On Wed, Oct 7, 2020 at 12:07 PM Glen Slick via cctalk <cctalk@classiccmp.org> wrote: > > On Wed, Oct 7, 2020 at 8:37 AM Ethan Dicks wrote: > > > > On Wed, Oct 7, 2020 at 5:07 AM Peter Allan wrote: > > > RJE/HASP > > > 2780/3780 Protocol Emulator > > > > I used to do this with specialty hardware... > > > > http://www.bitsavers.org/pdf/softwareResults/Software_Results_Comboard_Brochure_1983.pdf > > > > There were also intelligent sync serial engines for this from other > > vendors, including DEC (KMC11, and probably a later one but the device > > name escapes me). > > I was curious about this DEC M8704 DMS11-DA that sold cheap a few days > ago. It has eight SMC COM5025 "Multi-Protocol Universal Synchronous > Receiver/Transmitter USYNR/T" chips: > > https://www.ebay.com/itm/373243388363 > > Apparently it can't do anything on its own. It needs to be connected > to a UNIBUS through a companion KMC11 processor board, which might not > be too common if someone wanted to put together a working > configuration.
I have very dim memories of that arrangement - it was definitely ordinary that you had a dedicated I/O processor to run multiple lines. Part of the salable benefit of the COMBOARD was having an 8MHz 68000 manage the actual protocol - it moved block file data to/from the DEC host via DMA. The M68K wrapped it up as needed, handled re-transmission, etc. Using a KMC11 is similar, IIRC, certainly at the bottom levels. -ethan -ethan