Reproducing old machines with newer technology

Nigel Williams nw at
Sun Jul 19 01:26:38 CDT 2015

On Wed, Jul 15, 2015 at 7:05 AM, Jay Jaeger <cube1 at> 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.

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