Talk:Installing SITS on SIMH
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MB11
Noel, have you ever heard about an MB11 device? It's described like this in SITS:
;MB11 MAR AND HISTORY REGISTER MBCSR=170000+0 ;CONTROL AND STATUS MBXHGH=MBCSR+2 ;HIGH BITS OF X REGISTER MBXLOW=MBCSR+4 ;LOW BITS OF X REGISTER MBYHGH=MBCSR+6 ;HIGH BITS OF Y REGISTER MBYLOW=MBCSR+10 ;LOW BITS OF Y REGISTER MBHHGH=MBCSR+12 ;HIGH BITS OF HISTORY REGISTER MBHLOW=MBCSR+14 ;LOW BITS OF HISTORY REGISTER MBHCNT=MBCSR+16 ;HISTORY MEMORY COUNTER ;BREAK VECTOR MBBRV=374
I have not found any documentation, e.g. on Bitsavers. Larsbrinkhoff (talk) 11:37, 11 October 2022 (CEST)
- I have never heard of it. I have a near-complete set of PDP-11 fiche, which contains all sorts of unusual things which are not available online, and it doesn't have it, in any section, either. I did a Web search on 'MB11 PDP-11' (and similar things), with no results there either.
- Mx1[01] in DEC naming usually refers to memory of some kind (MA10, ME11, etc), but the registers you show there don't look like ordinary memory.
- So I'd guess it's some MIT home-rolled peripheral; given the X-Y 'MAR' (usually means 'memory address register), maybe some kind of graphical thing?
- Probably your best bet is to contact a SITS hacker and see if they remember. Radia is still with us; who else worked on SITS? Oh, you might try looking at AI Lab publications on SITS, to see if they mention an MB11; as a hand-rolled peripheral, it should have been mentioned. Jnc (talk) 14:54, 11 October 2022 (CEST)
- Thanks it's good to know it probably wasn't a DEC device. I have the impression Ron Lebel was the head Logo programmer. I have been in touch with him and Radia, but understandably they don't remember much. There was also Bruce E Edwards, who I have not been able to track down. Larsbrinkhoff (talk) 15:39, 11 October 2022 (CEST)
