SUMMARY: 600 w IPI and SCSI - DMA error

From: Kevin Sheehan {Consulting Poster Child} (
Date: Mon Jul 24 1995 - 11:37:26 CDT


DMA errors on the esp interfaces of a 600MP machine running 4.1.3DBE with
large SCSI and IPI disk farms.


Replies were mostly along the lines of SCSI problems in general, but
unfortunately that is not the problem. One hardware vendor consultant (who
chose to remain anonymous) said that the SBus does not do infinite re-runs,
and that they had noticed timeout problems with long VME cycles in their
SBus/VME converter. Another note was that there may be SBus starvation
problems with the SBus/MBus arbiter chip in the 600, but no specifics.

The customer doesn't want to upgrade to 4.1.4 as a pig in a poke, so unless
anybody has a good solid clue, we are down to nasty hardware debug...

        l & h,

Thanks to:

Brad.Walker@Corp.Sun.COM (Brad Walker) (Carlo Musante) (Frank Allan - Network Manager)

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