Decoding a punched paper program tape from 1975
#17650

I recently came across an 8 bit punched paper tape with some sort of program on it:

The tape has written on it "4/7/75 DRAW", which makes me think it's some sort of graphical program. Some minimal detective work revealed that the data was encoded in ASCII, with the high bit set for some reason? Anyway, the result is that I can get data off of the tape by manually typing in the zeroes and ones from the hole patterns, but that takes a very very long time. From what I've done so far (about 30cm of tape) I was able to decode the following:

The code is obviously BASIC, and from the top few lines you can see it's doing something with arrays and strings.

The top few lines before the BASIC code seem to be the output of a console where something was typed to load the program into memory and then write it out to the paper tape. The commands seem to match up with the command set of the TOPS-10 operating system on the PDP-10, which was actively used around that time and had a paper tape reader. The commands used in the minimal amount of BASIC I decoded seem to match the PDP-10 BASIC implementation as well.

I want to make a reader for this tape eventually, so I'll be working on that, and then maybe I can decode the whole program!

The instructions are the last resort.