These large hard disks make it more difficult than ever before to back things up on a few floppy disks. (If you are not interested in doing the maths, I can tell you that a 1Gb hard disk would need nearly 100 floppies to back it up and hours of time to do it). The answer, of course, is to find something else.

The are a few criteria for this something that most of us would like. It would be nice to have something that could hold a large amount of data and was cheap, reliable, fast and small.

The choice seems to have narrowed to the following: a magnetic optical (MO) disk, a SyQuest, a Bernoulli, a Zip or a Jaz. Although other media are on the horizon, these are the only choices available today.

The sensation of the past year and one of the hottest items out there is the Zip drive from Iomega. Just when everybody thought that Iomega had seen its best days, the company came out with the Zip drive and then launched the Jaz.

The Zip drive is not only small, it takes disks that are only a tiny bit smaller than the normal 3.5 inch floppies that we all use today. The formatted size is about 100Mb, so it would take 10 of them to back up a 1Gb hard disk.

They are designed as floppies so they are not exactly fast but they are quite good. The plastic box the drive itself comes in, with its funky design, is certainly another reason for its success. Perhaps the best thing of all is that it is quite cheap - about $1,000. The original Zip was for the Macintosh and connected via a SCSI connector. Now there is also a parallel port version for the PC crowd, who often do not have a SCSI connector.

The Jaz drive is also from Iomega, but it is based on hard-disk technology, rather than that of a floppy.

The Jaz drive has been long awaited. They were extremely popular long before anyone saw one. The popularity of the Jaz is its size: one full gigabyte. The drives sell for just under $5,000 and the cartridges go for just under $1,000. Naturally enough, the Jaz drives are quite fast. I tried installing a Microtek Jaz drive on my Macintosh 8500 and had enormous problems. I took it back and waited for the real thing (Iomega's own drive) to arrive in Hong Kong and once again took the plunge.

This time it worked like a charm. The installation was over in three minutes. The Jaz is a truly wonderful thing that easily pays for itself if you need to back up a lot.

I was also one of the world's first users of the MO drive (I bought mine in Japan four years ago). At that time they were only 120Mb but today they go up to 230Mb.

Although Iomega has done a great deal of damage to the budding MO drive market, the MO still holds its own for those interested in keeping records. They are still reputed to be the 'safest' medium in that once they have been written to, they cannot be corrupted easily. Their speed is reasonable - faster than a floppy but not as fast as a hard disk. They can be had as internal drives on many machines.

SyQuest is the company that, in the words of one wag, 'really blew it'. There was once a time - only a few years ago - when SyQuest ruled the world of portable back-up. They originally had 44Mb cartridges and then moved to 88Mb.

Although they have lost a lot of ground to Iomega, they have produced a new drive called the EZ230. This is a drive that holds 230Mb of data, is cheap and relatively quick.

The Bernoulli drive was the first king of the portable drives, and was most popular about 10 years ago. It seems to have lost even more ground than the SyQuest, although Iomega still makes Bernoulli boxes. I have not seen one in Hong Kong.

One medium people seem to forget is the CD-ROM writer. This is a device that can write to a CD-ROM (only once, of course). Six months ago, a machine like this would have cost US$1,000. Today the price has dropped to half that.

The CD-ROM has a number of advantages and a few disadvantages. The advantage, of course, is that you are making a CD-ROM. This means there will be no problems with magnetic media and you can pop the disk in the CD-ROM drive on your machine and get the data whenever you want it.

It is not fast, of course, and it can take time to write the CD-ROM. However fast the CD-ROM may be, you must remember that it takes a while to set up a hard disk so that it can write to the CD-ROM.

Which of these should you get? Apart from the obvious question of how much you have to spend, the most important thing to ask yourself is if you need to be compatible with anyone else - your office or your printer, for example.

If that is important, the decision may have already been made for you. If that is not a consideration, then you must decide how much space you need, how fast you need the drive or cartridge to be and whether you will be using it only for back-up.

A Jaz cartridge, for example, can actually run applications in the same way a hard disk does.

SyQuest is supposed to be bringing out its own answer to the Jaz - the SyJet. It has been delayed but those who have had a glimpse of it say it looks extremely good. It will have to be at least that good to grab market share away from Iomega at the moment.

There is, of course, only one thing that is certain: six months from now, somebody else will have something that will be attempting to become a new standard. So what else is new?