SIMH LGP-30 Progress.
billdeg at buzz1.com
Tue Feb 10 23:03:11 CST 2015
Update on my attempts to bootstrap the SIMH Royal Precision Electronic
Computer model LGP-30.
I have been able to get through a lot more of the simulator-equivalent
processing steps to match the input of the bootstrap programs via the
native Flexowriter. I have been able to discover the syntax and basic I/O
via trial and error, and a lot of reading. I believe that loading the
bootstrap manually is a must; one cannot use or create tapes otherwise.
Most SIMH's have some kind of software guide, the LGP-30 has none. I don't
think this SIMH has the bootstrap pre-loaded. I am unaware of anyone who
is using the SIMH simulator, although I have seen two non-SIMH LGP-30
simulators. One is in German.
In order to enter instructions into memory I first learned how to translate
code from the various actual papertape sources, for example...
"flexowriter entry"> 6300 P 0000'
sim> d -a 6300 10000000
where 6300 = memory loc in drum memory, 1000 = P, 0000 = accumulator
address (?). You can't store a "P" or "p" in memory. You have to convert
to its Flexo binary equiv. Same goes for all instructions in the LGP-30
repertoire. The hardest part is finding ways to enter Flexowriter key
input via a modern keyboard, using SIMH commands.
It's all pretty slow going to patch together what I think would be a
workable bootstrap install process, but I expect to have to try a number of
variations before I get any response from the machine. I have a bootstrap
but the hard part if the Flexowriter emulation. Who knows, maybe I will be
able to contribute a software guide from all of this. I will document what
I find and post on my web site, vintagecomputer.net.
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