Personal computing took another step forward last week with Hewlett-Packard's launch of the Integral, a luggable micro that runs Unix.

Unix or one of its clones is usually regarding as the Operating System of the future, a multi-tasking environment that will take over from MSDOS as the standard in microcomputing. So far it has been living up to its billing it dribs and drabs, but the appearance of the Integral could give it a shot in the arm.

Hewlett-Packard's machine weighs in at 25lbs. Besides Unix System III implemented under the name of HP UX, it offers 512K of RAM, 32K more to drive the 9" amber electroluminescent screen, 256K of ROM to accommodate the operating system, a built-in 710K floppy, and the H-P Thinkjet printer - an impressive package for the price of £5,450.

H-P says it expects the machine to sell mainly to scientific and engineering users (the company's traditional market), but it has also put windows and its Personal Applications Manager into the bundle.

Version 7 Unix, at the core of System III, was developed in 1977, but wasn't distributed until 1979. Estimates of the number of working Unix or Unix-like systems in the UK last year vary from 4,500 to 12,000 - a minute total when you consider that there are now more than 200 hardware vendors offering Unix or its more common derivative, Xenix (75-80 per cent of Unix licences around the world are, in fact, for Xenix, Microsoft's version that recently won the support of IBM in its PC AT).

Business software publishers are making sure that when Unix takes off they'll be in a position to supply the applications. Redwood, for example, claims to have the first integrated packages developed in Europe for Unix systems.

But the turning point will probably come when users move in large numbers from standalone single user personal computers to communicating, multi-tasking systems.