On Fri, Jul 24, 2020 at 2:37 PM Paul Koning <paulkon...@comcast.net> wrote:
> The right answer would be a tweak to the console emulation in SIMH pdp11. Mumble... Paul - I'm not so sure. While DEC used MARK a lot, there were places that used EVEN parity a lot also on PDP-11's (Lord how, I hated 20 mA current loop ;-) at least by the time of widespread RS-232C interfaces it was glass ttys and usually a full 8-bit data path. 7-bit with odd/even is defined this way: bits of data (count of 1-bits)8 bits including parity evenodd 0000000 0 *0*0000000 *1*0000000 1010001 3 *1*1010001 *0*1010001 1101001 4 *0*1101001 *1*1101001 1111111 7 *1*1111111 *0*1111111FWIW: I'm on a Mac and I run a program called 'Serial' that can do that; but I thought most of the programs that simulate a serial connection for the different PC/Windows system have similar options. Certainly that was true when I did it with DOS. Anyway, I think the 'right' answer for simh is to ask the user to use a serial emulation program that can generate any of: 8-bit no parity, 7-bit no parity, or 7-bits of data plus an 8th parity bit with any of the 4 parity options: odd, even, mark (aways 1) or space (always 0). Seems to me, simh should bring 8 bits into the simulated serial port and let the SW running on the system decide what it's going to do with it. I'm curious to hear what Bob thinks?
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