Unix IPC Interview Preparation Guide Download PDF
Unix IPC frequently Asked Questions in various Unix Inter-Process Communication (IPC) job Interviews by interviewer. The set of Unix IPC interview questions here ensures that you offer a perfect answer to the interview questions posed to you. Get preparation of Unix IPC job interview
26 Unix Inter-Process Communication (IPC) Questions and Answers:
1 :: How to get or set an environment variable from a program?
to get environment variable execute getenv();
to set environment variable execute setenv();
to set environment variable execute setenv();
2 :: What are the system calls used for process management?
This should not allow to increase process priority.
3 :: Predict the output of the following program code
main()
{
fork();
printf("Hello World!");
}
prints Hello world Hello world
All the statements after the call to fork() will be
executed twice
All the statements after the call to fork() will be
executed twice
4 :: Please Explain fork() system call?
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.
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.
5 :: What are various IDs associated with a process?
Real User id, Effective User Id, saved user id.
Real Group id, Effective Group Id, saved Group id.
Real Group id, Effective Group Id, saved Group id.
6 :: Explain the initial process sequence while the system
boots up?
While booting, special process called the 'swapper'
or 'scheduler' is created by the Process-ID 0. The swapper
manages memory allocation for processes and influences CPU
allocation. The swapper in turn creates 3 children: the
process dispatcher, vhand, etc...
or 'scheduler' is created by the Process-ID 0. The swapper
manages memory allocation for processes and influences CPU
allocation. The swapper in turn creates 3 children: the
process dispatcher, vhand, etc...
7 :: Tell me set-user-id is related to (in unix)?
setuid short for set user ID upon execution is Unix access
rights flag that allow users to run an executable with the
permissions of the executable's owner. This is often used to
allow users on a computer system to run programs with
temporarily elevated privileges in order to perform a
specific task. While the assumed user id privileges provided
are not always elevated, at a minimum that is specific.
setuid and setgid are needed for tasks that require higher
privileges than those which a common user has, such as
changing his or her login password. Some of the tasks that
require elevated privileges may not immediately be obvious,
though — such as the ping command, which must send and
listen for control packets on a network interface.
rights flag that allow users to run an executable with the
permissions of the executable's owner. This is often used to
allow users on a computer system to run programs with
temporarily elevated privileges in order to perform a
specific task. While the assumed user id privileges provided
are not always elevated, at a minimum that is specific.
setuid and setgid are needed for tasks that require higher
privileges than those which a common user has, such as
changing his or her login password. Some of the tasks that
require elevated privileges may not immediately be obvious,
though — such as the ping command, which must send and
listen for control packets on a network interface.
8 :: What is the condition required for dead lock in Unix system?
deadlock occurs because of
1.no preembtion
2.circular waiting i.e.. when A process is waiting for the
resources which are held by the procees B,which is waiting
for the resources engaged by process A.
1.no preembtion
2.circular waiting i.e.. when A process is waiting for the
resources which are held by the procees B,which is waiting
for the resources engaged by process A.
9 :: What is i-node numbers?
File is identified by the I-node number in linux.Kernel uses
inode number to access the file. It is unique for the
perticular filesystem. Inode contains all the information
about the file like , file size, access permissions, time
stamp , uid , gid , pointers to data blocks..etc.
inode number to access the file. It is unique for the
perticular filesystem. Inode contains all the information
about the file like , file size, access permissions, time
stamp , uid , gid , pointers to data blocks..etc.