[Simh] SIMH console settings for escape sequence support

[Johnny Billquist]

Um. What does 7B and 7P stand for here? They are not "normal" 
designation for 7 bits with some parity... The letters I know of are N - 
None, S - Space, M - Mark, O - Odd, E - Even.

And if you are using anything that manage to print something visible 
when outputting a NUL, that sounds like something broken somewhere else.

Sounds like the current simh code is trying to cover up when people have 
an error somewhere else in their setup?

	Johnny


On 2016-01-01 21:53, J. David Bryan wrote:
> On Thursday, December 31, 2015 at 16:19, Mark Pizzolato wrote:
>
>> The PCHAR mask is actually only used when the terminal device
>> (console) is in 7B or UC mode.
>
> That should read "7P" mode, not "7B" mode.
>
>
>> In the interest of fewer problems in the future for various folks, the
>> default PCHAR mask has now been changed to include ESC and ENQ in
>> addition to the previous BEL, BS, TAB, LF and CR.
>
> The intent of 7P mode is to mask off non-printing characters -- basically,
> those not interpreted by a Teletype.  By contrast, 7B mode allows all 7-bit
> characters through.
>
> Some simulated systems output control characters, e.g., NULs as pads, which
> wind up printing junk characters on the screen in 7B mode.  Also, some
> simulated programs rely on control characters not printing when editing
> command lines for example.  These rely on mode 7P to work properly.
>
> Rather than changing the non-printing character mask to allow non-printing
> characters to print, it would make more sense to change your device default
> from 7P to 7B.
>
>
> On Friday, January 1, 2016 at 15:03, Paul Koning wrote:
>
>> More... it occurs to me that many operating systems and/or applications
>> do their own filtering of control characters, so in fact a good setting
>> for the pchar mask is all ones.  In other words, 37777777777 octal or
>> ffffffff hex depending on the simulated machine.
>>
>> I wonder if that should be the default, instead of 23600.
>
> That would make modes 7P and 7B identical.  Again, changing the device
> default would be better.
>
>                                        -- Dave
>
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-- 
Johnny Billquist                  || "I'm on a bus
                                   ||  on a psychedelic trip
email: bqt at softjar.se             ||  Reading murder books
pdp is alive!                     ||  tryin' to stay hip" - B. Idol