BASIC (an acronym for Beginner's All-purpose Symbolic Instruction Code) is a family of general-purpose, high-level programming languages whose design philosophy emphasizes ease of use.
Versions of BASIC became widespread on microcomputers in the mid-1970s and 1980s. Microcomputers usually shipped with BASIC, often in the machine's firmware. Having an easy-to-learn language on these early personal computers allowed small business owners, professionals, hobbyists, and consultants to develop custom software on computers they could afford.
BASIC remains popular in many dialects and in new languages influenced by BASIC, such as Microsoft's Visual Basic. In 2006, 59% of developers for the .NET Framework used Visual Basic .NET as their only programming language.
History
Before the mid-1960s, the only computers were mainframes. Users submitted jobs on punched cards or similar media to computer operators. The computer stored these, then used a batch processing system to run this queue of jobs one after another - allowing very high levels of utilization of these expensive machines. As the performance of computing hardware rose through the 1960s, multi-processing was developed. This allowed a mix of batch jobs to be run together, but the real revolution was the development of time-sharing.
Time-sharing allowed multiple remote interactive users to share use of the computer, interacting with the computer from terminals with keyboards and teletype printers, and later display screens, in much the same way as desktop computers or personal computers would be used later.
Origin
The original BASIC language was designed on May 1, 1964 by John Kemeny and Thomas Kurtz and implemented by a team of Dartmouth College students under their direction. The acronym BASIC comes from the name of an unpublished paper by Thomas Kurtz. BASIC was designed to allow students to write mainframe computer programs for the Dartmouth Time-Sharing System. It was intended specifically for less technical users who did not have or want the mathematical background previously expected. Being able to use a computer to support teaching and research was quite novel at the time.
The language was based on FORTRAN II, with some influences from ALGOL 60 and with additions to make it suitable for timesharing. Initially, BASIC concentrated on supporting straightforward mathematical work, with matrix arithmetic support from its initial implementation as a batch language, and character string functionality being added by 1965.
The designers of the language decided to make the compiler available free of charge so that the language would become widespread. (In the 1960s, software became a chargeable commodity; until then, it was provided without charge as a service with the very expensive computers, usually available only to lease.) They also made it available to high schools in the Hanover area, and put a considerable amount of effort into promoting the language. In the following years, as other dialects of BASIC appeared, Kemeny and Kurtz's original BASIC dialect became known as Dartmouth BASIC.
Spread on minicomputers
Knowledge of the relatively simple BASIC became widespread for a computer language, and it was implemented by a number of manufacturers, becoming fairly popular on newer minicomputers such as the DEC PDP series and the Data General Nova. The BASIC language was also central to the HP Time-Shared BASIC system in the late 1960s and early 1970s, where the language was implemented as an interpreter. A version was a core part of the Pick operating system from 1973 onward, where a compiler renders it into bytecode, able to be interpreted by a virtual machine.
During this period a number of simple computer games were written in BASIC, most notably Mike Mayfield's Star Trek. A number of these were collected by DEC employee David H. Ahl and published in a newsletter he compiled. He later collected a number of these into book form, 101 BASIC Computer Games, published in 1973. During the same period, Ahl was involved in the creation of a small computer for education use, an early personal computer. When management refused to support the concept, Ahl left DEC in 1974 to found the seminal computer magazine, Creative Computing. The book remained popular, and was re-published on several occasions.
Explosive growth: the home computer era
The introduction of the first microcomputers in the mid-1970s was the start of explosive growth for BASIC. It had the advantage that it was fairly well known to the young designers and computer hobbyists who took an interest in microcomputers. Despite Dijkstra's famous judgement in 1975, "It is practically impossible to teach good programming to students that have had a prior exposure to BASIC: as potential programmers they are mentally mutilated beyond hope of regeneration", BASIC was one of the few languages that was both high-level enough to be usable by those without training and small enough to fit into the microcomputers of the day, making it the de facto standard programming language on early microcomputers.
One of the first BASICs to appear was Tiny BASIC, a simple BASIC variant designed by Dennis Allison at the urging of Bob Albrecht of the Homebrew Computer Club. He had seen BASIC on minicomputers and felt it would be the perfect match for new machines like the MITS Altair 8800. How to design and implement a stripped-down version of an interpreter for the BASIC language was covered in articles by Allison in the first three quarterly issues of the People's Computer Company newsletter published in 1975 and implementations with source code published in Dr. Dobb's Journal of Tiny BASIC Calisthenics & Orthodontia: Running Light Without Overbyte. Versions were written by Li-Chen Wang and Tom Pittman.
In 1975 MITS released Altair BASIC, developed by Bill Gates and Paul Allen as the company Micro-Soft, which eventually grew into corporate giant Microsoft. The first Altair version was co-written by Gates, Allen, and Monte Davidoff.
Almost universally, home computers of the 1980s had a ROM-resident BASIC interpreter, which the machines booted directly into. When the Apple II, PET 2001, and TRS-80 were all released in 1977, all three had BASIC as their primary programming language and operating environment. Upon boot, a BASIC interpreter in immediate mode was presented, not the command line interface used on systems running CP/M or MS-DOS. Commodore Business Machines included a version of Microsoft BASIC. The Apple II and TRS-80 each had two versions of BASIC, a smaller introductory version introduced with the initial releases of the machines and a more advanced version developed as interest in the platforms increased. As new companies entered the field, additional versions were added that subtly changed the BASIC family. The Atari 8-bit family had its own Atari BASIC that was modified in order to fit on an 8 kB ROM cartridge. The BBC published BBC BASIC, developed by Acorn Computers Ltd, incorporating many extra structured programming keywords and advanced floating-point operation features.
As the popularity of BASIC grew in this period, magazines published complete source code in BASIC for games, utilities, and other programs. Given BASIC's straightforward nature, it was a simple matter to type in the code from the magazine and execute the program. Different magazines were published featuring programs for specific computers, though some BASIC programs were considered universal and could be used in machines running any variant of BASIC (sometimes with minor adaptations). Many books of type-in programs were also available, and in particular, Ahl published versions of the original 101 BASIC games converted into the Microsoft dialect and published it from Creative Computing as BASIC Computer Games. This book, and its sequels, provided hundreds of ready-to-go programs that could be easily converted to practically any BASIC-running platform. The book reached the stores in 1978, just as the home computer market was starting off, and it became the first million-selling computer book. Later packages, such as Learn to Program BASIC would also have gaming as an introductory focus.
On the business-focused CP/M computers which soon became widespread in small business environments, Microsoft BASIC (MBASIC) was one of the leading applications.
