The Mess Hall

nothing illegal here... move along now.

I was thinking the other day about various computer laws, such as parallel computing. Back in the day of single core CPU's, one such law determined the maximum amount of CPU's before parallelism slowed down, if I recall, that number was 5 - 5 CPU's and you lose any benefits and actually slow down calculations.

Then there was another that predicted CPU's would double in speed every 18 months - Moores law.

I'm sure there's loads more, size, ram, bus types etc, but my old plaque infested brain, killed by smoking and alcohol, just can't think of their names and details.

Anyone else similarly affected, or can you remember them?

They're not really relevant TBH. There is only so much speed you can gain from parallelisation. Not every software job is suitable or capable of being broken into many concurrent micro-jobs.

you're right infinite, and to be honest it's just curiosity about other laws that drove me to look.
found this on wikipedia http://en.wikipedia.org/wiki/Moore%27s_ ... second_law

according to intel moore's law will end in 2013-2018, thats when fabrication gets smaller than we can make them, transistors are almost at the atomic level now. The only thing left after that is bigger chips or stacking.

I actually thought speeds had plateaued a bit already and people where just whacking more cores on?

YorkshirePud wrote:I actually thought speeds had plateaued a bit already and people where just whacking more cores on?

Yeah speeds are rising, but no where near as quickly as years gone by.
I was curious because 8 core's are effectively 8 CPU's and I wondered how they got passed Amdahl's law. I was told many years ago that 4 was the maximum number of CPU's before you start working backwards.

I can only assume a system similar to the PS3 SPU, 9 cores, 8 do the work and one controls the flow of work.