Writing Threaded Applications

Abstract

Operating systems such as UNIX, Windows 95 and Windows 98 are able to run more than one application at the same time. At any one moment however, if you have only one processor, you are actually executing only one of those applications, but by switching between them quickly your computer is able to give the impression that it is working simultaneously on more than one of the applications. This can be a very efficient use of computer time, since if one application is updating a database it will spend a lot of its time waiting for the disk which is slow compared to the speed of the processor. This waiting time can be used to run a second application without slowing down the first. The scheduling of different applications is a feature of the operating system of your computer and you usually do not have a great deal of control over how it works.