Fork() is a system call USED for creating child processes of a parent PROCESS.it returns the process id of the created child process.after that pid(process id ) is checked if it is negative,it means no child process is created,pid==0 IMPLIES the id of the NEWLY created process and pid>0 is the id of child process given to the parent process.the statements following fork system call are executed by both the parent and child process.and one more thing,the parent and child process have the exact copy of address space but it exist SEPARATELY for the two processes.

Fork() is a system call used for creating child processes of a parent process.it returns the process id of the created child process.after that pid(process id ) is checked if it is negative,it means no child process is created,pid==0 implies the id of the newly created process and pid>0 is the id of child process given to the parent process.the statements following fork system call are executed by both the parent and child process.and one more thing,the parent and child process have the exact copy of address space but it exist separately for the two processes.