31 Oct
2004
31 Oct
'04
5:56 p.m.
Dan Lanciani wrote, quoting Charlie Root:
|Are full installation and user guides for Edusystem-20 around?
I don't recall seeing guides for individual systems (and it seems to me
there probably are some, a.k.a. teachers' guides and such), but they're
all documented reasonably well in DEC's _Edusystem Handbook_ (1973). The
noble Mr. Kossow has got a copy up at Bitsavers:
http://bitsavers.org/pdf/dec/pdp8/EduSystemHandbookJan73.pdf
I'm pretty sure I still have the Edusystem
Handbook around somewhere. I
think that has all the necessary information because I was able to use it
to start from scratch (toggle in the initial loader, etc.) a couple of times
in high school. Didn't the Edusystem tapes modify the RIM loader to start
themselves or such? Once they started the interactive configuration dialog
really didn't need any extra documentation.
They did indeed start themselves from the RIM loader - they loaded a BIN
loader in the first few feet of tape, and the final instruction loaded
from RIM forces a jump to the new loader; that loader,
in turn, loaded the
body of the program, and jumped to the Edusystem initialization
routine
when no character had been read from the tape for one second or so (e.g.,
once the tape had run out of the reader). It was a simple and clever
little trick. I disassembled it once to have a look at it, about, oh,
twenty-five years ago. A little frightening to remember it with such
clarity. :)
-O.-