UniBone: Linux-to-DEC-UNIBUS-bridge, year #1

I *think* (and this is putting the wayback hat on) that the RH11 originally was the controller for the RS03 and RS04 fixed head disk drives. The dual Unibus was so you could put them on Unibus A for talking to the 11/45's main bus with data transfers ripping across Unibus B directly to the dual-ported memory on the 45. Thus one of the Unibus ports didn't need to worry about arbitration (it was the only thing on the bus) and could stream data from the (very quick) RS03/04's right into memory for the ultimate swap device. The 2020 takes advanatge of this with the dual unibus adapter, one talks to the chatty stuff like the DZ11's, the other has no arbitration issues as it sucks data down from the faster spinning RM03s without timeouts. One of my long term questions has been to see if a 2020 could talk to a RM80. It should be possible as the Massbus personality module talks to the bus at 3600 RPM just like the RM03, and they did manage to get the R80 to talk to the 11/730 with a dedicated memory channel connection (though maybe the R80 was heavily interleaved) C On 11/21/2019 9:14 PM, Noel Chiappa via cctalk wrote: