Seeking enlightenment regarding Bus Adapter Purges on Unibus VAXen (and their ilk)

Ethan Dicks ethan.dicks at
Fri Sep 6 16:19:22 CDT 2019

On Fri, Sep 6, 2019 at 4:32 AM Matt Burke via cctalk
<cctalk at> wrote:
> I'm not sure if the adapter needs to request the purge at the end of
> each block transfer. The driver may do this anyway but I'll have to
> check the source listings.

I would definitely check source listings.  Also, check BSD/Ultrix
_and_ VMS.  I guarantee they don't do everything the same way (case in
point RB730 controller initialization) but both will be insightful.

My own Unibus (and Qbus and VAXBI) experience is with comm drivers not
storage drivers so I don't have any insights on block transfers and
purges, unfortunately.

I'm excited for the results of this.


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