
2)  Spintest may not fairly report SCSI speeds (huh?).
3)  BIOS can make a big difference -- >800 KB/sec for 3rd party BIOS.
4)  Jumpering on the controller makes a difference (XT vs AT?)
    transfer rates jumped from 500KB/sec to 750KB/sec.
5)  ST01 and ST02 do not support DMA transfers.  Under Unix (DOS?)
    simultanious disk I/O with serial transfers can loose characters.

Is anyone familiar enough with the ST0x controller to respond about
the true capabilities of the ST0x controllers -- Seagate are you
listening?  If anyone can forward this on to some one there it would
be appreciated.

Item 5 in the list above is the current biggest concern to me.  If the
ST0x is not a DMA device what happens when I try to run software like
zmodem downloads that want to do serial and disk I/O simultaneously?

By the way, how can I get Spintest or Coretest?  I would like to get a
copy to benchmark whatever combination of disk and controller I end up
buying?
-- 

	Kevin Allred
	allred@emx.cc.utexas.edu
	allred@ut-emx.UUCP