CDC 6600 - Why so awesome?
paulkoning at comcast.net
Tue Jun 21 19:12:17 CDT 2016
> On Jun 21, 2016, at 5:39 PM, Noel Chiappa <jnc at mercury.lcs.mit.edu> wrote:
>> From: Swift Griggs
>> I see a lot of traffic about them on the list and I went out to
>> discover "why so cool?"
> One word - 'crunch'. The 6600 especially, but also its successors (7600, etc)
> were _the_ number-crunching monsters of their day.
Yes. The 6600 was an amazing engineering accomplishment. It had extremely fast memory for its day (under a microsecond access time, in 1964). It could run several million instructions per second. Floating point add in half a microsecond, multiply in one microsecond.
Lesser known things, like context switching ("exchange jump") in about 4 microseconds (!). And divide was done two bits per clock tick rather than the usual one bit per tick; essentially it was doing long division base 4 rather than base 2 as is common.
Also a disk drive (6603) that was WAY faster than its peers because it recorded data in 12 bit words parallel rather than using a serial bit stream. I believe something similar was also done in the Cray 1, but CDC had it a decade earlier.
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