altair
The famous first product of a certain Micro-Soft, for the allegedly first personal computer in the market, would set the basis of what would soon become a de facto standard for the BASIC language.
There were actually three MS-BASICs for the Altair computer.
The original version released in July 1975 was made for the 4KB version of the Altair and implemented only 30 keywords. It had only 4 mathematical functions, only one floating-point data type, and no support for string variables nor string manipulation. Most of its keywords were maintained as original in the later/bigger versions, so the humble 4K is the version referred to by this page.
The following version was made for Altairs with dazzling 8KB of RAM. It supported string variables and implemented 61 keywords, among them all of the 4K version, trigonometric functions other than SIN, RND, PEEK, POKE and the family of string manipulation functions such as MID$ and LEFT$, imported from DEC's BASIC-PLUS, which Bill Gates was acquainted to from his high-school days. This version was adopted as the Microsoft BASIC-80 codebase which would soon rule the first generation of BASICs for microcomputers.
The last "Extended" version, released in July 1978 for 12KB Altairs, was already very similar to the BASIC most of us became friends with. 21 keywords were added or improved, such as ELSE for the IF…THEN decision structures, and PRINT USING. It also implemented human-readable error messages, three different numerical types and their suffixes for variable names: % for 16-bit integers, ! for the default 32-bit floating point numbers and # for 64-bit, double-precision floating point values.
TO DO: a list or prose text about this BASIC's features, bugs, Easter eggs, tricks, singularities
TO DO: notes about the REPL or IDE used, keyboard shortcuts and commands, command-line options for compiling and linking, environment variables which might be set…
The young Bill Gates was not happy with the quick and widespread piracy of their BASIC among the computer enthusiasts, and wrote his famous "An Open Letter to Hobbysts" in February 1976 equalling the "free distribution" of Altair BASIC to stealing. One of the many reactions from the community was the conception of TinyBASIC and its many implementations (some of them pretty current and in use).