IBM 1401

Boots a demo program that moves three banner lines from core storage into the 1403 print area and prints them, then idles with the PROCESS lamp lit. Toggle Sense Switch G (on-screen console or the G key) before Reset to print a fourth line. Open the debugger to single-step the 1401, watch the I-address advance through the variable-length instructions, set breakpoints and word-mark watchpoints.

Boots a demo program that moves three banner lines from core storage into the 1403 print area and prints them, then idles with the PROCESS lamp lit. Toggle Sense Switch G (on-screen console or the G key) before Reset to print a fourth line. Open the debugger to single-step the 1401, watch the I-address advance through the variable-length instructions, set breakpoints and word-mark watchpoints.