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Facts about your computer clock.

This clock is made primarily from recycled computer parts. The face of the clock is a 14 inch diameter aluminum disk platter that is coated with a highly polished layer of iron dioxide that allows it to be magnetized to store information. The iron oxide is what gives the disk its brownish color. This particular disk platter came from an NCR model 658 disk drive. The disk pack this platter was part of consisted of 10 platters and was loaded into a washing-machine sized disk drive. The packs were removable allowing the company using the computer to load different packs containing different information, for example one pack could contain the accounts receivable, and another the payroll. The entire disk pack could hold 150 megabytes of information. That means this platter held 15 megabytes of data. Compare that to a typical laptop today that has a disk drive that fits in the palm of your hand and can contain 200 gigabytes (200,000 megabytes) or more. In addition to the much greater capacity, new disk drives are orders of magnitude faster than these old ones.

The pack typically would spin about 3600 revolutions per minute. At this speed, the outside edge of the platters in the pack would be travelling about 150 miles an hour. High performance drives today spin at 15,000 RPM.

The head that reads or writes the data on the platter doesn’t actually touch the platter but flies a few microns (millionths of a meter) off the face of the platter. As a comparison, a typical human hair is about 75 microns in size. If the head actually touches the platter, it gouges the iron oxide, and causes a head crash, which renders the disk drive and pack unusable.

An interesting fact about these washing-machine sized disk drives was that a devious programmer could write a program to access the disk in such a way so as to make the drive “walk” across the computer room floor, by causing the computer to access data on the very center of the pack then immediately access the outer edge and repeat this pattern many times. In such a way, the drive could literally bounce across the floor.

In the center opening of the disk is a circuit board that came from a computer. This board was part of what made up the central processing unit of the computer, the “brains” of the machine. This particular board came out of either a Honeywell or a Data General mini computer dated from the late 70s or early 80s. The term “mini computer” is an oxymoron today, as it was much less powerful than normal PCs of today, yet it was contained in a couple refrigerator-sized cabinets.

Please note that, even though the clock movement is new, the other clock parts (the platter and circuit board) are recycled. These parts are over 30 years old and so will have small scratches or dings in them (and dust).

The movement is quartz operated and is accurate to a few seconds each month. The movement operates on a single AA battery. Sorry, even though the clock shows a battery, it won't come with one. The battery shown was to make sure the movement is working correctly.

There is no shipping discount for multiple clocks because each is shipped individually in a foam-lined box for protection.

Computer Clock made from Old Mainframe Computer Disk and Circuit Board. 14 inches huge.


  • Handmade item
  • Materials: disk platter, circuit board, clock movement, battery, gold and black plastic numbers
  • Only ships within United States.
  • Feedback: 107 reviews
  • Favorited by: 4 people