The original Commodore PET arrived with much of the equipment a computer owner otherwise had to find separately. Its nine-inch monochrome screen, keyboard and cassette recorder shared one cabinet with the computer. Switch it on and BASIC was ready. There was no television to tune and no language tape to load.
Writing in Creative Computing in July–August 1978, Ludwig Braun reported that Commodore had been delivering PETs since about September 1977. He listed $595 for a 4K machine and $795 for 8K. Those are prices for the early PET 2001, rather than specifications for every computer later sold under the PET or CBM name. (Braun’s contemporary review.)
Characters as building blocks
The 6502 drove a display of 40 columns by 25 rows. A character occupied each position. Alongside letters and numbers were lines, blocks, curves and playing-card symbols, with reversed forms that exchanged light and dark. These shapes made diagrams, borders and games possible without a separately addressed bitmap screen. The PETSCII chart explains the character family that continued into later Commodore computers.
BYTE’s October 1977 report identified the BASIC as Microsoft’s. It described strings, arrays and PEEK and POKE, which let a program read and change memory. The language supplied calculations and text handling; the machine’s screen editor helped with the practical job of changing a numbered program line. Commodore’s October 1978 manual treats keyboard input and screen editing before taking the reader through BASIC, peripherals and machine language. (BYTE, October 1977, p.50; Commodore manual.)
Saving work and reaching outside
The cassette recorder gave programs a life beyond the next switch-off. SAVE wrote a named program, LOAD brought it back, and VERIFY checked a recording against memory. The manual also describes IEEE-488 communication and a user port: the self-contained cabinet still had routes to printers, storage and other equipment.
There were physical compromises. Braun found the closely spaced, calculator-like keyboard awkward to type on, and the 40-character line restrictive. His account praised the integrated machine while showing what an owner had to work around. Later PET/CBM models changed the keyboard, memory and display arrangements; they should not be treated as interchangeable with this first version.
A continuing Commodore vocabulary
The PET connects Commodore’s acquisition of MOS Technology to the BASIC computers that followed. The VIC-20 and Commodore 64 changed the display and sound possibilities substantially, but retained a recognisable BASIC and screen-editing environment. VICE preserves PET models as well as those later machines, with the differences between models still relevant when choosing software.
Sources
- Ludwig Braun, “Commodore PET”, Creative Computing, July–August 1978: contemporary operation, prices, display, cassette commands and keyboard criticism. Public transcription.
- Commodore, PET 2001-8 Personal Computer User Manual, first edition, October 1978, chapters 2–8: editor, BASIC, interfaces and machine language. Original manual scan.
- “Commodore’s New PET Computer”, BYTE, October 1977, p.50: Microsoft BASIC, integrated equipment and announced prices. Original issue.
- Powerhouse Collection, object 99/127/1-2, PET Users Manual: museum catalogue corroborating the manual’s identity and 1978 date (web, secondary description). https://collection.powerhouse.com.au/object/166565