ROM BASIC programming language

In the early days of personal computers, circa 1980, providing the customer with a method of programming their own computer was a standard feature. The most popular consumer programming language at that time was BASIC, so most home computers included a ROM based BASIC interpreter.

All major consumer variants were quite similar in how they handled general programming concepts like variables, subroutines, string manipulation, and so forth. The variants diverged greatly in how they handled "machine specific" concepts such as graphics, sound, and mass storage.

Some major BASIC variants from this era include:

Apple II family - Integer BASIC[?] and Applesoft BASIC
Atari 8-bit family - Atari BASIC
Commodore 64 - C64 BASIC[?]
IBM PC - PC BASIC[?]
Tandy TRS-80 - Level I BASIC[?] and Level II BASIC[?]

Many of the interpreters for these BASIC variants were written in whole or in part by Microsoft.