Can one program have multiple processes?

after reading and searching about OS and process an开发者_C百科d threads, I checked on wiki and it said,

A computer program is a passive collection of instructions, a process is the actual execution of those instructions. Several processes may be associated with the same program; for example, opening up several instances of the same program often means more than one process is being executed.

Now is it possible for a program to have more than one process and I am not including the possibility of running more than one instance of the same program. I mean one instance of one program is running, is it possible for a program to have more than one process? If yes, how? If no, why not?

I am a newbie in this, but damn curious :) Thanks for all your help..

Yes, fairly obviously - you can run two or more copies of most programs - I routinely have about 5 copies of vim running, and each of those is a separate process. As to how, the OS loads the executable file, creates a process and then tells that process to start executing the file contents.

It is most definitely possible but a desktop application might not be a good example and I think this is the source of your confusion.

Consider a webserver instead (NginX or Apache). There is one master process and multiple worker processes at work. The master process "accpets" the work , so to speak, and delegates it to the workers. Both NginX and Apache could be configured to any number of worker processes.

At our company we are in the business of delivering a SaaS that helps businesses have an online chat with their visitors via their websites. The back-end part of our system has multiple "service"es communicating with each other to accomplish the task. Each service has multiple instances running.