Commodore  CBM 730 or BX256

Commodore CBM 730 (B256-80 + CoProcessor)

The Commodore CBM 730 has 256KByte RAM, just like the CBM 720 and provides an extra curcuit board that allowed for an Intel 8088 co-processor, very little software, if any, exists that takes advantage of this co-processor.

The main difference with the CBM 630 is the new graphics ROM that provides 8x14 pixel based letters as opposed to the 8x8 pixel based characters in the 630. The 730 also has a detachable keyboard, allowing for a more ergonomic set-up.

CBM 630/730 Coprocessor Board

The optional co-processor board for the CBM 630/730 with the Intel 8088 processor, giving the 630/730 the ability ro run CP/M-86 1.1 or MS-DOS 1.25. This board did not give IBM PC Compatibility.

Commodore CBM 700 Series

The Commodore 700 series was introduced in 1982 and sold under a few different names. In the US they were sold as the B256 and PET 700 series, in Europe as the CBM 700 series, or CBM 256-80 / B256-80.

The hardware is identical to the CBM 600 series. The machines had an integrated monitor, detachable keyboard and two 5.25" disk drives. The BX256 model was capable of supporting an optional 8088 chip. Graphics and sound capabilities were also identical to the CBM series, except that the 700s had a new character generator ROM, and graphics were generated off an 8x14 matrix. The Kernal ROM determined which generator to use based on inputs that were hard-soldered on the main board.

MOS 6509 CPU

THe MOS Technology 6509 is an enhanced version of the 8-bit 6502 CPU. Using bank switching the 6509 is able to address up to 1MByte of RAM. The 6502 also could do bank-switching, but did so via separate logic circuits, the 6509 had this logic built in. This extra logic made the 6509 difficult to program, and it was mainly used in the Commodore CBM-II line of computers.

Source:WikiPedia - MOS Technology 6509
Source:WikiPedia - MOS Technology 6502

SID (MOS 6581) - Sound Interface Device

SID is short for Sound Interface Device. It is the name of the sound chip that was used in the VC10, the commodore 64 and the Commodore 128. SID was developed by Bob Yannes, an employee of MOS Technology. Bob was not only an engineer but also knew a lot about music. His intention was to create a different sound chip than other devices at the time. He implemented a subtractive synthesis chip. The chip's distinctive sound is easily recognized and was clearly ahead of the ocmpitition. The SID combines analog and digital circuitry that cannot be 100% emulated, even today.

Source: C64 Wiki
Released 1983 Country United States Brand Type COMMO CBM-II 700 Series Name CBM 730 or BX256 CPU Class 6502 CPU MOS 6509 @2MHz, Optional Z80 or Intel 8088 Memory 256kB RAM Sound Chip SID (MOS 6581) Sound 3 Voices, 9 octaves Display Chip MOS 6545 CRTC (80 column) Display 80x25 Monochrome text Sprites none System OS BASIC V4.0
Related Systems
Commodore PET/CBM - 2001/3000 Series
Commodore CBM 4000 Series
Commodore CBM 8000 Series
Commodore CBM-II 500 Series
Commodore CBM-II 600 Series
Commodore CBM-II 700 Series
CBM  730 or BX256 (1983)
Commodore C16
Commodore Vic/C64
Commodore Amiga
Commodore Amiga Desktops
Books & Publications
6502 CPU
Collection of books on the 6502 and compatible CPUs
Commodore 8-bit
Collection of books for the Commodore computer platform
Magazines & Serials
German Commodore 64/128 Magazine and themed Specials (Sonderheft)
Commodore Magazine
Magazine for the Commodore 64/128/Amiga
Commodore Revue
Commodore Revue is a French Magazine dedicated to Commodore and later to the Commodore Amiga in particular. The name later changed to Amiga Revue.
Commodore World
BiMonthly magazine for Commodore users in the USA
Commodure User
Oldest British Comodore Magazine
Compute's Gazette
Compute!'s Gazette was a computer magazine of the 1980s, directed at users of Commodore's 8-bit home computers.
Computer Club
Una rivista italiana di informatica dedicata a tutti i computer Commodore. An Italian computer information magazine dedicated to the Commodore Computer.
RUN focused on 1980's Commodore 8bit hardware like the Commodore 64, VIC-20, Plus/4, C16,116, 264, and 128.
Your Commodore
Your Commodore was a magazine for the Commodore range of computers, including the Commodore 64, Amiga, and Commodore PC range.
World Wide Web Links
WikiPedia: MOS Technology 6581
Wikipage about the 6581