Fwd: eXpOs stage 22 assignment 2

[Murali Krishnan]

---------- Forwarded message ---------
From: senan jude <senan_b...@nitc.ac.in>
Date: Sun, Oct 25, 2020 at 8:40 PM
Subject: Re: eXpOs stage 22 assignment 2
To: Murali Krishnan <kmu...@nitc.ac.in>

Sorry sir I'll send it now

On Sat, Oct 24, 2020, 7:57 PM Murali Krishnan <kmu...@nitc.ac.in> wrote:

Attachment missing.   

On Sat, Oct 24, 2020 at 7:21 PM senan jude <senan_b...@nitc.ac.in> wrote:

Sir

      In the assignment 2 of stage 22 the parent program (attached below) is supposed to print the pid of the 8 resulting process of 3 consecutive fork system calls. But as I run the code half of the pid values were 0. When I checked the code the return value of fork system call is printed by each process. But this value is not the pid. In the last fork call the existing 4 process are made in to 8 and those former 4 process have pid of child as return value, and the new 4 process has the value 0. So should I change the provided code? Thanking you in advance.

Sincerely

Senan Jude

B180706CS

CSE B

[Karunakaran Murali Krishnan]

Sir

      In the assignment 2 of stage 22 the parent program (attached below) is supposed to print the pid of the 8 resulting process of 3 consecutive fork system calls. But as I run the code half of the pid values were 0. When I checked the code the return value of fork system call is printed by each process. But this value is not the pid. In the last fork call the existing 4 process are made in to 8 and those former 4 process have pid of child as return value, and the new 4 process has the value 0. So should I change the provided code? Thanking you in advance.

Could you please run xsm with xsm --timer=2 (or timer =3) - basically small values. 

A better way is;  before return 0.  /* exit from process */  Put a while loop (say something like  i=1 to 500 do a=1;)  in each processes. 

The issue probability with your program is that the processes exit very quickly and hence the process table entries get free quickly.

Hence, by the time new processes are created, the same PID is given (because the process with the PID had already finished). 

When you put a large loop  within each process before they exit after the child is created, new new PID-s will have to be allocated for newly created process,

as the parent has not released the PID. 

As with some previous question raised here, if this doesn't fix the problem, then your OS code has some issues.

Murali

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