According to industry research consultants Inteco, five years ago there were only 19,000 CD-Rom drives in use in the UK. By the end of last year that had grown to 809,000 and by the end of next month the figure will be 2.5 million. And that is just a start: now, 8.5 per cent of British homes have a computer with a CD-Rom drive. By 1999, Inteco reckons, a third will. It is fairly certain that millions of computers will be sold only because they have these drives - the CD-Rom is converting the computer from a boring business machine into a consumer product, a source of education and entertainment.
The launch of Windows 95 has shown how fast the CD-Rom is gaining ground on traditional disks. According to trade magazine reports there are warehouses filled with floppy disk versions of the new software. Microsoft expected 40 to 50 per cent of sales to be of CD-Roms. Some distributors report that the figure is 80 per cent. Why? Probably because installing from one CD-Rom is a whole lot easier than it is from 13 floppy disks.
The CD-Rom (compact disk - read-only memory) has been around since 1986. It grew out of the audio CD, taking advantage of the fact that anything that could be "digitised" - or turned into a string of on-off signals - could be stored on a compact disk. Sound could be digitised, of course, but so could text, pictures, graphics and even video - the elements of multimedia. That meant the CD could behave just like a computer disk, with one difference: where a floppy disk might store one megabyte of data, a CD could hold more than 600mb.
The potential was obvious, but the technology to digitise and play multimedia had yet to be developed. The first disks were just large collections of text - technical data that had previously occupied yards of shelf space could be stored on a single CD, and played on special drives linked to a computer.
Bill Gates recognised early the consumer potential of CD-Roms, and Microsoft launched its first CD-Rom in 1987. But Apple has since stolen its lead. In 1992 John Sculley, then chief executive, committed Apple to building CD-Rom drives into its machines at cost price to help kick start the market. Today all new Apple desktop computers have CD-Rom drives, while, according to Inteco, only 35 per cent of PC clones do.
One of the limitations of early CD-Roms was that computer drives could not "read" them rapidly. Transfer was at 150 kilobytes a second, which meant it took more than an hour to read the 650mb on a single disk. Although double-speed drives appeared in 1991, they were slow to take off, and it was only last year that they finally dominated the market. Speed is now king: this year quad speeds will take more than 50 per cent of the market, and six-times speed drives have arrived. They are still expensive, though by Christmas 1996 they may well be the standard.
Personal computers are not the only machines capable of playing CD-Roms. Philips launched its CD-i in the late Eighties: this plays multimedia through a television set rather than a computer. And the new specialist games platforms, the Sony Playstation and Sega Saturn, use CD-Roms rather than cartridges.
CD-Roms can even be used to play back VHS-quality video. Thanks to advances in compression technology, it is now possible to jam a complete film on to one CD. That is why this Christmas several companies are offering hi- fis with a video CD unit that can play Four Weddings and a Funeral on the telly.
Computer games developers have been given a new dimension to play with - the sheer volume of data they can include. For example, Electronic Arts' Fifa 96 football game has a commentary by John Motson. The game lets you select from 3,500 players, and there are 18,000 audio samples from Motson that are stitched together to make the commentary. While it is not always perfect, 95 per cent of the time you cannot hear the join. It is eerie to hear Motson say: "And Giggs down the wing to Robertson," and to know that if you had chosen a different team, you would have heard "And Giggs down the wing to Bowman".
In entertainment the CD-Rom is nurturing a new art form. Interactive movies, where video clips and game action are mixed together, are beginning to become as important to the entertainment majors as films. Electronic Arts' Wing Commander IV, which will be in the shops this Christmas, will come on seven CD-Roms and will have cost more than $8m to produce. Wing Commander III, starring Mark Hamill (of Star Wars fame), Malcolm McDowell and John Rhys-Davies and which cost around $5m, is Electronic Arts' biggest CD-Rom seller to date.
The CD-Rom still has a way to go. Systems that allow you to record your own disk are dropping rapidly in price. Panasonic has a system called PD for just pounds 550: the disadvantage is that the disks you record will play back only on another PD system. If you want to record CD-Roms and play them on an ordinary drive, systems are available for less than pounds 1,000.
CD innovation will not stop there. Pioneer has just introduced a very nice CD-Rom drive that will take six disks at a time so you do not have to get up and install the disk you need all the time. And so it goes on.
Having said all this, the CD-Rom is under threat. First, a new type of disk that is due to hit the market next year will store 9 gigabytes of data - 13 times more than a standard CD-Rom. That will gradually chisel into the market.
Longer term it is online information that poses the biggest challenge. As communications charges come down and the speed of data transfer rises, there must come a point at which we decide to access all the data we need over the telephone line. It makes no sense for us to have all the information we might ever need stored on CD-Rom - far better to dial up a computer and download only what we need. Not only will this be cheaper, the information will often be more up-to-date.
Already in the US one CD-Rom manufacturer is working with a cable company to create a system by which cable subscribers can access a couple of dozen CD-Rom titles. For its part, Microsoft has a fully functioning version of its Encarta encyclopaedia available on the Microsoft Network, and offers an "update-by-Internet" service for the CD-Rom version.
Does this mean you are wasting your money buying a CD-Rom drive? Unequivocally no. You can buy a reasonable drive for less than pounds 150. There are wonderful things available on CD-Rom, and do you really want to install your next generation of software from 35 floppy disks? The CD-Rom has become the great enlivener and great enabler of computing technology of the past year or two. For the foreseeable future, CD-Roms can only become more and more fun.Reuse content