It's a 5MB hard disk from 1956!
In September, 1956, IBM launched the 305 RAMAC, the first computer with a hard disk drive (HDD). This hard drive weighed over 2000 pounds, and stored only 5MB of data. That's the size of one .MP3 song stored on your computer or IPod.
Now compare this to the little 4GB USB stick drive- the size of a pack of gum- you can put in your pocket or purse!
PS….To change the 3ft. round “platters” in case of problems, the unit had to be moved out onto the loading dock where a crane was used to slide the platters off the center hub. It used hydraulic fluid to drive the access arms/heads to the data on the spinning disks…..quite a sight when it would spring a leak…