SUBS Machine

Van der Poel postulated a computer with only one instruction. Fifty years ago mainframe computers had 100 to 200 hard-wired instructions. RISC computers came along with fewer instructions.

Bt a computer with only one instruction? How useful could that be?

It turns out to be supremely useful on several fronts:-

(1) If memory is cheap, you can build a functioning microcomputer from parts ordered through the DEC handbook. NAND/Nor gates and the like.

(2) You can build an interpreter that takes in a hybrid of APL and FORTRAN and spits out a program that can be run on the SUBS machine. It follows that since you can simulate the SUBS machine in FORTRAN, you can run this single-instruction simulation on the single-instruction computer itself.

(3) Learn essential skills in the design and development of macros/

(4) Learn essential skills in the design and development of libraries of code.

(5) Learn why top-down program design is important

(6) Learn why bottom-up program coding is important.

(7) Learn what self-testing procedures are and how they can cut your program development time in half.

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