>> I don't want to take this to far off topic, but where can you get 1742's
>> these days?  I can't find them locally anywhere.  Does Buslogic make a EISA
>> controller?
>
>they make two, the 742 and the 747, both of which are supported by
>NetBSD's 'bt' driver.  If i remember the specs right, the 747 is a
>fair bit faster than the 1742, and the 742 slightly faster, for some
>types of transfers, or something like that...

The 742 is an EISA bus master SCSI-2 controller with dual floopy.  It
uses single-ended passive termination. (Max 5MB/sec sync/async, 
33MB/sec burst)

The 747S is an EISA bus master FAST SCSI-2 controller with dual floppy
(including 2.88 MB support).  It uses single-ended active termination.
(Max 10MB/sec sync, 7MB/sec async, 33MB/sec burst)

The 747D is an EISA bus master FAST SCSI-2 controller with dual floppy
(including 2.88 MB support).  It uses differential termination.
(Max 10MB/sec sync, 7MB/sec async, 33MB/sec burst)

The 747 can offer a bit better performance than the 742 since it is
a FAST SCSI controller, but only with devices that support FAST SCSI.

The differential controller has a max SCSI bus length of 25 meters (standard),
while the single-ended controllers have a max bus length of 6 meters (standard)
Take note, though, that in practice single-ended FAST SCSI controllers 
have a limitation of more like 2-3 meters, though with good 
cables and devices you could probably stretch it further.

I have a 747S and am very happy with it.

	-Ted

--
Theodore S. Kapela
Polytechnic University
kapela@sirius.poly.edu


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