M-1100 Apr61

This interoffice memorandum from April 26, 1961, provides operating instructions for the DEC TP-1 Punch Test Program on the PDP-1. It details two main modes for testing the paper tape punch and reader: "General Test" and "Test Word Mode."

I. General Test:

• To Punch Test Tape:

  • Set Sense Switch #1 down.
  • Start the program at address 100 (for punch #0) or 112 (for punch #1).
  • The program will punch a comprehensive pattern:
    • Alphanumeric mode: 10 lines of all ones, then 10 lines of all zeros (repeated).
    • Numeric sequences: 0,0 through 0,376; then 377,0 through 377,376.
    • Binary mode: Numbers 0 through 77.

• To Check Test Tape:

  • Load the newly punched test tape into the reader, with the reader set to 200 characters per second (c.p.s.).
  • Set Sense Switch #1 up. The program will begin reading and checking line by line.
  • If no error: The program halts with the Program Counter (PC) holding 412 (after checking for a single line of feed).
  • If error: The Accumulator (AC) will indicate incorrect bit(s) (bits 10-17 = holes 8-1), Input/Output (IO) will show the erroneous line number, and PC will be 537. Press "continue" to check the rest of the tape.
  • To recheck the tape, start at address 261.

II. Test Word Mode:

• To Punch Test Tape (Alphanumeric Mode):

  • The program alternately punches the right half (bits 10-17) then the left half (bits 2-9) of a "test word."
  • It punches 19 pairs of these lines, followed by a 250 ms delay, repeating indefinitely until manually stopped.
  • Start at address 220 (for punch #0) or 224 (for punch #1).

• To Punch Test Tape (Binary Mode):

  • The program alternately punches the left half (bits 0-5) then the right half (bits 9-14) of a "test word."
  • The repetition and delay are the same as in alphanumeric mode (indefinite, manual stop).
  • Start at address 222 (for punch #0) or 226 (for punch #1).

• To Check Test Tape:

  • Load the tape into the reader, set to 200 c.p.s.
  • Ensure "Test word switches" remain undisturbed from when the tape was punched.
  • Start at address 450 (if the tape was punched in alphanumeric mode) or 500 (if in binary mode).
  • If no error: The program halts upon finding tape feed, with PC = 537 and IO = 200.
  • If error: The error indications are the same as described for the General Test (I.b.4).
  • To recheck the tape, repeat the start procedure (II.c.3).