Because it was one of the first truly low-cost computers, the Sinclair ZX80 was many people’s first introduction to personal computing. While its diminutive size—about 6.9” x 8.5” x 1.4” and weighing a little over half a pound—is impressive even today, its similarly diminutive RAM (1K), inability to output video when the processor was busy, and one-piece, completely flat membrane keyboard weren’t even positives then.
Interestingly, instead of being able to type directly once the computer was on, the keyboard defaulted to entering the BASIC keyword printed above a particular key instead. While this became an advantage as its users became more experienced programmers and was a feature carried over to future Sinclair computers, it was a decidedly non-intuitive mode of operation for everyone else.