On Wed, Jul 15, 2015 at 7:05 AM, Jay Jaeger <cu...@charter.net> wrote: > ...though I have not actually checked. The B5000 had IO processors as well.
Not quite, the B5000 and B5500 arguably had DMA channels (up to 4 of them), but not independent IO processors (with their own machine code) that were seen on the later follow-on B6500 family (B6700, B7700) with the DCP (which had an associated definition language NDL). B6500 peripherals (like Datacomm) were back-ported to the B5700 (a re-badged B5500 with optional B6500 peripherals) seemingly as a stop-gap due to delays in delivering the B6500.
