Imlac: add support for Alpha machine#468
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pkoning2 merged 8 commits intoopen-simh:masterfrom Aug 17, 2025
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I understand someone called Bob Shannon has or had an PDS-1 Alpha serial number 2. It might be worthwhile trying to contact him about verifying some theories about the hardware. |
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Here is a video: https://youtu.be/fj6-XjxbYOs |
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"load -s" loads a "special tty" image file, just like a plain "load" will. An unknown switch will raise an error.
"load -p" loads a paper tape image.
This adds new modifiers to the CPU device: 4k, 8k, and 16k.
Details figured out by Zachary Harper @sparky-z from reading the listing "FREEWAY CROSSING PROGRAM".
Paper tape image provided by Zachary Harper @sparky-z.
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The Imlac "Alpha" machine was an early PDS-1 model with less versatile hardware graphics. The updated model was called a "Graphics" machine. The most interesting - or indeed only surviving - application for this model is the Freeway (Crossing) game. The game code is part of this pull request.
CC @sparky-z @jdersch @tuban