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OT: EDSAC simulator



#4

It is not new and what it simulates is very old: the Edsac simulator, simulating the "electronic delay storage automatic calculator" of late 1940.

Why do I mention it? There comes a 'Sieve of Eratosthenes' program with it which visualises the sieve process. For me it was an eureka!

Ciao.....Mike


#5

Quote:
It is not new and what it simulates is very old: the Edsac simulator, simulating the "electronic delay storage automatic calculator" of late 1940.

Why do I mention it? There comes a 'Sieve of Eratosthenes' program with it which visualises the sieve process. For me it was an eureka!

Ciao.....Mike


I was told (by Professor Maurice Wilkes himself) that one of the first programs run on the original EDSAC produced a table of squares (I think by adding up successive odd numbers). This did not impress people as squaring was not hard to do on a (much simpler) analogue machine.

The next (?) program produced a table of primes, I guess this Sieve of Eratosthenes. This caused considerable interest as this was something that could not be done on an analogue machine and showed that EDSAC could do something new.


#6

Eratosthenes is not new, EDSAC is quite old (first kind of RISC?) but for me it was new to _see_ how the Sieve of Eratosthenes works. And this experience was so "Whow!" I allowed me this OT append.

This sieve process is an excellent example to show the difference between calculate and compute: with very little effort you 'find' the next prime like picking ripe fruits from a tree. After the 2 you get the 3 as only integer between 2 and 4 = 2^2, with the 3 you know all primes between 3 and 3^2=9, with the 5 you know all primes up to 5^2=25 and so on. And this insight I _saw_ the first time with the Edsac simulator. :)

Ciao.....Mike


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