[deathanatos]

> Now, let’s go back to that first hard drive, the IBM RAMAC from 1956. Here are some specs on that thing:

> Storage Capacity: 3.75 MB

> Cost: ~$9,200/terabyte

Those specs can't possibly be correct. If you multiply the cost by the storage, the cost of the drive works out to 3¢.

This site[1] states,

> It stored about 2,000 bits of data per square inch and had a purchase price of about $10,000 per megabyte

So perhaps the specs should read $9,200 / megabyte? (Which would put the drive's cost at $34,500, which seems more plausible.)

[1]: https://www.historyofinformation.com/detail.php?entryid=952

[birdyrooster]

Must've put a decimal point in the wrong place or something. I always do that. I always mess up some mundane detail.

[S_A_P]

Did you get the memo? Yeah I will go ahead and get you another copy of that memo.

[acdha]

https://en.m.wikipedia.org/wiki/IBM_305_RAMAC has the likely source of the error: 30M bits (using the 6 data bits but not parity), but it rented for $3k per month so you didn’t have a set cost the same as buying a physical drive outright - very close to S3’s model, though.

[nijave]

I think this is still IBMs license model (at least a few years ago). It was explained to me you basically license a certain amount of compute even though the hardware is in your data center and you pay overages if you exceed your licensed throughput.

Since you license a fixed amount, there were projects at the company looking at running batch/non time sensitive jobs on the mainframe since it was effectively free off peak (I guess power cost was trivially compared to licensing).

[mkesper]

You had online jobs during the day and batch at night then. That's why you always had to have one night between. Obviously doesn't work when load is 24/7.

[andywarfield]

oh shoot. good catch, thanks!