Re:Hans Peter Luhn and the Birth of the Hashing Algorithm
by bogomipz on Wednesday January 31, 2018 @01:07PM
(#16275979)
>"Seek/read time on these machines was on the order of a second, so a 10 level binary search could take around 10 seconds of total time. Unfortunately for IBM, this wasn't an improvement over the best human-driven manual lookup processes"
I am curious what human-driven manual lookup processes existed that could be in a single second?
Re:Hans Peter Luhn and the Birth of the Hashing Algorithm
by mschaef on Wednesday January 31, 2018 @02:38PM
(#16276849)
A tub file:
https://en.wikipedia.org/wiki/Tub_file
(Note that the overall search takes 10 seconds, not the one second of an individual seek... so the human had a bit more time to be competitive with the disk than a single second. :-) )
Re:Hans Peter Luhn and the Birth of the Hashing Algorithm
by brian_cloutier on Wednesday January 31, 2018 @01:49PM
(#16276395)
I have no information as to what the parent is referring to but 2^10 is 1024. That seems roughly in line with what a double-page spread of a phone book could show you; I don't think it's unreasonable that a trained human could search through one of those in under 10 seconds.
Back in 1953, IBM was investigating disk storage for record retrieval in large volumes of data. Seek/read time on these machines was on the order of a second, so a 10 level binary search could take around 10 seconds of total time. Unfortunately for IBM, this wasn't an improvement over the best human-driven manual lookup processes... which is an issue if you're trying to sell/lease expensive computer hardware.
With this as motivation, Luhn then essentially invented what we now would know as a hash table, which was key to the 1956 RAMAC release.