A family rather than one specification
The Computer History Museum identifies the PET as a 1977 6502-based machine used early in schools and homes. Surviving museum records also show why model qualifiers matter: a Science Museum Group PET 2001-8-BS records 8 KB of RAM, while a Smithsonian PET 2001 record identifies an initial 4 KB configuration. The Atlas therefore treats PET memory, keyboard, board, and ROM statements as model-specific facts rather than family-wide constants. [1] [2] [3]
Memory and the BASIC environment
The 1978 PET 2001-8 manual maps an 8 KB configuration across addresses $0000–$1FFF. It reserves the first 1 KB for system use and reports 7,167 bytes free to BASIC. The same manual distinguishes system ROM, user RAM, input/output memory, and screen memory, and describes expansion checks up to 32 KB. These details explain one documented configuration; they do not redefine every later PET. [4]
Interaction, storage, and evolution
Display, keyboard, cassette devices, and attachable peripherals were coordinated by the 6502 in the documented PET 2001-8 system. The built-in cassette mechanism was a normal program-loading route. Separate service archives for early PET 2001 boards and later 4016/4032 material show how the family evolved and why board-level claims require their own evidence. [4] [5] [6] [7]
Related systems
Sources
- Commodore PET home computer, 1977 — Computer History Museum
- Commodore PET 2001-8-BS personal computer, 1977 — Science Museum Group
- Commodore PET 2001 Microcomputer — Smithsonian
- PET 2001-8 Personal Computer User Manual (1978-10)
- Commodore PET memory and storage history — Computer History Museum
- PET 2001 service documents and schematics — Zimmers.net
- PET schematics and technical-reference index — Zimmers.net