Category Archives: Storage

Hard Disk Insanity

The other day I found myself looking at an 8GB micro-SD card and marveling at how much storage has shrunk over the years. That in turn got me thinking back to the first computer I owned that had a hard drive: It was a Tandon (not Tandy) clone of the original IBM XT, with an 8088 processor. It looked something like this (apologies for the image quality — it was the only one I could find, and I’m guessing it was scanned from an old newspaper advertisement):

Tandon Computer

Image courtesy of The Probert Encyclopaedia.

This particular computer had a hard drive that was, to me at the time, unfathomably huge: Ten whole megabytes! Megabytes?!? That was more space than thirty floppy disks, and I didn’t have anything for my PC at the time that needed more than a single floppy!

Needless to say, the feeling that ten megabytes was a lot of space didn’t last long. Today my home file server has eleven terabytes of disk space. It would take 1.1 million of my first hard drive to provide that much storage. That got me thinking… Exactly how much space would 1.1 million of those ten megabyte drives take up?

Well, that first hard drive looked something like this:


Image courtesy of Computer History Museum.

That drive is actually a 21 megabyte Seagate drive, whereas mine was a ten megabyte off-brand drive, but the size is about right — roughly 5.75″ wide, 1.63″ high, and 8″ deep, for a total of about 75 cubic inches. For comparison to modern equipment, it’s about the size of an older CD-ROM or DVD-ROM drive.

1.1 million of those drives would take up about 82,478,000 cubic inches of space (or 47,730 cubic feet, or 1,768 cubic yards, or 1,352 cubic meters). That’s a lot of space. But how do you put it in terms that are easy to visualize?

Well, how about cargo containers? You know… the type you might see on a train, or on the back of a semi-truck, or stacked up on a boat or at a port?

According to Wolfram Alpha, it would take 25 forty-foot cargo containers to hold those hard drives. So picture 25 of these (actually, I’m pretty sure that’s a twenty-foot container, so picture something twice as big):


Image courtesy of Wikimedia Commons.

Alternately, according to Wolfram Alpha, this is roughly the equivalent of 0.73 times the cargo capacity of a Boeing 747 large cargo freighter, or 0.54 times the volume of an Olympic sized swimming pool.

And my current file server stores that same amount of data on six 3.5″ hard drives.