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Playlist "Vintage Computing Festival Berlin 2022"

Who am I? CPUID on the PDP-8

Pontus Pihlgren

Portable software must adapt to peculiarities of the target platforms. Even variations within a "compatible" family of computers may require specific code. But how does a program identify which machine is executing it? In this presentation we will dissect, line by line, a subroutine written by the late Charles Lasner (CJL) as part of the Kermit implementation for the PDP-8 family of computers. The subroutine, "MACHINE", is capable of identifying all DEC PDP-8 models. Some familiarity with programming will benefit the listener, but the presentation includes the basics of PDP-8 assembly and the level should be approachable to most.