Commodore CBM-II
Encyclopedia
The Commodore CBM-II series was a short-lived range of 8-bit
personal computer
s from Commodore Business Machines (CBM)
, intended as a follow-on to the Commodore PET
series, released in 1982.
PETs" for their unique styling.
The P series used the VIC-II
40-column color video chip like the C64. It also included two standard Atari
-style joystick ports. The 6509 CPU
ran at 1 MHz in the P series due to the use of the VIC-II chip.
The B series used a 6545 CRTC video chip to give an 80-column "green screen
" monochrome output more suitable for word processing and other business use than the VIC-II's 40-column display. Most models have the Motorola 68B45 installed which is a pin compatible variant rather than the MOS 6545A1 2 MHz part. On the B series the 6509 CPU ran at 2 MHz.
Features common to both the P and B series included an 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
(however, no CBM-II model came with more than 256 kilobyte
s of RAM, 1/4 megabyte
). The sound chip was the 6581 SID
, the same one that was used in the popular Commodore 64
(C64) but with some limitations as it was over-clocked to 2 MHz. Additionally, the CBM-II had an industry-standard RS-232
serial interface and an IEEE-488
parallel bus (for use by disk drives and printers) just like the PET/CBM series. The CBM-II's built-in operating system used an enhanced version of CBM BASIC
version 4.0.
An optional Intel 8088
-based coprocessor board allowed the CBM-II series to run CP/M-86
1.1 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. The coprocessor board only ran on hi-profile machines due to power supply and mechanical spacing requirements.
The production naming within the United States
and Canada
was the B128/B256 and CBM128-80/CBM 256-80 while in Europe
they were known as the 600 and 700 series respectively (no "B" in front of the model number). The P machine was known worldwide as the 500 series. There are prototype models though such as the B500 (earlier B128 design) and B700 (earlier CBM 128-80/CBM 256-80 design) known to exist.
, 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 low-profile B128 (called the CBM 610 in Europe), which had 128 kilobytes of RAM. The B128 did not sell well, and ultimately Commodore's inventory was liquidated by Protecto Enterprises ("We Love Our Customers"), 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. The terms of the liquidation deal did not allow Protecto to advertise the computer's manufacturer, so it was simply referred to as a "128k computer". The Commodore name plate was legible in the photo in several of the ads, however.
After discontinuing the CBM-II range, Commodore handed its documentation, schematics, and all other information over to CBUG, the Chicago B128 Users Group.
Among these materials was a prototype motherboard using an Intel 8088
processor, which hints at the possibility the line could have been made IBM compatible if production had continued.
CBUG went on to develop a library of software for the computers. Its library, however, paled in comparison to the large software libraries enjoyed by the C64 and Commodore VIC-20
.
The rounded case design of the high profile CBM-II series would later be used in redesigned versions of the original PET/CBM computers, (such as the CBM8296) that the CBM-II line was designed to replace.
8-bit
The first widely adopted 8-bit microprocessor was the Intel 8080, being used in many hobbyist computers of the late 1970s and early 1980s, often running the CP/M operating system. The Zilog Z80 and the Motorola 6800 were also used in similar computers...
personal computer
Personal computer
A personal computer is any general-purpose computer whose size, capabilities, and original sales price make it useful for individuals, and which is intended to be operated directly by an end-user with no intervening computer operator...
s from Commodore Business Machines (CBM)
Commodore International
Commodore is the commonly used name for Commodore Business Machines , the U.S.-based home computer manufacturer and electronics manufacturer headquartered in West Chester, Pennsylvania, which also housed Commodore's corporate parent company, Commodore International Limited...
, intended as a follow-on to the Commodore PET
Commodore PET
The Commodore PET was a home/personal computer produced from 1977 by Commodore International...
series, released in 1982.
Technical description
The CBM-II had two incarnations, the P series (P = personal, or, home use) and the B series (B = business use). The B series was available with a built-in monochrome monitor (hi-profile) with detached keyboard, and also as a single unit with built-in keyboard but no monitor (lo-profile). These machines were known as the "PorschePorsche
Porsche Automobil Holding SE, usually shortened to Porsche SE a Societas Europaea or European Public Company, is a German based holding company with investments in the automotive industry....
PETs" for their unique styling.
The P series used the VIC-II
MOS Technology VIC-II
The VIC-II , specifically known as the MOS Technology 6567/8562/8564 , 6569/8565/8566 , is the microchip tasked with generating Y/C/composite video graphics and DRAM refresh signals in the Commodore 64 and C128 home computers.Succeeding MOS's original VIC , the VIC-II was one of the two chips...
40-column color video chip like the C64. It also included two standard Atari
Atari
Atari is a corporate and brand name owned by several entities since its inception in 1972. It is currently owned by Atari Interactive, a wholly owned subsidiary of the French publisher Atari, SA . The original Atari, Inc. was founded in 1972 by Nolan Bushnell and Ted Dabney. It was a pioneer in...
-style joystick ports. The 6509 CPU
MOS Technology 6509
The MOS Technology 6509, an enhanced version of the popular 6502 microprocessor, was capable of addressing up to 1 megabyte of RAM via bank switching. While numerous 6502-based processors could do bank switching, they did this via separate logic...
ran at 1 MHz in the P series due to the use of the VIC-II chip.
The B series used a 6545 CRTC video chip to give an 80-column "green screen
Green Screen
The Green Screen international wildlife film festival is held annually in Eckernförde, Germany. The festival shows full-length and short nature documentaries about animals in their natural habitat. It is the only festival of its kind in Germany...
" monochrome output more suitable for word processing and other business use than the VIC-II's 40-column display. Most models have the Motorola 68B45 installed which is a pin compatible variant rather than the MOS 6545A1 2 MHz part. On the B series the 6509 CPU ran at 2 MHz.
Features common to both the P and B series included an MOS Technology 6509
MOS Technology 6509
The MOS Technology 6509, an enhanced version of the popular 6502 microprocessor, was capable of addressing up to 1 megabyte of RAM via bank switching. While numerous 6502-based processors could do bank switching, they did this via separate logic...
CPU, an enhanced version of the venerable 6502
MOS Technology 6502
The MOS Technology 6502 is an 8-bit microprocessor that was designed by Chuck Peddle and Bill Mensch for MOS Technology in 1975. When it was introduced, it was the least expensive full-featured microprocessor on the market by a considerable margin, costing less than one-sixth the price of...
, that was capable of addressing up to 1 megabyte
Megabyte
The megabyte is a multiple of the unit byte for digital information storage or transmission with two different values depending on context: bytes generally for computer memory; and one million bytes generally for computer storage. The IEEE Standards Board has decided that "Mega will mean 1 000...
of RAM via bank switching
Bank switching
Bank switching is a technique to increase the amount of usable memory beyond the amount directly addressable by the processor. It can be used to configure a system differently at different times; for example, a ROM required to start a system from diskette could be switched out when no longer...
(however, no CBM-II model came with more than 256 kilobyte
Kilobyte
The kilobyte is a multiple of the unit byte for digital information. Although the prefix kilo- means 1000, the term kilobyte and symbol KB have historically been used to refer to either 1024 bytes or 1000 bytes, dependent upon context, in the fields of computer science and information...
s of RAM, 1/4 megabyte
Megabyte
The megabyte is a multiple of the unit byte for digital information storage or transmission with two different values depending on context: bytes generally for computer memory; and one million bytes generally for computer storage. The IEEE Standards Board has decided that "Mega will mean 1 000...
). The sound chip was the 6581 SID
MOS Technology SID
The MOS Technology 6581/8580 SID is the built-in Programmable Sound Generator chip of Commodore's CBM-II, Commodore 64, Commodore 128 and Commodore MAX Machine home computers...
, the same one that was used in the popular Commodore 64
Commodore 64
The Commodore 64 is an 8-bit home computer introduced by Commodore International in January 1982.Volume production started in the spring of 1982, with machines being released on to the market in August at a price of US$595...
(C64) but with some limitations as it was over-clocked to 2 MHz. Additionally, the CBM-II had an industry-standard RS-232
RS-232
In telecommunications, RS-232 is the traditional name for a series of standards for serial binary single-ended data and control signals connecting between a DTE and a DCE . It is commonly used in computer serial ports...
serial interface and an IEEE-488
IEEE-488
IEEE-488 is a short-range digital communications bus specification. It was created for use with automated test equipment in the late 1960s, and is still in use for that purpose. IEEE-488 was created as HP-IB , and is commonly called GPIB...
parallel bus (for use by disk drives and printers) just like the PET/CBM series. The CBM-II's built-in operating system used an enhanced version of CBM BASIC
Commodore BASIC
Commodore BASIC, also known as PET BASIC, is the dialect of the BASIC programming language used in Commodore International's 8-bit home computer line, stretching from the PET of 1977 to the C128 of 1985...
version 4.0.
An optional Intel 8088
Intel 8088
The Intel 8088 microprocessor was a variant of the Intel 8086 and was introduced on July 1, 1979. It had an 8-bit external data bus instead of the 16-bit bus of the 8086. The 16-bit registers and the one megabyte address range were unchanged, however...
-based coprocessor board allowed the CBM-II series to run CP/M-86
CP/M-86
CP/M-86 was a version of the CP/M operating system that Digital Research made for the Intel 8086 and Intel 8088. The commands are those of CP/M-80. Executable files used the relocatable .CMD file format...
1.1 and MS-DOS
MS-DOS
MS-DOS is an operating system for x86-based personal computers. It was the most commonly used member of the DOS family of operating systems, and was the main operating system for IBM PC compatible personal computers during the 1980s to the mid 1990s, until it was gradually superseded by operating...
1.25; however, the computers were not IBM PC compatible
IBM PC compatible
IBM PC compatible computers are those generally similar to the original IBM PC, XT, and AT. Such computers used to be referred to as PC clones, or IBM clones since they almost exactly duplicated all the significant features of the PC architecture, facilitated by various manufacturers' ability to...
and very little, if any, software taking advantage of this capability ever appeared. The coprocessor board only ran on hi-profile machines due to power supply and mechanical spacing requirements.
The production naming within the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
and Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
was the B128/B256 and CBM128-80/CBM 256-80 while in Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
they were known as the 600 and 700 series respectively (no "B" in front of the model number). The P machine was known worldwide as the 500 series. There are prototype models though such as the B500 (earlier B128 design) and B700 (earlier CBM 128-80/CBM 256-80 design) known to exist.
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 CommissionFederal Communications Commission
The Federal Communications Commission is an independent agency of the United States government, created, Congressional statute , and with the majority of its commissioners appointed by the current President. The FCC works towards six goals in the areas of broadband, competition, the spectrum, the...
, 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 low-profile B128 (called the CBM 610 in Europe), which had 128 kilobytes of RAM. The B128 did not sell well, and ultimately Commodore's inventory was liquidated by Protecto Enterprises ("We Love Our Customers"), a large Commodore mail order
Mail order
Mail order is a term which describes the buying of goods or services by mail delivery. The buyer places an order for the desired products with the merchant through some remote method such as through a telephone call or web site. Then, the products are delivered to the customer...
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. The terms of the liquidation deal did not allow Protecto to advertise the computer's manufacturer, so it was simply referred to as a "128k computer". The Commodore name plate was legible in the photo in several of the ads, however.
After discontinuing the CBM-II range, Commodore handed its documentation, schematics, and all other information over to CBUG, the Chicago B128 Users Group.
Among these materials was a prototype motherboard using an Intel 8088
Intel 8088
The Intel 8088 microprocessor was a variant of the Intel 8086 and was introduced on July 1, 1979. It had an 8-bit external data bus instead of the 16-bit bus of the 8086. The 16-bit registers and the one megabyte address range were unchanged, however...
processor, which hints at the possibility the line could have been made IBM compatible if production had continued.
CBUG went on to develop a library of software for the computers. Its library, however, paled in comparison to the large software libraries enjoyed by the C64 and Commodore VIC-20
Commodore VIC-20
The VIC-20 is an 8-bit home computer which was sold by Commodore Business Machines. The VIC-20 was announced in 1980, roughly three years after Commodore's first personal computer, the PET...
.
The rounded case design of the high profile CBM-II series would later be used in redesigned versions of the original PET/CBM computers, (such as the CBM8296) that the CBM-II line was designed to replace.
CBM-II trivia
- A CBM-II hi-profile machine made a brief appearance as a prop in the 1985 movie The Jewel of the NileThe Jewel of the NileThe Jewel of the Nile is a 1985 romantic adventure film, and a sequel to the 1984 film Romancing the Stone, with Michael Douglas, Kathleen Turner, and Danny DeVito reprising their roles...
, starring Michael Douglas and Kathleen Turner.
External links
- The Commodore CBM-II page — By Steve Gray
- The Commodore B-series page — By Edward Shockley
- Under the Hood of the Commodore P500 — By Ullrich von Bassewitz
- The Commodore 500, 600 and 700 Computers — By David Viner
- Hires graphics-board — By Winfried Falkenhahn
- Michau's CBM-II page — By Michał Pleban
- 6502.org - The Commodore CBM-II Page