Remembering RAMAC

[Paul Koning]

I looked at some old docs to make up bits of a "technology timeline".
Mostly it looks like a pretty smooth evolution from the RAMAC starting
point (1200 rpm, 5 MB, 10 kbytes/second transfer rate, 500 ms average
seek).  But there is one very conspicuous exception, which is (not
surprisingly) the first disk drive for the CDC 6600.

The 6638 came out around 1964 or 1965 (not sure about the exact year).
It spins at 1200 rpm just like RAMAC, but the capacity is 100 MB,
average seek is 100 ms, and transfer rate is a whopping 1 MB/s!

(By contrast, a drive like the DEC RP03, which came out in 1973 or
thereabouts -- pretty much identical to the IBM 2314 -- has a capacity
of 40 MB, and a transfer rate of just 260 kB/s.  So about 8 years
earlier CDC had 4x the transfer rate.  Admittedly the 6638 is a much
bigger machine, looking more like a RAMAC than like the 2314 disk pack
drives, but still, that's impressive.

	paul