This emulates CSIRAC, the 1949 machine that was Australia’s first computer, right down to the six monitor tubes that drew its registers as green traces and its store as grids of green dots. It ships with the machine’s own library tapes, numbers and all, and rather than reimplementing Interprogram it feeds the original 1960 compiler tape — Geoff Hill’s plain-English-ish language, Australia’s first high-level one — straight into the emulated machine. Free, no plugins, just a browser tab.