Comment by bitwize

Microsoft itself popularized BASIC on microcomputers with its 8080 BASIC, starting on the Altair and ported to everything with A, B, C, D, E, H, and L registers since.

Before then, however, BASIC was already popular on minicomputers as both an introductory language for beginners and a business language; the various "Business BASIC" dialects providing a small-business alternative to COBOL on mainframes with their features for decimal math and ISAM database access.