On Fri, Nov 22, 2019 at 6:39 AM Noel Chiappa via cctalk < cctalk@classiccmp.org> wrote:
> So I think all our questions are answerered (except for the [RH11]-AB/-C > difference > issue). > One version of the RH11 added a small FIFO (called a "silo" by DEC, IIRC) in the data path. I don't recall which suffix that was, nor whether it was the version used in the KS10. Presumably the reason for the FIFO would be to help disks work reliably on relatively "low-end" systems that can't wire the RH11's Unibus B to dual-ported memory. Since the KS10 has separate UBAs for the disks and tape, I wouldn't expect it to need the FIFO version of the RH11 unless there were problems with latency arbitrating for the KS10 bus. I would imagine that DEC gave the UBAs priority over the CPU.
