SUMMARY: Can I use SBus Prestserve on MP670

From: Simon Shickman (
Date: Tue Mar 31 1992 - 19:32:06 CST

I got few more answers to my question:

>can I use a SBus Prestoserve Acceleretor in a MP670 or I must get a VME-bus

Thank you all very much.
From: (Hal Stern - NE Area Systems Engineer)

you can use an SBus board, and i'll say (unofficially) that's
the preferred way to go. the SBus board is faster than the
VME board.

due to addressing and cache design limits, not all possible
SBus <-> VME transfers are possible on a 600MP. you
can't go from an SBus master to a VME slave, which means
you can't use a VME prestoboard with SCSI disks (using
the unmodified driver) VME presto & IPI disks are fine, and
an SBus presto board works with both types of disks.

you can make the SCSI & VME presto combination work,
but you end up doing an extra bcopy() in the driver
since you can't set up the DVMA transfer. it costs
about 7% of your CPU to enable this mode.

From: (Ira Winston)

the sbus prestoserve works with scsi disks. you can also get a vme
prestoserve if you have IPI disks.

From: ( Bob Burleson )

You must use the SBus Prestoserve board to accelerate SBus devices. So if you
have scsi bus disks that you want to accelerate you must use the SBus Presto. If
on the other hand you want to accelerate a VME bus device, IPI disks, then you
must use the VME Prestoserve. We are using the SBus Prestoserve to acceltrate ou
scsi bus disks on our SUN 670MP and it work fine.

Simon Shickman
Computation Center				voice:	+972-2-584279
The Hebrew University of Jerusalem		fax:	+972-2-527349
Jerusalem 91904, ISRAEL				bitnet: simon@hujivms

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