And to fetch the information? Then you simply type out commands instructing the head to “read” from the disk to the RAM.
It’s much like a tape recorder storing your voice magnetically. But a disk drive can read or write information much more rapidly than a tape-recorder-style arrangement could. That’s because the disk spins so rapidly—hundreds of revolutions per minute.
Why twin disk drives, however?
There are two reasons:
1. You can quickly make safety copies of valuable disks—something that’s more of a hassle with single-drive computers like the bare-boned Macintosh.
2. You can more easily work with long electronic documents.
With one drive I’m storing WordStar and a number of other goodies that take up almost all the space on the floppy; there’d be hardly any room for the information I’m typing out. All this is happening on my “A” drive.
The[The] “B” drive is my data disk, devoted entirely to storage of my writing. I can easily squeeze the equivalent of about fifty pages of double-spaced typing with WordStar, which is one reason I bought a Kaypro instead of an Osborne. Brand O’s earlier versions could store only half that amount of material. Before buying a computer, you should always analyze your paper records in terms of “K.” Each K stands for 1,024 characters; and that includes letters, numbers, punctuation marks, and spaces in between. A double-spaced page of typing might be 66 (the number of columns across each line) × 28 (the number of lines), or 1,848 characters. Bingo! That’s 1.8K, plus a little slack for safety. Since Andy Kay allowed 191K of working space on each floppy, I’d have enough room for a document some hundred pages long, except that WordStar makes an electronic carbon copy for additional security. So my actual working space is around 50 pages. That’s easily enough for this chapter to fit on one of the Kaypro II’s floppies. And newer floppy disk[disk] drives can accommodate more than 2.5 million bytes.
Although the Osborne and Kaypro both used twin drives, there were also major differences between the two—beyond the double-density feature that allowed Kay to squeeze twice as much material on each floppy.
Osborne’s first computer, for example, came with only a five-inch monitor. “Adequacy is sufficient,” he once said. “All else is irrelevant.” It was a neat excuse for his early machine’s limited disk space and for the five-inch, black-and-white screen, which could display only 52 columns and which wasn’t as kind to the eyes as green.