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Atari BASIC
Atari BASIC is an interpreter for the BASIC programming language that shipped with Atari 8-bit computers. Unlike most American BASICs of the home computer era, Atari BASIC is not a derivative of Microsoft BASIC and differs in significant ways. It includes keywords for Atari-specific features and lacks support for string arrays.
The language was distributed as an 8 KB ROM cartridge for use with the 1979 Atari 400 and 800 computers. Starting with the 600XL and 800XL in 1983, BASIC is built into the system. There are three versions of the software: the original cartridge-based "A", the built-in "B" for the 600XL/800XL, and the final "C" version in late-model XLs and the XE series. They only differ in terms of stability, with revision "C" fixing the bugs of the previous two.
Despite the Atari 8-bit computers running at a higher speed than most of its contemporaries, several technical decisions placed Atari BASIC near the bottom in performance benchmarks.
The machines that would become the Atari 8-bit computers were originally developed as second-generation video game consoles intended to replace the Atari VCS. Ray Kassar, the new president of Atari, decided to challenge Apple Computer by building a home computer instead.
This meant the designs needed to include the BASIC programming language, the standard for home computers. In early 1978, Atari licensed the source code to the MOS 6502 version of Microsoft BASIC. It was offered in two versions: one using a 32-bit floating point format that is about 7800 bytes when assembled, and another using an extended 40-bit format that is close to 9 KB.
Even the 32-bit version barely fit into the 8 KB size of the machine's ROM cartridge format. Atari also felt that they needed to expand the language to support the hardware features of their computers, similar to what Apple had done with Applesoft BASIC. This increased the size of Atari's version to around 11 KB; Applesoft BASIC on the Apple II+ is 10,240 bytes long. After six months the code was pared down to almost fit in an 8 KB ROM, but Atari had a January 1979 deadline for the Consumer Electronics Show (CES) where the machines would be demonstrated. They decided to ask for help to get a version of BASIC ready in time for the show.
In September 1978, Shepardson Microsystems won the bid on completing BASIC. At the time they were finishing Cromemco 16K Structured BASIC for the Z80-based Cromemco S-100 bus machines. Developers Kathleen O'Brien and Paul Laughton used Data General Business Basic, an integer-only implementation, as the inspiration for their BASIC, given Laughton's experience with Data General on a time-sharing system.
Cromemco BASIC includes an extended floating point implementation using a 14-digit binary-coded decimal (BCD) format made possible using all 16 registers of the Zilog Z80 processor. As it converts all data to the internal format at edit time, small constants like "1" use ~8 bytes of memory, and this could be a particular issue when storing arrays of numbers. To address this, the language also supports a smaller 6-digit BCD format.
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Atari BASIC
Atari BASIC is an interpreter for the BASIC programming language that shipped with Atari 8-bit computers. Unlike most American BASICs of the home computer era, Atari BASIC is not a derivative of Microsoft BASIC and differs in significant ways. It includes keywords for Atari-specific features and lacks support for string arrays.
The language was distributed as an 8 KB ROM cartridge for use with the 1979 Atari 400 and 800 computers. Starting with the 600XL and 800XL in 1983, BASIC is built into the system. There are three versions of the software: the original cartridge-based "A", the built-in "B" for the 600XL/800XL, and the final "C" version in late-model XLs and the XE series. They only differ in terms of stability, with revision "C" fixing the bugs of the previous two.
Despite the Atari 8-bit computers running at a higher speed than most of its contemporaries, several technical decisions placed Atari BASIC near the bottom in performance benchmarks.
The machines that would become the Atari 8-bit computers were originally developed as second-generation video game consoles intended to replace the Atari VCS. Ray Kassar, the new president of Atari, decided to challenge Apple Computer by building a home computer instead.
This meant the designs needed to include the BASIC programming language, the standard for home computers. In early 1978, Atari licensed the source code to the MOS 6502 version of Microsoft BASIC. It was offered in two versions: one using a 32-bit floating point format that is about 7800 bytes when assembled, and another using an extended 40-bit format that is close to 9 KB.
Even the 32-bit version barely fit into the 8 KB size of the machine's ROM cartridge format. Atari also felt that they needed to expand the language to support the hardware features of their computers, similar to what Apple had done with Applesoft BASIC. This increased the size of Atari's version to around 11 KB; Applesoft BASIC on the Apple II+ is 10,240 bytes long. After six months the code was pared down to almost fit in an 8 KB ROM, but Atari had a January 1979 deadline for the Consumer Electronics Show (CES) where the machines would be demonstrated. They decided to ask for help to get a version of BASIC ready in time for the show.
In September 1978, Shepardson Microsystems won the bid on completing BASIC. At the time they were finishing Cromemco 16K Structured BASIC for the Z80-based Cromemco S-100 bus machines. Developers Kathleen O'Brien and Paul Laughton used Data General Business Basic, an integer-only implementation, as the inspiration for their BASIC, given Laughton's experience with Data General on a time-sharing system.
Cromemco BASIC includes an extended floating point implementation using a 14-digit binary-coded decimal (BCD) format made possible using all 16 registers of the Zilog Z80 processor. As it converts all data to the internal format at edit time, small constants like "1" use ~8 bytes of memory, and this could be a particular issue when storing arrays of numbers. To address this, the language also supports a smaller 6-digit BCD format.