[Simh] pdp11 - console input with high bit set

[Clem Cole]

On Fri, Jul 24, 2020 at 2:37 PM Paul Koning <paulkoning at 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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