Commodore CBM-II
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The Commodore CBM-II series was a short-lived series of personal computers from Commodore International, intended as a follow-on to the Commodore PET series, released in 1982.
Technical description
In the United States, the CBM-II had two incarnations, the P series and the B series. Similar machines were released in Europe, but the model numbers were sometimes different. The P series was intended for home use, while the B series was intended for business use. Both used a MOS Technology 6509 CPU, an enhanced version of the venerable 6502 that was capable of addressing up to 1 megabyte of RAM via bank switching, and the same MOS Technology SID sound chip that was used in the popular Commodore 64. The P series also used the MOS Technology VIC-II video chip from the C64. The B series used a MOS Technology 6845 video chip in place of the VIC-II to give an 80-column monochrome output more suitable for word processing and other business use than the VIC-II's 40-column display. An optional Intel 8088-based coprocessor board allowed the CBM series to run CP/M-86 and MS-DOS 1.25; however, the computers were not IBM PC Compatible and very little, if any, software taking advantage of this capability ever appeared.
Like the PET series, the CBM-II featured an IEEE-488 parallel bus for use by disk drives and printers and was completely compatible with the drives and printers for the PET line. Additionally, the CBM-II had an industry-standard RS-232 interface.
History
Due to the popularity of the C64, the P series was cancelled in the United States before it could be officially released; however, a few dealers who received preproduction units sold them. As these computers had not received approval from the Federal Communications Commission, this caused legal problems for Commodore. The units were recalled and destroyed, but a very small number exist today, in private collections. At least one model, the P500, was commercially released in Europe but only sold in small numbers.
The most common of the B series was the B128, which had 128 kilobytes of RAM. The B128 did not sell well, and ultimately Commodore's inventory was liquidated by Protecto Enterprises, a large Commodore mail order dealer based in Chicago, Illinois. The Protecto ads for the B128 bundle, including a dual disk drive, monitor and printer, appeared in various computer magazines for several years.
After discontinuing the CBM-II series, Commodore handed its documentation, schematics, and all other information over to the Chicago B128 Users Group, who developed a library of software for the series. Its library, however, paled in comparison to the large software libraries enjoyed by the C64 and Commodore VIC-20.
The design of the CBM-II series was revised, made compatible with the C64, and ultimately became the much more successful Commodore 128.
CBM-II trivia
- A B128 made a brief appearance as a prop in the 1985 movie The Jewel of the Nile, starring Michael Douglas and Kathleen Turner.
| List of Commodore microcomputers |
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MOS Technology 6502-based (8-bit): MOS/CBM KIM-1 |
PET/CBM |
CBM-II (aka B/P series) |
VIC-20/VC-20 |
C64 |
SX-64 |
C16 & 116 |
Plus/4 |
C128 |