Your own PC still puts Sun in the shade

Network computers offer little more than a home computer. And they'll sting you into the bargain.

So network computers are the next big thing? That is what Sun Microsystems is hoping, after unveiling its prototype, the "Java Device". Out goes the usual chunky processing unit and in comes a neat little box with 8Mb of RAM. It still features a screen and keyboard, but there is no floppy disc or hard drive - those jobs are done by the central server.

Unfortunately, Sun's demonstration at the launch last month did not exactly wow the assembled hacks. The device needed rebooting each time the user wanted to run a new application - not exactly a step forward in computing. But the real doubts emerged when Sun tried to explain the supposed advantages of its system over conventional PC networks.

Initially, Sun is targeting its network computer (NC) at organisations using "intranets" - local networks serving one organisation.

"PCs are poorly suited for this purpose," says Martyn Lambert, the director of Sun's networking unit, "because you have to provide software and support services for each machine. Java does away with this and gives you infinite flexibility: you simply call up applications for specific tasks from the central server.

Updates or new packages can be added easily and support is carried out at the server end. At a stroke, you also rid yourself of the problem of untrained employees messing up the system. With no need for individual storage, hardware costs can be kept down."

It all sounds wonderful. But hold on.

First, you can already have all of this on your existing PC network, as Java works with most operating systems. With a bit of fiddling, you could adapt the network to control the distribution of software centrally, while still maintaining the PCs as independent units. And, of course, Java and the HotJava browser are available from the Internet free.

That is not the point, says Sun. Install a Java NC system and you save money. Not much, though. The price could be as much as pounds 1,000 per unit. Proven business PCs are available for little more than that now, with full networking capabilities. Moreover, if you install a Java NC system, you will have to fork out on a new central server.

It is in lower running costs, however, that companies will really see the benefits, according to Sun. The Java system will have "near-zero administration costs", compared to what it says is an annual average of pounds 2,300 per unit for a PC network. This sounds incredibly optimistic for a system using both new hardware and software. And even simple terminals can go wrong.

What really matters to IT managers, though, is performance. Can intranets cope with the extra load that will inevitably be generated? Yes, says Sun, because "most companies have high-capacity, 10-megabit networks". But Sun admits that it has not tested this in real work situations, where employees are downloading lots of applications from the central server at the same time. Even today, when intranets are mostly used for moving data and messages, they can become painfully slow with a lot of users connected.

The biggest fear of all is what happens if the network crashes.

Mr Lambert dismisses such concerns, saying that today's networks are extremely reliable and "many companies have a back-up anyway". But not every business can afford this and, as many will testify, networks do go down, however state-of-the-art the technology. If you are using PCs, though, you can carry on working and, if necessary, transfer data via floppy discs. With Java, you are stuck with a load of dumb machines, as useful as a car without petrol.

When pressed, one Sun spokesperson at the launch said: "We may bring out models with a floppy disc drive." But then why bother getting rid of your PCs?