The Annotated VT100 Firmware

The VT100 terminal, launched in 1978, was DEC’s first ANSI-compatible terminal and their first that moved from discrete logic to a microprocessor, the Intel 8080. Slight modifications to the supported escape sequences were made for the cost-reduced follow-on models, the VT101 and VT102, and those changes became the definition of “VT100 compatible,” in DEC’s internal Video Systems Reference Manual, used for the next 15 years. This set of documents takes the original 8 KiB firmware for the VT100 and attempts to explain the workings. There is a fully annotated disassembly with links to the Technical Manual and the print set. Sections Why Disassemble the Firmware? How the Disassembly was Produced The Disassembly Bugs and Oddities Awnty, an 8080 coverage checker Resources elsewhere