Why is the Default OS Drive Assigned the Letter C?

At LockerGnome.net, IamTechCrazy writes:

I’ve always wondered why the default letter for Windows OS drive is “C.”

FloppyThis is a good question, and the answer date backs to the early days of personal computing. Believe it or not, personal computers didn’t start out with a hard drive the way we know them today. In fact, entire operating environments and programs existed almost entirely on external media, if they weren’t soldered directly into a board’s hardware. Software back in the early days was very simple compared to today’s massive programs. What we now use gigabytes to accomplish was once limited to a handful of bits and bytes.

When personal computers became more mainstream and running programs through punch cards and paper reels was replaced with floppy disks (which actually were floppy at first), these drives assumed the designation of drive A and B. Many computers had two floppy drives installed to allow for variances in standards. Back then, not every floppy drive adhered to the same standard. The size of floppy disks changed from 8 inches to 5.5 inches and, eventually, the 3.5-inch floppy we commonly associate with the old storage technology.

When hard drives became more commonplace with greater capacity, they were assigned a standard drive designation of C. A and B continued to be reserved for floppy disks until the late 1990s when most OEMs dropped floppy drives in favor of CD-ROMs and writable compact disc drives. It wasn’t until the early 2000s that floppy drives were considered obsolete.

Up until 2003, this was a common system drive breakdown.

  • A: Floppy Drive
  • B: Floppy Drive
  • C: Hard Disk Drive (HDD)
  • D: CD-ROM

Floppy drives became less popular for primary software storage and more commonly used to create driver and boot disks. You might insert a floppy disk into your system to troubleshoot an issue or run a very basic operating environment for diagnostic software (like SpinRite). As the price of USB thumb drives went down, the desire to have a floppy drive available for these needs also dropped dramatically. By the mid 2000s, these drives were largely phased out for all but nostalgia.

Software designed over the past 20-30 years has defaulted to the C drive as the primary operating system. This has endured over time because it’s a standard that doesn’t really need to change for the sake of change. Software almost universally expects an operating system to exist on the C drive, and changing this designation now would result in a number of issues. So, why fix what isn’t broken?

You can still put floppy drives to good use. There are a few open source projects out there (including some imaginative hardware hacks) that can turn your floppy drives into musical instruments. Just see the video above for an example.

Image: Wikimedia

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Chris has consistently expressed his convictions and visions outright, supplying practical information to targeted audiences: media agencies, business owners, technology consumers, software and hardware professionals, et al. He remains a passionate personality in the tech community-at-large. He's a geek.