Why is the hard drive the C: drive?

Hard Disk Drive
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Why Is The Hard Drive The C:> Drive?

The reasoning behind it is very simple, but the story behind it is much more complex.

Basically, it is because the A and B drives were dedicated to the floppy disk drives, which were what was used in the PC world, well before hard drives were mainstream. The reason why hard drives weren’t mainstream is the more complex part of the story.

IBM 350 RAMAC
IBM 350 RAMAC

The first commercial hard drive was actually in 1957, by IBM with the IBM 305 RAMAC, but this was back in the day when a computer took up an entire building and was used exclusively by the military or by universities.

At that time, hard drives grew in physical size when they grew in storage capacity. When the personal computer (PC) was born, some used perforated paper tape for storage, others used cassettes and others used floppy disk drives, it wasn’t until later that the hard drive was first used in a PC.

When we are talking about the perforated paper tape, we are talking about a card that had a series of holes punched out in it. When a card was fed into a reader, it would process that data. Often dozens if not hundreds of cards would be used (in order) to make up a program or a data file.

When we talk about cassette tapes, often it was the old audio cassette that was used. The Hewlett-Packard HP 9830 was one of the first desktop computers in the early 1970s to use automatically controlled cassette tapes for storage. Among home computers that used primarily data cassettes for storage in the late 1970s were Commodore PETTRS-80, and Apple II. The cassette had a capacity of around 660kb per side of a 90-minute cassette tape.

Cassette Tape
Cassette Tape

It wasn’t until the mid-1980s that the floppy disk became the storage medium of choice for the PC market. Back then we were talking 8″ in the early ’70s and the move compact 5 1/4 inch disk in the late ’70s. It wasn’t until the early 80s that the smaller 3 1/2-inch floppy disk became popular in the PC realm.

Now we are back to hard disk drives and the letter C. In 1956, The IBM 350 Disk Storage Unit Model 1 was announced, which was the first commercial storage unit to use magnetic disk storage, the technology behind hard disk drives. About the size of two refrigerators and weighing in at one ton, the 350 could store about 4 – 5 megabytes, depending on how it was calculated. (source 1 & source 2).

In the early 1960s IBM was working on removable hard disk packs that held 6 disks and had a 2.6Mb storage capacity. In 1970, General Digital Corporation (Western Digital today), invented error correction and built it into their hard drives. In 1973 the IBM Winchester Drive was introduced with three removable, sealed data modules. In 1979, IBM introduced its “Piccolo” drive, storing 64MB over eight disks (source)

The Hard Disk Drive (HDD) as we know it today, didn’t come around until 1980 when a young upstart company named Shugart Technology (incorporated in 1978 by Al Shugart) introduced a 5MB hard disk drive designed to fit into personal computers of the day. It was a scant 5.25 inches in diameter. The drive cost $1,500. It would prove popular enough to become a de facto standard for PCs throughout the 1980s. Shugart changed its name to Seagate Technology. Yep, that “Seagate”. (source)

IBM 3380 Disk Drive
IBM 3380 Disk Drive

While Shugart Technology was focusing on a smaller form factor with less capacity, other manufacturers like IBM were focusing on a 14″ disk drive that has a much greater capacity than the 5Mb Shugart drive. The IBM 3380 has an amazing 2.52Gb of capacity, but it was huge, weighing in at over 500 pounds, and had a price tag of $40,000, the Shugart drive cost $1,500 in comparison.

Today, data storage technology has evolved exponentially, where the storage capacity has grown and the size and price tag have shrunk.

Just to recap, it is a C: drive, because A: and B: were already taken by floppy drives. My how times have changed.

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Average Joe

Welcome to the Average Joe Weekly blog. This is basically my place on the web where I can help spread some of the knowledge that I have accumulated over the years. I served 10+ years in the Marine Corps on Active Duty, but that was some 25 years ago.

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By Average Joe

Welcome to the Average Joe Weekly blog. This is basically my place on the web where I can help spread some of the knowledge that I have accumulated over the years. I served 10+ years in the Marine Corps on Active Duty, but that was some 25 years ago.

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