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Faster than a hard disk? It's a ramdisk

technofile  by al fasoldt

Columns and commentaries in a life-long dance with technology
 

Simple gray rule



Faster than a hard disk? It's a ramdisk 


By Al Fasoldt

Copyright © 1990, The Syracuse Newspapers

Floppy discs are slow, and hard discs are fast. But what's even faster than a hard disc?

A ramdisc, that's what. All computers, even little Commodores and Ataris, can have ramdiscs, although they are much more common on standard PCs and the three "other" systems—Macs, Amigas and STs.

IBM calls its ramdisc a "virtual disc," and a few other companies refer to theirs as "ramdrives." But whatever the name, every ramdisc works the same way: A portion of the computer's random-access memory (RAM) is set aside and made to work like a disc drive. This distinction is ignored by the operating system (MS-DOS, for example); as far as it's concerned, the ramdisc is just one more drive in the system.

There are only two disadvantages to a ramdisc—it disappears when the computer is shut off (or when the power suddenly goes out), and it takes memory space away from other uses.

The second drawback is a minor one, and might not even be a problem at all if the ramdisc uses extra memory outside the normal range of the operating system. (That's how ramdiscs using extended or expanded memory work with regular PCs, and it's how the relatively huge 576k ramdisc works in one of my 64k computers.)

But the first disadvantage limits the usefulness of ramdiscs. You'd never want to store anything valuable in a ramdisc—unless, of course, you already have another copy of it somewhere else. However, you won't have any problems if you treat all the files on a ramdisc as temporary files.

What could these temporary files be? They could be dictionary and thesaurus files for your word processor, or they could be graphic images; they could be scripts for your telecomm program. (By the way, that's precisely what is kept on a large ramdisc in the PC we use here at the paragraph factory to run the Syracuse Newspapers Telesystem.)

Ramdiscs are usually easy to create. MS-DOS and PC-DOS users can set up a ramdisc using VDISK.SYS or RAMDRIVE.SYS or a similar program (check your DOS master discs). Mac, Amiga and ST ramdiscs are simple, too.

Ramdiscs are helpful because they are super-fast. I tested a ramdisc in one of my computers and compared its speed in writing files and reading them back. In one of the tests, which reads many sections of the disc, one of my floppy drives took 1,098 seconds, and another floppy drive took 1,039 seconds. One of my hard drives took 89 seconds—a vast speed improvement over the floppies—but the ramdisc took only 3.7 seconds.

That makes the ramdisc 12 times faster than the hard disc and 304 times faster then the floppy.


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