For the price of a PC, workstations could offer more power and flexibility.
When Disney's latest film, Toy Story, opens on 22 March, cinemas will witness a milestone in animation. Cartoons are the product of painstaking drawing. Each minute of film consists of hundreds of "frames", each drawn and shot one by one.

Toy Story is true to this tradition, in all but one respect. Instead of drawing frames with pen and ink, they have been produced on computers, more than 100 of them. The result is exceptionally smooth, three-dimensional images, as the characters - Buzz Lightyear, a hi-tech space ranger figure, and Woody, a cowboy doll - vie for the affections of six-year-old Andy.

Toy Story is the quintessential buddy movie. It won't be giving too much away to say that Woody and Buzz set aside their differences and become friends when they are left behind by accident when little Andy moves house.

The computer-generated scenes, although stylised, do seem more real than a conventionally drawn animation. Toy Story - produced by Pixar, which is run by Apple's founder, Steve Jobs - is not the first time these techniques have been used in film-making. Jurassic Park, for example, relied heavily on computer effects. But Toy Story is the first full-length film created in this way.

The sheer quantity of technology needed to make such films is mind-boggling. Computers are normally seen as time-saving devices, but Toy Story took as long to animate as a "conventional" film: more than four years. It uses some of the most powerful computers around, from Sun and Silicon Graphics. Rendering (the process of converting the artist's outline drawings to textured three-dimensional images) used a "farm" of 117 Sun SparcStations. The combined computing power was that of 300 Cray I supercomputers; one Sun would have needed 43 years to complete the task.

This league of computers, known as workstations, has long been the preserve of the power-hungry, the specialist or the rich. Even now, when a PC can be bought for little more than pounds 500, a workstation can cost more than pounds 100,000. Workstations are also widely used in engineering, medical research and design. Specialists will pay a premium for their ability to handle graphics or complex analysis at speed.

Lower down the market, however, distinctions between the workstation and the humble PC are becoming less clear. Typically, a workstation would be configured with a large hard disk, big chunks of memory (Ram) and a powerful graphics system. PCs can offer all of these, albeit at a price.

Traditionally, workstations have run Unix, a powerful but less than friendly operating system. Now PCs can also run Unix in the form of the shareware Linux. Low-end workstations, as well as powerful PCs, may also now run Windows NT, a lesser-known sibling of Microsoft's Windows. It lacks the refined interface of Windows 95, but offers Unix-like facilities, such as the ability to run more than one program at once (multi-tasking). A growing range of software is available off the shelf for Windows NT, which Microsoft markets as "NT Workstation".

The other distinctive feature of the workstation is the processor. It uses reduced instruction set computing (Risc) chips, which achieve far higher speeds than ordinary chips such as the Intel 486 or Pentium. But Risc chips have spread down market too. First to Acorn, then to Apple, and now to the PC. Some vendors are claiming that their Intel machines running NT are workstations or "workstation-class". To an extent, this claim is justified by the Pentium Pro, Intel's latest chip, which has Risc features.

Basic workstations running Unix or NT, cost from about pounds 3,500; pounds 5,000 should give a good level of performance including two-dimensional graphics. At this price, workstations compare well with top-end PCs. They come with advanced networking, graphics and communications built-in, and offer facilities such as video conferencing without needing extra cards. Silicon Graphics bundles a screen-top camera and pounds 4000 of software with its latest machines, for example.

Cheaper PC clones with a nominally high specification look a better deal than workstations. Yet there is little difference in price between the leading, quality PC vendors, such as IBM, Compaq or Apple, and workstations, which are built to similar standards.

One difference is in the "future proofing" of each system. A Pentium or Pentium Pro PC at pounds 4,000 is at the top of its product curve. A workstation at the same price is at the bottom of its range, and it is usually possible to upgrade it with a faster, or even second, processor later on. One manufacturer, Digital, straddles both sides of the divide. Its Intel/NT PCs can be upgraded to run the company's Alpha Risc chip without changing software.

A complete integration of the two markets is unlikely, however. According to manufacturers, PC power will start to tail off as performance increases become more expensive to achieve. Hardware prices will continue to fall but, insiders believe, markets will fragment. Sales of very high-end PCs are unlikely to exceed those of workstations, so the PC's greatest advantage, economies of scale, will be missing.

Does this all mean we will soon be able to make our own Toy Story on our low-cost workstations or high-end PCs? Technically perhaps - though sadly our lack of marketing muscle, distribution and possibly even talent will remain as problematic as ever.