Disc vs Disk

I am reminded of a long-term pet peeve by Spencer F Katt’s column in the 22 September 2008 issue of e-week magazine. In writing about technology there is both a Disc and a Disk. They are not interchangeable, and they don’t mean the same thing. Here’s a guide to getting it right.

First, a Disc (with a “C”) refers to optical media, such as an audio CD, DVD, Blu-Ray, and so forth. It doesn’t matter if the Disc is read only (ROM) or read/write (RAM or RW). All Discs are removable, meaning when you unmount or eject the Disc from your desktop, it physically comes out of your computer unless you have a wonky drive. Except for some specially made CDs, these are always round.

Second a Disk (with a “K”) refers to magnetic media, such as a floppy Disk, an internal or external hard Disk drive, or removable media such as Zip Disk or Jazz drives — and they don’t always use the word Disk. This term also applies to the RAM based flash-based Disk drives though this is a misnomer as they are not Disk drives but auxiliary storage devices. All Disk drives are read/write unless locked physically or by software using write-protect. Unmounting a Disk drive doesn’t necessarily cause the Disk to eject.

You can partition both types so that is not a valid determining factor. The confusion comes from the fact that a hard Disk drive is made up of magnetic Disc inside the drive that are round. They are called platters and they are Disc. Floppy Disk drives and Zip drives also have round Discs inside them. But a Disk drive doesn’t necessarily have Discs inside.

Impress your friends, know the difference, and get it right. Please. Thanks.

Leave a Reply