Gene Amdahl

Gene Amdahl has died. For decades he was, and now will be forever one of the greatest computer technologists of history. The NYTimes has a good obituary. He was one of the primary engineers behind IBM's System/360 which became one of the most successful mainframes ever. 

Amdahl's Law is simple yet quite fascinating. It explores the notion of how we think about parallel computation, or even more generally, performing a series of tasks, so there are some relevant considerations for assembly line process and/or people management. It puts a theoretical limit on the speedup we can achieve in a system, and those limits are startlingly low. For example, lets say you have a task, of which 50% is parallelizable (can be processed side by side). Amdahl's Law says it doesn't matter how many workers you have, you can never get a speedup beyond 2x. It makes no difference if you have a thousand or a million workers on a task which is 90% parallelizable: you have have an upper bound on a 10x speedup. It's a formulation of the classic law of diminishing returns, with a very straightforward equation to back it up.