[...] Multiple processor architectures introduce a new class of programming problem. Writing software to get the best performance from multiple-processor systems is far from straightforward. Issues such as synchronization, load balancing, memory protection and task distribution place new demands on programmers and those building tools that are used by developers.

Chip builders have concentrated on the use of multi threading. Intel, for example, has invested heavily in multi-threading technology with its thread building blocks (TBB) library extensions to C++. But the validity of multi threading is under attack. Veteran programmer Knuth said in a recent interview that multithreading may not be up to the task and could fail. As such, he is "unhappy" with the current trend towards multi-core architectures.

[...]Knuth — the author of the seminal programmers' manual The Art of Computer Programming and a Turing Award winner — has to be taken seriously on this. And he is not alone. Sun Microsystems' director of web technologies Tim Bray, one of the team that created XML, has also criticized multi threading. Bray said that, while he once favored the approach, he had now turned away from it. Elsewhere the criticism of multi threading is even more direct.

The monkeys were deprived of sleep for 30 to 36 hours and then given either orexin A or a saline placebo before taking standard cognitive tests. The monkeys given orexin A in a nasal spray scored about the same as alert monkeys, while the saline-control group was severely impaired. The study, published in the Dec. 26 edition of The Journal of Neuroscience, found orexin A not only restored monkeys' cognitive abilities but made their brains look "awake" in PET scans. Siegel said that orexin A is unique in that it only had an impact on sleepy monkeys, not alert ones, and that it is "specific in reversing the effects of sleepiness" without other impacts on the brain.

Adding more processing cores to a CPU should have been a relatively painless evolution of computer technology but it turned out to be a real pain in the ass, programming wise. Why? To understand the problem, we must go back to the very beginning of the computer age, close to a hundred and fifty years ago, when an Englishman named Charles Babbage designed the world's first general purpose computer, the analytical engine. Babbage was a mathematician and like most mathematicians of his day, he longed for a time when he would be freed from the tedium of performing long calculation sequences. All he wanted was a reasonably fast calculator that could reliably execute mathematical sequences or algorithms. The idea of using a single fast central processor to emulate the behaviors of multiple small parallel processors was the furthest thing from his mind. Indeed, the very first program written for the analytical engine by Babbage's friend and fellow mathematician, Lady Ada Lovelace, was a table of instructions meant to calculate the Bernoulli numbers, a sequence of rational numbers. Neither Babbage nor Lady Ada should be faulted for this but current modern computers are still based on Babbage's sequential model. Is it any wonder that the computer industry is having such a hard time making the transition from sequential to parallel computing?