Talk:IMP interface

DR11C

Re DR11C. I peeked at the driver in 2.11BSD and I think it said Unibus. But it was only a brief glance. Larsbrinkhoff (talk) 10:11, 15 March 2018 (CET)

Hey, this mentions UNIBUS: [1] Larsbrinkhoff (talk) 10:19, 15 March 2018 (CET)

Huh? That page talks about the IMP11-A, the DEC CSS thing.

Anyway, for the SRI thing, it was possibly both, actually. What it was was an SRI board that took the bit-stream from the IMP, doing the host-IMP harware protocol ('there's your bit', etc), and converted it to words, which it shipped over a parallel interface to a standard DEC DRV11 card. I'm pretty sure the QBUS DRV11 and UNIBUS DRV11-C had the same parallel port spec, so you could probably have plugged the SRI card into a DR11-C instead of a DRV11. Since the DR11-C/DRV11 are programmed I/O, they wouldn't have had the performance of the others, which were DMA, which is probably why UNIBUS machines tended to go with the DEC/ACC interfaces. Jnc (talk) 15:55, 15 March 2018 (CET)

Sorry, wrong link. This is better: https://www.retro11.de/ouxr/211bsd/usr/man/cat4/sri.0.html

Yes, I see now DR11-C is the name a parallel interface. The BSD drivers use the Unibus device to talk to the IMP interface.

Here's a manual for the IMP interface: http://www.dtic.mil/dtic/tr/fulltext/u2/a037212.pdf Larsbrinkhoff (talk) 08:36, 16 March 2018 (CET)