S-BASIC (for Structured Basic) was a "structured"

BASIC Basic or BASIC may refer to: Science and technology * BASIC, a computer programming language * Basic (chemistry), having the properties of a base * Basic access authentication, in HTTP Entertainment * Basic (film), ''Basic'' (film), a 2003 film ...

variant, distributed with

Kaypro Kaypro Corporation was an American home and personal computer manufacturer based in Solana Beach, California, in the 1980s. The company was founded by Non-Linear Systems (NLS) to compete with the popular Osborne 1 portable microcomputer. Kaypro ...

CP/M CP/M, originally standing for Control Program/Monitor and later Control Program for Microcomputers, is a mass-market operating system created in 1974 for Intel 8080/Intel 8085, 85-based microcomputers by Gary Kildall of Digital Research, Dig ...

systems. It was made by Topaz Programming is distributed by Micro-Ap (San Ramon, California). SBasic was compatible with the syntax of BASIC, a

programming language A programming language is a system of notation for writing computer programs. Programming languages are described in terms of their Syntax (programming languages), syntax (form) and semantics (computer science), semantics (meaning), usually def ...

commonly used in the 1970s through the 1980s, as well as Fortran77. However, the language relaxed many of the requirements of BASIC and had more flexibility than Fortran. For instance, line numbers were optional, and permitted non-numeric characters. In addition, SBasic offered developers

structured programming Structured programming is a programming paradigm aimed at improving the clarity, quality, and development time of a computer program by making specific disciplined use of the structured control flow constructs of selection ( if/then/else) and repet ...

concepts, including

recursion Recursion occurs when the definition of a concept or process depends on a simpler or previous version of itself. Recursion is used in a variety of disciplines ranging from linguistics to logic. The most common application of recursion is in m ...

and nesting. Many

PL/I PL/I (Programming Language One, pronounced and sometimes written PL/1) is a procedural, imperative computer programming language initially developed by IBM. It is designed for scientific, engineering, business and system programming. It has b ...

programs could be compiled with little modification, though SBasic did not offer an extensive

function library Function or functionality may refer to: Computing * Function key, a type of key on computer keyboards * Function model, a structured representation of processes in a system * Function object or functor or functionoid, a concept of object-orien ...

. Among the more advanced features was the ability to "base" a variable or

array An array is a systematic arrangement of similar objects, usually in rows and columns. Things called an array include: {{TOC right Music * In twelve-tone and serial composition, the presentation of simultaneous twelve-tone sets such that the ...

, making the memory location dynamic and modifiable during execution. SBasic programs had the ability to access memory areas reserved for the

operating system An operating system (OS) is system software that manages computer hardware and software resources, and provides common daemon (computing), services for computer programs. Time-sharing operating systems scheduler (computing), schedule tasks for ...

unless prohibited from doing so by the operating system itself. (Kaypro's CP/M had no such prohibitions.) This enabled direct utilization and modification of DMA and other memory areas. This feature also permitted a program to modify itself at run-time. This capability also allowed modifying the

instruction pointer The program counter (PC), commonly called the instruction pointer (IP) in Intel x86 and Itanium microprocessors, and sometimes called the instruction address register (IAR), the instruction counter, or just part of the instruction sequencer, is ...

, so a program could effectively link other executable modules that were read during execution as data. Unlike

BASIC interpreter A BASIC interpreter is an Interpreter (computing), interpreter that enables users to enter and run programs in the BASIC programming language, language and was, for the first part of the microcomputer era, the default Application software, applica ...

s that stored "

p-code Bytecode (also called portable code or p-code) is a form of instruction set designed for efficient execution by a software interpreter. Unlike human-readable source code, bytecodes are compact numeric codes, constants, and references (normal ...

" that was parsed by an execution module, SBasic was a two-pass

compiler In computing, a compiler is a computer program that Translator (computing), translates computer code written in one programming language (the ''source'' language) into another language (the ''target'' language). The name "compiler" is primaril ...

, ultimately producing .com files that were executable. The language was written in a subset of itself and compiled using a .com kernel, then stored on diskette (or hard drive on the last KayPro model). The source was distributed with some KayPro models. This encouraged

open-source Open source is source code that is made freely available for possible modification and redistribution. Products include permission to use and view the source code, design documents, or content of the product. The open source model is a decentrali ...

-like modification of the language, with some early pre-Internet user groups exchanging physical diskettes by regular mail. Not to be confused with the namesake SBasic (S for Spectral Basic) Programming Language for the commercial Spectral UV-Visible software.

Reception

Jerry Pournelle Jerry Eugene Pournelle (; August 7, 1933 – September 8, 2017) was an American scientist in the area of operations research and ergonomics, human factors research, a science fiction writer, essayist, journalist, and one of the first bloggers. ...

in 1983 wrote that S-BASIC "is quite nice", stating that it "rivals CB-80". He presumed that Kaypro users would "will begin by using Microsoft

MBASIC MBASIC is the Microsoft BASIC, Microsoft BASIC implementation of BASIC for the CP/M operating system. MBASIC is a descendant of the original Altair BASIC interpreters that were among Microsoft's first products. MBASIC was one of the two versions o ...

, then start translating their programs into S-BASIC and learn more about structured programming". Pournelle added, "If I had to give an award for the most unreadable computer document I've ever seen, the original S-BASIC manual would win hands down"; however, Kaypro had rewritten it and "is a great deal more sensible".

References

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BASIC compilers Sbasic Discontinued BASICs BASIC programming language family {{compu-lang-stub