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SCELBAL
SCELBAL, short for SCientific ELementary BAsic Language, is a version of the BASIC programming language released in 1976 for the SCELBI and other early Intel 8008 and 8080-based microcomputers like the Mark-8. Later add-ons to the language included an extended math package and string handling. The original version required 8 kB of RAM, while the additions demanded at least 12 kB.
The language was published in book form, with introductory sections followed by flowcharts and then the 8008 assembler code. The book described ways to save more memory, turning off arrays for instance, and how the user could add their own new features to the language.
The primary author of SCELBAL is Mark Arnold, who was a high-school student in 1974 when the SCELBI was announced. Arnold was friends with professors at the University of Wyoming (UW), and through them had arranged to have an account on their Sigma 7 mainframe computer. The first version of what became SCELBAL was written for this machine. Later that year, he wrote an 8008 cross compiler on that platform.
Arnold entered UW in 1975 and contacted Nat Wadsworth, one of the founders of SCELBI, pitching the idea of a compiled version of BASIC for their new platform. This would be a multi-pass system that would save the intermediate versions on cassette tape. This would be very tedious to use but would produce programs that would run on the 4 kB 8H models of the system. Wadsworth favored an interpreter, which would require 8 kB, which would be available on the new 8B models of the system. The language used floating point routines published by Wadsworth in 1975 in Machine Language Programming for the 8008.
It took Wadsworth several months to finally arrange a contract, which included sending Arnold an 8B development system. This significantly delayed the release of the language into 1976. Arnold speculated that, lacking these delays, SCELBAL could have been released at about the same time as Altair BASIC in late 1975. It was first presented in a lengthy article in the second issue of Dr. Dobb's Journal in February 1976.
The release of SCLEBAL was announced in an advertisement in Byte's June 1976 issue. The ad did not specifically link the language to the SCELBI platform, instead, it simply offered itself in book form as a complete source listing to create a version of BASIC on any 8008 or 8080 system with the requisite 8 kB of RAM. The book's price was $49, about $271 in 2024.
SCELBAL used a 32-bit (four byte) floating point format for numeric calculations, with a 23-bit mantissa, 1-bit sign for the mantissa, a 7-bit exponent, and 1-bit sign for the exponent. These were organized in reverse order, with the least significant byte of the mantissa in the first byte, followed by the middle and then most significant byte with the sign in the high bit. The exponent came last, again with the sign in the high bit. The manual provides well-documented assembly code for the entire math package, including entry points and usage notes. 32-bit formats were common in this era, while later versions of BASIC, starting with Microsoft BASIC for the MOS 6502, generally adopted a 40-bit (five byte) format for added precision.
SCELBAL was otherwise similar to other BASIC dialects, including early MS versions like Altair BASIC, lacking string variables and operators and a number of mathematic functions. Other differences were less pronounced. The IF statement had an optional form IF...GOTO that removed the need for THEN, IF X<Y GOTO 100. It also retained the MS-style short form for the same concept, IF X<Y THEN 100. It also allowed conditional execution of other statements, such as IF X<Y THEN PRINT X.
Hub AI
SCELBAL AI simulator
(@SCELBAL_simulator)
SCELBAL
SCELBAL, short for SCientific ELementary BAsic Language, is a version of the BASIC programming language released in 1976 for the SCELBI and other early Intel 8008 and 8080-based microcomputers like the Mark-8. Later add-ons to the language included an extended math package and string handling. The original version required 8 kB of RAM, while the additions demanded at least 12 kB.
The language was published in book form, with introductory sections followed by flowcharts and then the 8008 assembler code. The book described ways to save more memory, turning off arrays for instance, and how the user could add their own new features to the language.
The primary author of SCELBAL is Mark Arnold, who was a high-school student in 1974 when the SCELBI was announced. Arnold was friends with professors at the University of Wyoming (UW), and through them had arranged to have an account on their Sigma 7 mainframe computer. The first version of what became SCELBAL was written for this machine. Later that year, he wrote an 8008 cross compiler on that platform.
Arnold entered UW in 1975 and contacted Nat Wadsworth, one of the founders of SCELBI, pitching the idea of a compiled version of BASIC for their new platform. This would be a multi-pass system that would save the intermediate versions on cassette tape. This would be very tedious to use but would produce programs that would run on the 4 kB 8H models of the system. Wadsworth favored an interpreter, which would require 8 kB, which would be available on the new 8B models of the system. The language used floating point routines published by Wadsworth in 1975 in Machine Language Programming for the 8008.
It took Wadsworth several months to finally arrange a contract, which included sending Arnold an 8B development system. This significantly delayed the release of the language into 1976. Arnold speculated that, lacking these delays, SCELBAL could have been released at about the same time as Altair BASIC in late 1975. It was first presented in a lengthy article in the second issue of Dr. Dobb's Journal in February 1976.
The release of SCLEBAL was announced in an advertisement in Byte's June 1976 issue. The ad did not specifically link the language to the SCELBI platform, instead, it simply offered itself in book form as a complete source listing to create a version of BASIC on any 8008 or 8080 system with the requisite 8 kB of RAM. The book's price was $49, about $271 in 2024.
SCELBAL used a 32-bit (four byte) floating point format for numeric calculations, with a 23-bit mantissa, 1-bit sign for the mantissa, a 7-bit exponent, and 1-bit sign for the exponent. These were organized in reverse order, with the least significant byte of the mantissa in the first byte, followed by the middle and then most significant byte with the sign in the high bit. The exponent came last, again with the sign in the high bit. The manual provides well-documented assembly code for the entire math package, including entry points and usage notes. 32-bit formats were common in this era, while later versions of BASIC, starting with Microsoft BASIC for the MOS 6502, generally adopted a 40-bit (five byte) format for added precision.
SCELBAL was otherwise similar to other BASIC dialects, including early MS versions like Altair BASIC, lacking string variables and operators and a number of mathematic functions. Other differences were less pronounced. The IF statement had an optional form IF...GOTO that removed the need for THEN, IF X<Y GOTO 100. It also retained the MS-style short form for the same concept, IF X<Y THEN 100. It also allowed conditional execution of other statements, such as IF X<Y THEN PRINT X.