Abstract

It is widely acknowledged that concurrent programming is difficult. Yet multicore architectures make concurrent programming essential. If we understand why concurrent programming is so difficult, we have a better chance of solving the problem. Sutter and Larus observe [17] “humans are quickly overwhelmed by concurrency and find it much more difficult to reason about concurrent than sequential code. Even careful people miss possible interleavings among even simple collections of partially ordered operations.” Yet humans are actually quite adept at reasoning about concurrent systems. The physical world is highly concurrent, and our very survival depends on our ability to reason about concurrent physical dynamics. The problem is that we have chosen concurrent abstractions that do not even vaguely resemble the concurrency of the physical world. We have become so used to these computational abstractions that we have lost track of the fact that they are not immutable. I argue that the difficulty of concurrent programming is a consequence of the abstractions, and that if we are are willing to let go of those abstractions, then the problem will be fixable. New abstractions for computing would seem to imply a need for new programming languages. However, this is not necessarily the case. I will argue that concurrency models can operate at

Citations