low-end vaxen and unix

allisonp at world.std.com allisonp at world.std.com
Sat Jan 30 07:06:28 AEST 1999

On Fri, 29 Jan 1999, Pat Barron wrote:

> As I recall, you can attach an external SCSI hard disk to a MicroVAX 2000,
> and Ultrix will be able to use it, but you can't boot from it.  The
> Centronics expansion port really is a SCSI port, even though it was never
> billed as such (and the TZK50 tape drive really is a SCSI drive, and you
> can use it on other systems that have SCSI - not sure why you'd want to,
> though....).

The centronics is electrically scsi and uses the NCR scsi chip (5380) but
there is nothing in the boot-diagnostic rom that supports it save for the
TK50FA version that has an oddball device protocal.  If you boot from
floppy or RDxx disk and have a driver that supports VS200 scsi properly it
can be used for expansion.  There are however issues in that the hard disk
interface and the SCSI chip use the same DMA channel and it would cause
some performance degrdation.

The port however is not for centronis printer as dec used serial
interfaced printers.

 > 4.3BSD (and its variants) for the VAX has no SCSI support at all, so
> you're out of luck if you want to use SCSI disks on a MicroVAX under 4.3.
> --Pat.

Tha is what the socalled qasijarius project is supposed to fix.


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