[Simh] PDP8, Adventure, and SIMH

[Rick Murphy]

At 07:28 PM 4/3/2013, Johnny Billquist wrote:
>On 2013-04-03 23:39, Rick Murphy wrote:
>>At 08:12 AM 4/3/2013, Johnny Billquist wrote:
>>>On 2013-04-03 14:03, Bob Supnik wrote:
>>>>PDP-8s by default came with ASR/KSR-33 teletypes, which were upper case
>>>>only (and the parity bit forced on). The default terminal option is
>>>>'KSR' to mimic that.
>>>>
>>>>When DEC began building its own terminals, like the LA36 and VT52, they
>>>>offered upper and lower case. The '7b' option is there for that.
>>>>
>>>>Note that if you SET TTI 7b, start OS/8 (at least the version I have),
>>>>and type dir instead of DIR, the command isn't recognized.
>>>
>>>I know that works for me, but it might be an issue with mark parity
>>>(which all old OS/8 software expects), or it might be an issue with
>>>CCL, which comes in many flavors.
>>
>>There's an OS/8 patch for KBM and CD to allow lower case input. It's
>>"LCSYS.BI" on the Diagnostic RK05 that Rick Moore built which is widely
>>distributed. UCSYS.BI restores the default operation.
>
>I should check that one out. Thanks.
>However, DIR is not a KBM command, but is something done by CCL. 
>Unless I'm really confused...

The thing giving you the "." prompt and reading the response is the 
Keyboard Monitor. It handles simple commands like "ASSIGN", "DEAS", 
"GET", "ODT", "R", "RUN", "SAVE", "START", and hands anything else off 
to CCL using the command line that KBM read. User input is uppercased 
before it's stashed into the input buffer.

With the patch, you can use lowercase much of the time in OS/8 but lots 
of CUSPs aren't lowercase tolerant.
         -Rick