A rainbow may refer to any of the following:
1. The Rainbow 100 was a microcomputer system originally released in 1982. It was developed by DEC (Digital Equipment Corporation) that used display circuitry from a VT102 computer (also developed by DEC), and a dual processor architecture. It featured both 4 MHz Zilog Z80 and 4.81 MHz Intel 8088 CPUs. The Rainbow 100 could be used in three different modes: VT102 mode, 8-bit CP/M mode (with use of the Z80 processor), or 16-bit CP/M-86 or MS-DOS mode (with use of the 8088 processor). It was available in three models: 110A, 100B, and 100+.
2. The Rainbow series is a 6-foot tall stack of books containing computer security standards. It was originally published by the U.S. Department of Defense in the early 1980s and again by the National Computer Security Center through the early 1990s.