VAXstation 3100 history (Was ... different)

From: Dave McGuire <mcguire_at_neurotica.com>
Date: Wed Dec 1 10:47:19 1999

On Wed, 01 Dec 1999, Roger Ivie wrote:
>My original design concept for the Firefox QBus Adapter Module involved
>having a dual-ported memory between the MBus and the QBus. The device
>drivers would copy data to and from this memory before or after performing
>DMA, as appropriate. This would have worked nicely and provided acceptable
>performance. However, I made the mistake of describing the arrangement
>to VMS people as "just like the MicroVAX I"; since the MicroVAX I doesn't
>have a scatter/gather map, the device driver has to do this to cover that

  Yuck.

>lack. I was rudely informed that VMS no longer supported the MicroVAX I,
>and good riddance.

  Oh my. I am sadly misinformed, then. I apologize. I hadn't heard about the
removal of -I support.

>So, the FQAM wound up being a really ugly and slow QBus adapter that worked
>much more like the traditional QBus adapter.

  Bummer...

               -Dave McGuire
Received on Wed Dec 01 1999 - 10:47:19 GMT