One Process, Multiple Threads

Abstract

The ability to add processes, especially to load different applications in them (which you can with commands we didn’t talk about last chapter), is a useful capability. But there are some downsides. Getting one process to communicate with another, for example, involves an outside mechanism. You can write to a file and have the second process read that file in, so long as you have some kind of file locking in place, so reads and writes don’t happen at the same time. You can use a standard UNIX/Linux tool called a pipe, which looks like a file that is write-only to one process and read-only to the other. There are ways around the communication problem, many well established from the dinosaur UNIX days.