URGENT Help required regarding the use of FORK system call Post: 8103

Sponsored Content

Top Forums UNIX for Advanced & Expert Users URGENT Help required regarding the use of FORK system call Post 8103 by kkumar1975 on Friday 5th of October 2001 01:41:36 PM

10-05-2001

Registered User

URGENT Help required regarding the use of FORK system call

I desperately wanted one of the UNIX Gurus to help me resolve my problem asap(I have to deliver the code to the client by Monday 08-oct).

I have a file with around 5 million records (50 lakhs). Now my original process was taking around 30 hours to read the complete file, process each and every record and write it to another file. we do a lot of calculations for each and every record so it takes that time.

Now I planned to implement PARALLEL processing in my program. So I am dividing the complete input file into 5 chunks (each of 1 million) and sending every chunk to every child process to process. Now every child process will process its own chunk and write it to its own temporary file. Finally in the parent process I am planning to merge all the temporary files together. By doing this I believe I shall save a lot of processing time.

What I am basically interested to know is that what are the side effects of using FORK in the C programs? Are there any SYSTEM level impacts by using FORK? Is there any system call to merge multiple files into ONE? I am interested in knowing what happens if a Child is killed? How can I reprocess the child that is killed? How do I ensure that there are no ZOMBIES or INFANT process created?

Can some one briefly advise how I can proceed with my Logic. I have already written the logic but I want to cross check if there is something I am missing in my logic.

Thanks,
Kumar

kkumar1975

View Public Profile for kkumar1975

Find all posts by kkumar1975

10 More Discussions You Might Find Interesting

1. Programming

Need urgent help with fork()

Hy! I must wrote some code with fork() command. The thing is that i have a while statement which count till 10. I must wrote a program that one child has only one parent. So one parent has only one child and one child has only one parent. Can you please help me with these code. int main()...

2. Programming

Fork() system call time?

One more question. How can i calculate the time that system needs to make fork() system call? I need to make it with times function but i really don't know how. :(

3. UNIX for Dummies Questions & Answers

fork() system call

Can anyone explain me what really happens when a system call fork() is called ? I like to know what happens internally. Thanks in Advance. - Arun

4. Programming

Help required with using system() call

Hi, I try to write a C program which lists the output of a paticular command with all the available options (a to z) for the command in the directory of execution. This program will generate the output if the option exists for the particular command else it will display some message saying...

5. UNIX for Dummies Questions & Answers

fork system call

Hi folks, I want to know how this below program works? #include <stdio.h> int main() { printf("A\n"); fork(); printf("B\n"); fork(); fork(); printf("D\n"); fork(); printf("C\n"); } This is just for example. How this type of programs where fork is used many places, how the...

6. Homework & Coursework Questions

fork system call understanding

Use and complete the template provided. The entire template must be completed. If you don't, your post may be deleted! 1. The problem statement, all variables and given/known data: i have a problem in understanding the behaviour of fork . i understood fork as to create a new process and...

7. Shell Programming and Scripting

fork system call and \n

hi, i tried the following source codes: fork1.c: main() { printf("demo of fork\n"); fork(); printf("hello"); } output: demo of fork hello hello fork2.c: main() { printf("demo of fork");

8. Programming

Problem with execution of fork system call if i use \n

hi all, i tried the following source codes: fork1.c: main() { printf("demo of fork\n"); fork(); printf("hello"); } output: demo of fork hello hello fork2.c: main()

9. UNIX for Advanced & Expert Users

Doubt with fork() system call

Hi I wrote a simple fork program to illustrate the fork() system cal. here it is #include<stdio.h> #include<sys/stat.h> #include<sys/types.h> main() { int flag; flag=fork(); if(flag==0) { printf("Child \n"); printf("Process id= %d\n",getpid()); ...

10. Shell Programming and Scripting

Help: how to call fork() in shell script? New to linux

Hi, I'm writing a shell script where I want to call fork(). However I wrote like this "var=fork()" in c style and got this error: "syntax error near unexpected token `(' " How could I call fork() in shell script? Thanks in advance. Duplicate Post - Continue Here - Please Do Not Cross Post...

LEARN ABOUT V7

fork

FORK(2) 							System Calls Manual							   FORK(2)

NAME

       fork  -	spawn new process

SYNOPSIS

       fork( )

DESCRIPTION

       Fork  is  the only way new processes are created.  The new process's core image is a copy of that of the caller of fork.  The only distinc-
       tion is the fact that the value returned in the old (parent) process contains the process ID of the new (child) process,  while	the  value
       returned in the child is 0.  Process ID's range from 1 to 30,000.  This process ID is used by wait(2).

       Files open before the fork are shared, and have a common read-write pointer.  In particular, this is the way that standard input and output
       files are passed and also how pipes are set up.

SEE ALSO

       wait(2), exec(2)

DIAGNOSTICS

       Returns -1 and fails to create a process if: there is inadequate swap space, the user is not super-user and has too many processes, or  the
       system's process table is full.	Only the super-user can take the last process-table slot.

ASSEMBLER

       (fork = 2.)
       sys fork
       (new process return)
       (old process return, new process ID in r0)

       The return locations in the old and new process differ by one word.  The C-bit is set in the old process if a new process could not be cre-
       ated.

																	   FORK(2)