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Old Programs

Paper TapeI have written lots of programs over the years and inevitably, some of them have since become obsolete, often because the computers for which they were written simply do not exist anymore.

Most of them are just gone, but a few have survived the moves from system to system for some reason. I don't know what to do with them, except putting them here, for posterity. ;-)

PDP-8 BASIC on Teletype Paper Tape

I can't show the actual programs, but here is a picture of the three remaining tapes of my first feeble programming attempts. Two are dated in the spring 1979 - one plays Mastermind and one computes prime numbers (probably in a very naive way). The third is not marked, but from the little I deciphered it might have been for some school project dealing with fuel consumption. The part visible in the picture reads:

   ... STRUKTIONER";
40 INPUT A$
50 IF A$="N" THEN 80
60 PRINT "INSTR."
80 PRINT
90 P...
.. PRINT
110 PRINT "BR[NSLEF\RB...

It's possible to read them manually, but it's tedious. (Can't do that with any modern media!) The storage capacity is 10 bytes/inch btw, or a little less than 400 bytes/meter. If I find a way to read these tapes again, I might put the programs here. (A USB paper tape reader, anywone? :)

MACRO-20 for TOPS-20

Although an assembler, the macro language was so powerful it was almost like C (but with the traditional assembler syntax of course ;-).

  • SEARCH.MAC is an implementation of Boyer-Moore's fast string search. Lots of features, very fast. I didn't call it grep because it doesn't have regular expressions. Written in 1986 and maintained until late 1990.
  • Writing a DES program for the PDP-10 was an interesting challenge. The PDP-10 addresses 36-bit words, and uses special byte-pointers to address bit fields within a word, while DES is definitely aimed at 8-bit byte addressing...
    • DES.MAC is the implementation of the DES encryption algorithm.
    • CRYPT.MAC is the main program, using DES.MAC.

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