ONE day this will happen to you.
You're typing along or loading a new program. Suddenly, the computer flashes back: "Disk Full" or "Insufficient disk space." That's a scary message. Old Faithful has just run out of room.
I know this will happen to Old Faithful because I've spent the last few weeks playing with one of its descendants: a multimedia computer on loan from CompuAdd. Multimedia computers merge text with sound and images. It's a little like turning a book into a movie. It also takes up gobs of disk space.
One of my first multimedia experiments was to record 37 minutes of an interview onto the computer's hard disk. I wanted to record more, but the machine ran out of room. I couldn't believe it! A brand new, 120-megabyte computer couldn't hold the equivalent of a dime-store cassette. And I was just working with sound! Color video would have devoured that disk in seconds.
Hard drives fill up with other stuff too. My first desktop computer - an IBM XT - came with 20 megabytes, plenty of room for the limited, text-based programs of that era. When I needed more room, I got a 386-class computer with an 80-megabyte drive. That was all the space I needed, the salesman assured me. Within two years, that disk ran out of room too. My disk-hungry Windows programs, based on graphics instead of text, didn't fit anymore.
Fortunately, there are solutions to crammed disks. You can delay the problem by buying a bigger hard disk or compression software. Or you can solve the problem with removable storage. The choice depends on your needs. Because I experiment with lots of software, I opted for removable storage. Down the road, I think most of you will too.
The shift is already under way.
Two years ago, the Iomega Corporation sold its removable Bernoulli drive to users who wanted to lock up their data files or move them from place to place. Some users bought Bernoulli drives to back up their hard disks.
But as prices fell and speeds increased, the Bernoulli has become a kind of second hard drive. Today, "the No. 1 reason people buy a Bernoulli drive is that they run out of space," says James Jonez, Iomega's product manager.
Removable storage works like a huge floppy disk, but it stores at least as many data as today's average hard drive. Keep changing disks and your computer's capacity is theoretically unlimited.
Iomega and its competitors use traditional magnetic media for their removable systems. They are reliable and relatively cheap. I'm using a 90-megabyte Bernoulli Transportable Pro to store this article. With a street price of under $700, it's more expensive than a 90-megabyte hard drive. But the cost goes down with extra Bernoulli disks. A three-disk pack costs a little more than $400, about a third less than a smaller 210-megabyte hard drive.
There are drawbacks to removable drives. My Bernoulli runs a little slower than my hard drive, even though the company claims its caching software makes it run just as fast. Another drawback is that the disk cache requires 12 kilobytes of precious random-access memory or RAM.
An intriguing alternative is an optical disk drive. Robert Abraham, vice president of a California management-consultant company called Freeman Associates, estimates that 3.6 million such drives are installed worldwide. Most of them are CD-ROM units, which can display only the data that a publisher has put on them.
But users want to store their own data. Their needs may be met by magneto optical or MO technology. MO drives should double, perhaps quadruple, their share of the mass-storage market by the end of the decade, Mr. Abraham says. They pack an enormous amount of storage for desktop computers. A single disk can hold 650 megabytes or more of information.
Currently, MO drives are two to three times slower than hard drives and they're costly - starting at just under $2,000. That's more than I'm ready to pay for mass storage.
But prices will come down, since the world's major electronics companies are all competing in MO. Down the road, almost everybody may be able to afford a gigabyte of storage on the desktop.
* Send your comments on this column to CompuServe (70541,3654) or Prodigy (BXGN44A)