19 Nov
2005
19 Nov
'05
5:06 p.m.
From: "Allison":
Nominal PDP-8 use was short BIN loader hand toggled
in. Load bin
tape that contains small BIN format program or loads the RIM
loader for more complex programs (basic, focal). BASIC would
then read an ascii program tape.
It's a nit, but you have the roles of BIN and RIM reversed in
this paragraph. You also omitted a discussion of the checksum,
field setting, and comment features allowed in a BIN tape :-).
For those who care, BIN tapes have an extra 'data' pair at the
end which forms a checksum. Bytes with both of the most significant
bits set use the next three bits to select which bank or 'field'
is loaded. And arbitrary 'comments' may appear between rub-outs
(which have all bits set). RIM tapes have none of these features.
Both BIN and RIM tapes use leader-trailer with just the MSB set.
There are at least two versions of the BIN loader. I don't know
offhand if the older BIN loader supported all the features or
not.
Vince