BACK at the dawn of the personal-computer era, in the late 1970s, millions of future programmers around the world got their first taste of writing software by using an ingenious little computer that cost less than $100 (about $240 in today’s money).

For the vast majority of individuals who could not afford the $2,500 (more than $6,000 today) that IBM and others were about to start charging for their revolutionary PCs, the diminutive Sinclair ZX80 and its ZX81 successor were inspirations. If you didn’t mind soldering the motherboard together yourself, the laptop-sized computer could be had in kit form for around $70. Your correspondent built two, one of each model. For a while Clive Sinclair, the innovative genius behind the ZX80/81 and much else, was the patron saint of schoolboys of all ages everywhere.

Sir Clive’s current equivalent is Nicholas Negroponte, co-founder of the Media Laboratory at the Massachusetts Institute of Technology and the father of one of the worthiest causes in contemporary computing. In the sweep of its ambition, Mr Negroponte’s pet project, One Laptop Per Child (OLPC), is remarkably similar to the thinking behind the original ZX80—giving inquisitive but economically deprived children the chance to feel the exhilaration of computer-based learning.

This week sees the realisation of Mr Negroponte’s five-year dream.