The Sinclair ZX Spectrum is an 8-bit personal home computer released in the United Kingdom in 1982 by Sinclair Research Ltd. Referred to during development as the ZX81 Colour and ZX82, the machine was launched as the ZX Spectrum by Sinclair to highlight the machine's colour display, compared with the black-and-white of its predecessor, the Sinclair ZX81.
The Spectrum was among the first mainstream audience home computers in the UK, similar in significance to the Commodore 64 in the USA; the C64 was a major rival to the Spectrum in the UK market during the early 1980s (The BBC Microcomputer was another major competitor). The introduction of the ZX Spectrum led to a boom of companies producing software and hardware for it. The effects of this are still seen.
The Spectrum is based on a Zilog Z80 CPU running at 3.5 MHz (or NEC D780C-1 clone), the original model Spectrum has 16 KB (16×1024 byte) of ROM and either 16 KB or 48 KB of RAM. The hardware design is by Richard Altwasser of...
full article at wikipedia