Mystery Picture Answer!

I am holding an "original 26" diameter hard drive platter from an early storage device, the Control Data Corporation 6603 Disk File Controller manufactured by Bryant-Excello circa 1967"

I was visiting a friend one day at her father's house. This was hanging on the wall of the garage and I had to get a picture! It was quite heavy. Her father used to be a programmer in the olden days (60's). She told me that when they were programing for that computer they had to take the time that the disk rotated into consideration! You can see another example of the Hard Drive here.

If you are interested in more information about that antique computer here is another link