What's a RAMAC you ask? A new Apple variant? No it was IBM's first hard disk.
I didn't see my first hard disk until 1971 in my computer lab in high school. I have no idea how much it stored, but if I remember it was about 12 inches across and about 18 inches tall. Down quite a bit in 15 years from the double refrigerator size RAMAC in 1956.
Read the article and then take a look at that hard disk drive in your desktop or laptop computer. You can really appreciate how far we have come since the first, revolutionary, tube-powered, 10 MB on two disk behemoth.
By the way, the actual 50th anniversary of the hard disk is September 13. How are you going to celebrate? ;-)