Trouble with Computer Networks

Each new year since the birth of the personal computer has been hailed as “the year of the network”. This year is different. This time it is “ the decade of the network”. Do not hold your breath.

Market researchers at Dataquest in Silicon Valley think that American companies’ worldwide sales of the hardware and software needed to make personal-computer networks will grow by about 25% a year for the next two or three years. That is faster than the growth expected for personal computers themselves, but still not the boom that many had predicted. The step-by-step evolution of computer standards makes booms unlikely.

Standards are the key to successful networking. If they arc to communicate, computers must all speak the same language. Everything from how to establish a connection over the telephone to how to detect and correct errors must be agreed in detail at the outset. Devising flexible, reliable standards takes time; building reliable programmes based on them takes yet more. To see how complicated the process can be, look at what ought to be a fairly simple step in the evolution of computer networks: the ability to share files between machines.

Most of the basic problems of sending the strings of Os and Is that make up computer data from machine to machine have been solved. This does not mean that one machine can be plugged straight into another, or that networks do not suddenly and mysteriously break down. But there are, at least, procedures for diagnosing and repairing breakdowns and overcoming incompatibilities. Computer files are merely named collections of data. In theory, knowing how to send data should make sending files a snap. Unfortunately, in computing, things are never so simple. There are three or four different “standards” for sharing files. The differences between them lie not so much in how they solve the problem, but in how they set it.

Start with the Network File System (NFS) created by Sun Microsystems, the leading manufacturer of high-powered Unix workstations. NFS is probably the best means of swapping files between different types of computers. It enables one computer to get at files stored on another as if they were its own. That is much harder than it sounds.

Simply getting Os and Is from one machine to another provides no guarantee that the recipient can make sense of them. The string of Os and Is which denotes the letter "A” on most IBM mainframes means something else altogether on an IBM PC — as does the string which denotes the number 3.14. NFS must translate from one to another. It must also keep track of details such as the different naming conventions for files used by different machines. Most personal-computer file names, for example, can be only 12 characters long. Those for other operating systems can be much longer.

But NFS is less good at letting personal computers share files among themselves. It was created for, and often runs on, high-powered workstations. These use the Unix operating system which does lots of things that Microsoft’s DOS (the most popular operating systems for personal computers) docs not. For example, it handles the co-ordination necessary for a computer to do two things at once. And Unix, unlike DOS, ensures that the computers in a network do not all try to get at the same file at the same time. The inventors of NFS, therefore, did not have to worry about such things.

When it came to working with DOS, America’s Novell, the leading maker of personal-computer networks, built these features into its technology. So did 3Com, its biggest rival. Meanwhile, Microsoft, the largest personal-computer software company, is taking another approach. To make best use of today’s more powerful personal computers, it is promoting a new operating system, called OS/2. Microsoft has joined up with 3Com to develop a new technology to get OS/2 to work with networks; it is called LAN Manager.

Because Microsoft built both the operating system and the network software, LAN Manager probably makes best use of the facilities OS/2 offers for managing communication over networks. But it is, inevitably, different from both DOS-based networking software and NFS. So customers face several choices even about the humble task of getting computers to share files. There is a yet more bewildering array of solutions to even more complicated problems, such as getting computers to share work. No wonder many customers want a bit of time to think before they buy; meanwhile the decade of the network ticks by.