SCSIS driver speed

[Brad Lineberger]

Just for a bit of trivia, I thought I would post some SCSI speed differences
we have noticed between SCO XENIX version 2.2 as distributed by ACER,
and MICROPORT UNIX version 3.0.e.1.

The SCO driver apparently was written by a third party firm, as it didnt
appear to contain SCO copyright information.  I think this is the firm
that wrote the SCSI driver for ADAPTEC.  I fully admit I cannot be sure of
this.

The MICROPORT driver was written inhouse from the ground up.  This may
or may not be an advantage.  Please note that the driver was later updated
to support SCSI tape, this is not the driver we observed though.

                                                                 
The "gist" of the observations is that both implementations of the SCSI
device drivers (SCO and uPORT) *SMOKED* (pardon the informality) their
ESDI and RLL counterparts.  We were VERY impressed with the speed improvements
over our ESDI system.  The ADAPTEC controller we were using apparently 
can handle many IO requests simultaneously, and this made compiling on
multiple sessions MUCH faster. 

The speed difference was so great that our MIS manager decided to cut
our losses COMPLETELY with ESDI and hit the scuzzy trail.  Im sure their
are some ESDI fans out there, so I would like to state clearly that these
are only individual observations, and not part of some vast, organized study. 

On a side note, the uPORT scsi driver seemed to handle Multiple IO requests
with much greater efficiency than the SCO driver.  We noticed this when
compiling 3 programs, uncompressing news, and playing a few games of
TETRIX on other sessions (grin).  In this environment, the uPORT driver really
shined. 

PS The test machines were an ACER system 15, and a COMPAQ 386/20, using
an ARNET Intelligent 8 port serial board, and 8megs of memory on each
machine. (And an ADAPTEC AH1540A controller).. Please note we did try 
each driver on each machine.

Just a bit of trivia for the driver-adicts out there..


-- 
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Brad Lineberger 			Plan: None (Dont use BSD or ultrix)
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