p2-11, Part Two: Faster Than a Real PDP-11/40, With a Little PASM
The first post about p2-11 ended with the same computer fifty years apart, and the new one running “at a quarter of the speed”. On the Parallax forum , Chip Gracey asked whether that could be surpassed: “Sounds like you’re up against limits, but maybe there’s some fundamental matter that could be improved.” My guess was: not in pure OctoGo. The next morning, the guess has held, and the 11/40 is surpassed anyway. p2-11 runs its benchmark about one and a half times as fast as a real 11/40, and the recorded session with Unix V6 takes 45 seconds from ogo run to the last sync , where it took 95. Here it is, recorded on the board at real speed, in the default checked build at 160 MHz: That is ogo run , the four packs found on the card, the benchmark at 755,620 instructions a second, V6’s bootstrap, root logging in, and cc compiling hello, world, which runs and is removed again before two sync s. 8.5 of the 45 seconds are the build, the load, ...