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Using the GT40

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Lars Brinkhoff edited this page Jul 10, 2023 · 4 revisions

The AI lab had a GT40 attached to terminal line T34. The GT40 is a PDP-11/05 with a VT11 vector display controller, a CRT display, a keyboard, and a light pen. SIMH can emulate a GT40 and attach to a PDP-10 emulator terminal line.

When booted, the GT40 will run from the VT11 ROM. The ROM has very minimal terminal functions: it will display characters received from the PDP-10, and send keyboard key presses to the PDP-10. There are also reset and software upload functions. The ROM software by itself does not provide a usable terminal.

To use the GT40 with ITS, log in with ^Z and start GTLOAD to upload software. There is a Datapoint emulator called VT07. When the GTLOAD prompt * appears, type the filename GT40;VT07 and type enter. The upload will take a long time: one or two minutes. When the terminal emulator starts, it will type out "ITS IN OPERATION" at which point the GT40 can be used much like a Datapoint except it has additional lower case characters.

VT07 can also accept graphics commands. This facility can be used by Lisp and SUDS.

There is some other GT40 software. To run something else, restart the GT40 (emulator) and run GTLOAD again.

  • Lunar Lander: GT40;GTLEM BIN
  • Spacewar: GT40;SW BIN<
  • Minimal debugger: SYSBIN;URUG BIN
  • CONS console: CONS;CCONS BIN

The robotics lab also had a GT40, attached to T40. Most of its software has been lost, but there is a Spacewar game that can be run: https://github.com/pdp11/mit-gt40-spacewar

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