Multiple instances of the same application with different PID's

pjoshi · 11-24-2009, 04:02 AM

Hi,

Top command shows the multiple instances (min 7-8 instances) of the same application with different PID wherein the PS command shows only one instance of an application.

I would like to know whether memory (RAM) utilized by the application is only once as shown in 'SIZE' column or multiplied by the number of instances shown in the Top command.

If this is the case a large volume of memory is getting blocked in this process. How can I overcome this?

Thanks in anticipation.

Prasad

business_kid · 11-24-2009, 04:31 AM

try pstree with fancy options
pstree aux?

slimm609 · 11-24-2009, 06:34 AM

Please provide more infomation on things like this.

The OS, Program name, etc. Certain programs spawn children processes so it could be completely normal.

pjoshi · 11-24-2009, 11:54 PM

Slimm609,

Thanks for the suggestions. The OS we are using is RedHat Linux with kernal 2.4.21. The programs for which the Top command shows multiple instances are Open Office 3.0, Thunderbird 2.0, Netscape, Mozilla Firefox etc

Prasad

business_kid · 11-25-2009, 03:36 AM

That's kinda normal. In windows, everything is in the one exe, and when it is hacked, the hacker can do anything - hence hacks which read off the address book and mail them copies of the virus.

In linux, each program does one bit only as a rule. If that's hacked, the hacker only has access or permissions for one tiny area (e.g. incoming mail). Program suites observe this rule by using separate processes and libs for separate functions.

The behaviour you describe is not a problem. Investigate linux programming yourself.