Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!tut.cis.ohio-state.edu!ucbvax!decwrl!decvax!ima!mirror!frog!rmk
From: rmk@frog.UUCP (Rick Kelly)
Newsgroups: comp.sys.amiga
Subject: Re: Version of driver for StarboardII SCSI module?
Summary: SCSI drives and interleave
Message-ID: <1538@frog.UUCP>
Date: 21 Jun 89 04:57:00 GMT
References: <41688@bbn.COM>
Reply-To: rmk@frog.UUCP (Rick Kelly)
Organization: Charles River Data Systems, Framingham MA
Lines: 39

In article <41688@bbn.COM> denbeste@BBN.COM (Steven Den Beste) writes:
>I've got a Starboard II loaded with RAM, and I just picked up a SCSI module for
>it for my two HD's. One of them is an ST277N.
>
>I've got it working, and by using FFS and by extensive playing with interleave
>factors I've managed to get the fastest transfer speed reported by "diskperfa"
>to the not-very-impressive value of 70K. I have yet to try their speed-up
>option that disables checking, but I don't anticipate it will buy me much.
>[Believe it or not, I get my best performance with an interleave of 10.]
>
>Several people here on the net have claimed they got transfer speeds above 200K
>with the ST277N. The only thing I can think of that might yet be my problem is
>that I might have an old version of the driver. (Or maybe a new, broken one.)
STUFF DELETED ...
>
>Steven C. Den Beste,   BBN Communications Corp., Cambridge MA
>denbeste@bbn.com(ARPA/CSNET/UUCP)    harvard!bbn.com!denbeste(UUCP)


The SCSI command set does not actually contain any modeselect commands
for format interleave.  When you do a low level format on a SCSI drive
you are really telling the SCSI driver to tell the hard disk to execute
its own format program.  Seagate has taken some of its older ST-506
drives and replaced the controller board on the bottom of the drive with
a SCSI controller.  Transfer rate is almost always affected by the SCSI host
controller on the system bus and the driver software provided.  The Starboard
has been around for a while, and it is not the most efficient (if you want
to really slow down try a Tiny Tiger).  The interleave commands that you send
to the drive are affecting the Starboard and the software driver, but the
hard disk will always have an actual interleave of 1.


Rick Kelly
Test Engineering
Charles River Data Systems
983 Concord St.
Framingham, Massachusetts 01701

508-626-1011