Back in 1977, I went to work for IBM as a technician working on the IBM 3350 Disk Drive pictured below.
The picture actually shows a "string" of 4 of them connected together (typical installation) which consists of a controller, 2 slaves and an alternate controller. This "string" of drives was the length of 4 washer/dryer sets placed side-by-side, required 220VAC to operate, stored a whopping 2.4GB of data and cost in the vicinity of $80,000. At the time, these disk drives were considered to be the best drives available.
Yesterday, I bought a 10TB 3.5" disk drive for my PC for $329. It can store the equivalent of about 4,000 of these strings of 3350 Disk Drives.
Absolutely Root, the storage capacity of those tiny microSD cards that are the size of the fingernail on my pinky finger is mind boggling.
@Celery - If you tried to tell them back then about the power we now hold in our hands with the average smart phone, they would have you committed twice as fast!