We’ve seen how to compile a simple module. But what about writing a concurrent program? The basic unit of concurrency in Erlang is the process. A process is a lightweight virtual machine that can communicate with other processes only by sending and receiving messages. If you want a process to do something, you send it a message and possibly wait for a reply.
The first concurrent program we’ll write is a file server. To
transfer files between two machines, we need two programs: a
client that runs on one machine and a server that runs on a
second machine. To implement this, we’ll make two modules called
The File Server Process
The file server is implemented in a module called
afile_server. Just ...