[Simh] pdp11 - console input with high bit set

[Rich Alderson]

> From: Johnny Billquist <bqt at softjar.se>
> Date: Sat, 25 Jul 2020 00:58:08 +0200

> I would have to disagree with that. All older PDP-8 software is 
> definitely using MARK parity, not EVEN. Both on input and output. 
> (Sortof annoying if you aren't expecting it.)

> The ASR33, as configured by DEC, was normally also set up with MARK 
> parity, which is probably the reason all software expected it.

> Actually, older PDP-11 software is also expecting MARK parity. Lots of 
> the older diagnostics, for example.

> I wouldn't know about older PDP-10 software, but it would be a little 
> surprising if they did things differently than PDP-8 and PDP-11.

Hi, Johnny,

On the PDP-10, the rule was "Be strict in what you send, and generous in what
you accept." The standard was to send 7E1, and anything which could be made
7-bit on input was good (so 8N1 was popular).

                                                                Rich

Rich Alderson
ex LCM+L
simh at alderson.users.panix.com