[simh] RSTS processor identification

On Fri, Mar 5, 2021 at 6:33 PM Paul Koning via cctalk <cctalk at classiccmp.org <mailto:cctalk at classiccmp.org>> wrote: I would have liked better comms.? The USART has such a tiny FIFO that you can't run it at higher than 9600 bps even with the J-11 CPU.? At least not with RSTS; perhaps a lighter weight OS can do better.? The printer port is worse, that one can't run DDCMP reliably at more than 4800 bps.? I normally run DDCMP on the PC3XC, which is a 4-line serial card that uses two dual UART chips (2681?) with reasonable FIFO. There seem to be a great many models of Unibus and Qbus multi-port async serial boards, which present different register-level interfaces, e.g. for Unibus, DH11, DHU11, DJ11, DM11, DZ11 . Which ones are considered "best", for each bus, for use with a multitasking OS like RSTS/E or RSX-11M+?