old modems & a packet switcher

tony writes: I don't remember the York Box specifically, but I remember JANET from my DECUS days. The York sounds just like an X.25 version of the HASPBOX with more modern cards (the HASPBOX dates from 1977 to 1982). It was an 11/03 (KD-11A?) or 11/23 (KDF-11) or 11/04, depending on exact vintage, with RAM and a DPV11 or similar (COM5025 UART), again, depending on vintage, all running a custom monolithic I/O front-end program that was downloaded once per phone call, and handled retransmission of flawed packets and routing to a local printer port, all without distubing the host PDP-11. It was a great boon the RSTS adminstrators to offload print jobs from the IBM mainframe. The pre-RSTS v8 print spooler ate gobs of CPU (later versions did as well, I suspect, but by then, there were more cycles to go around). The application software on the PDP-11 host saw a perfect data stream, blocked to 512 bytes per block, DMAed into memory, ready to chew on. Very efficient. A funny side note, when HASPBOX was replaced by COMBOARD(R), a 68000-based, single-board descendent, the serial I/O board often had more horsepower than the PDP-11 or VAX it went into (an 8Mhz 68K is rated at a nominal .6 MIPS, which compares favorably to a VAX 11/750 at .6 VUPs) It could be termed an I/O coprocessor at that level. Second funny side note: the original HASPBOX code, in PDP-11 MACRO, was converted to 68K assembler by TECO macros. the macros did over 90% of the work, humans did a quick desk check and fired it up. It was an amazingly clean migration, and a testement to how much the Motorola designers borrowed from DEC in terms of processor philosophy. Both CPUs rank up there in my top 5 to program (the 6502 and 1802 all competing for number one). 80x6 assembler sucks, in case anyone cares to hear. -ethan