DEC PDP-10

Boots a from-scratch 36-bit DEC PDP-10 (KA10) and prints HELLO, WORLD! on the console teletype, then echoes every character you type (uppercase, like a real Model 33). Click the screen first so it captures the keyboard, or tap the on-screen keys. Open the debugger to single-step the 36-bit CPU one instruction at a time, watch the PC and the sixteen accumulators (each shown as two 18-bit octal halves) change, set breakpoints on the program counter, and read core memory as octal disassembly.