[maemo-users] about process

From: cedric cellier rixed at happyleptic.org
Date: Fri Jul 11 15:57:14 EEST 2008
-[ Fri, Jul 11, 2008 at 12:41:37PM +0300, Zhenghe Zhang ]----
> About Process
> 	If you open an application , the system will create a process.

By "opening an application", one can means several things :

- Launching a new program (ie asking the kernel to basically load a new
  program in memory and to schedule it). See for instance the execve
  system call ('man 2 execve' on a fully fledged UNIX terminal) ;

- Showing the window of a program that's already in memory but that's
  not displayed at the moment.

You seams to be more interrested in the first case, so you should read a
book about UNIX operating system. The two references in this (quite old)
field are from Tanenbaum [1] and Bach [2].

You can also find on the web a quite still interresting document : the
commented unix source code by Lyon. 

[1]: http://www.amazon.com/Operating-Systems-Implementation-Prentice-Software/dp/0131429388/
[2]: http://www.amazon.com/Design-Operating-System-Prentice-Software/dp/0132017997/

> About N810
> 	At first,I add many repositories to the application catalogue
> Then I enter "apt-get update" in the osso-xterm .At last I open other
> "osso-xterm" and input "ps -awx". You will find there are many processes
> of "http". 

An "application" may consist of several colaborating processes. For
instance, apt-get may choose to "fork" several instances of an http
client to fetch various http servers in parallel. There's nothing to
worry about (untill it gets mad and forks hundreds of processes, which
_may_ be too much, sometimes).

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