Released on this day in 1981 the ZX81, by Sinclair Research. It will go on to sell over 1.5 million units around the world.

Operating system: Sinclair BASIC
CPU: Z80 @ 3.25 MHz
Memory: 1 KB (64 KB max. 56 KB usable)
Storage: External cassette tape recorder at 250 bps
Display: Monochrome display on UHF television
Graphics: 24 lines × 32 characters or 64 × 48 pixels graphics mode
Dimensions: 167mmm deep, 40mm
Mass: 350 grams