Brave New Hard Drives

The IBM System 360 Model 40 mainframe computer, April 7, 1964
AP (file)
File that, would you? There was a time when your only choice was to stuff a piece of paper in a drawer somewhere (and hope that later, you'd remember where).

Today, we take digital storage for granted but the fact is, the possibilities for storing all sorts of files – words, numbers, images, music, video, and more – have been growing by leaps and bounds for the past fifty years, as computers themselves shrunk from forests of machines filling huge rooms to thin pieces of plastic apt to slide off the laps of careless users.

When PCs first came out, there were no affordable hard drives. Even when the IBM PC was introduced in 1981, it had only a 160 kilobyte floppy drive. The first mass market PC with a built-in hard drive was the IBM XT, which came out in 1983, with a whopping 10 megabytes of storage.

The original 160 KB floppy could store about 164,000 bytes or characters – enough for about 137 pages of double spaced text. Forget about graphics, music or video. That 10 megabyte drive back in 1983 could store about 8,800 pages of text.


Click here for Larry Magid's podcast interview of IBM's Craig Butler,
discussing 50 years of leaps forward in computer hard drives
and predictions for future developments in digital storage.

The comparison to today's PCs, most of which are likely to have an at least 40 gigabyte hard drive, is dramatic. High end PCs tend to have 500 GB hard drives, which can store nearly 550 million double spaced pages or more than 128,000 songs or high resolution digital photos.

And Seagate makes a PC hard drive that stores 750 GB.

While it took until the 1980s for hard drives to migrate down to PCs, they were actually invented back in the 1950s. The first hard drive used in a commercial computer was unveiled by IBM 50 years ago this week on September 13, 1956.

That first drive assembly, called the "IBM 350 disc storage unit" was part of the IBM 305 RAMAC computer, according to Craig Butler, IBM's manager of disc storage products.

The device, according to Butler, made it possible for businesses to access data on a random basis without having to predefine the order of access - similar to the way you would locate a song on a cassette tape.

The storage process was called "continuous accounting" because it allowed users – that is, businesses who could afford it - to process data right after it was loaded into the computer.

The device, which stored five million characters (a bit short of 5 megabytes), cost $35,000 in 1956 dollars and stood 5 feet tall, a little less than 6 feet wide and 2.5 feet deep.

Storage capacity for drives is measured in areal density – the number of bits per square inch of storage surface. The areal density of today's drives, according to Butler, is 64 million times higher than it was back in 1956: an increase of 46 percent per year. Butler expects drive capacity to continue to grow rapidly for the next couple of years but eventually slow down.

Still, consumers can expect to see significant improvements in capacity over the next few years. A relatively new breakthrough is technology that increases areal density by aligning bits of data vertically or perpendicularly, instead of horizontally.

Prior to this innovation, bits were stored on flat sections of the platter. Storing them vertically is a little like erecting a high-rise building, enabling engineers to pack more per inch into the total amount of disc real estate.