unix test 2 review

Question 1

The ____ contains all the information about the file: the file type, the file’s access permission bits, the size of the file, pointers to the file’s data blocks, and so on.

Answer 1

i- node

Question 2

By convention, all shells in Unix open ___ file descriptors whenever a new program is run.

Answer 2

3

Question 3

A process may do \_\_\_ with the signal
ignore the signal
let the default action occur
provide a function to handle the signal
all of the above

Answer 3

All of the above

Question 4

Including the initial parent process, the total number of the processes (in total) will be ____ after executing the code segment below.
if (pid=fork()) {fork();}
if (pid=fork()) {fork();}
if (pid=fork()) {fork();}

Answer 4

27

Question 5

A ___ has only one thread of control - one set of machine instructions executing at a time.

Answer 5

process

Question 6

After fork, the differences between the parent and child are:
The return values from fork
The process IDs
The different parent process IDs
 Correct 
All of the above

Answer 6

All of the above

Question 7

Including the initial parent process, the total number of the processes (in total) will be ____ after executing the code segment below.
if (pid=fork() && pid2 = fork()) {fork();}
if (pid=fork() && pid2 = fork()) {fork();}
if (pid=fork() && pid2 = fork()) {fork();}

Answer 7

64

Question 8

A file ___ is normally small non-negative integer that the kernel uses to identify the files accessed by a process.

Answer 8

descriptor

Question 9

Given fork program as shown below, what would be the total number of processes at the end including the process running this program initially.

for (i=1; i

Answer 9

4

Question 10

By convention, UNIX System shells associate the file descriptor __ with the standard input of a process.

Answer 10

0

Question 11

This instruction ___ takes two (file descriptor) arguments, to duplicate the first one (file descriptor) to be set for the second one.

Answer 11

dup2

Question 12

___ will make a copy of the current process.

Answer 12

fork

Question 13

___ is a type of file that points to another file.

Answer 13

symbolic link

Question 14

Consider a code segment for a pipe (e.g., to run “ls | wc”) as we discussed in the classes, shown below.
What would it be the code segment using execlp for the “parent” process after setting the file descriptors for the pipe?

Answer 14

execlp(“ls”,”ls”,(char *)0);

Question 15

The new file descriptor returned by dup is guaranteed to be the ___ numbered available file descriptor

Answer 15

lowest

Question 16

Given fork program as shown below, what would be the total number of processes at the end including the process running this program initially.
for (i=1; i

Answer 16

1

Question 17

Including the initial parent process, the total number of the processes (in total) will be ____ after executing the code segment below.

if (fork()

Answer 17

2

Question 18

When a process calls one of the ____ functions, that process is completely replaced by the new program, and the new program starts executing at its main function. It merely replaces the current process its text, data, heap, and stack segments with a brand-new program from disk.

Answer 18

exec

Question 19

Including the initial parent process, the total number of the processes (in total) will be ____ after executing the code segment below.

if (pid=fork()) {fork();}
if (pid=fork()) {fork();}
if (pid=fork()) {fork();}

Answer 19

27

Question 20

Including the initial parent process, the total number of the processes (in total) will be ____ after executing the code segment below.

if fork() fork(

Answer 20

3

Question 21

The new process created by fork is called the child process. This function is called once but returns ___.

Answer 21

twice

Question 22

Consider a code segment for a pipe (e.g., to run “ls | wc”) as we discussed in the classes, shown below.

What would it be the code segment for the “parent” process after fork but before exec?

Answer 22

close(pfd[0]); dup2(pfd[1], 1); close(pfd[1]);

Question 23

What would be a proper way to set a signal handler (sig_int) for SIGINT?

Answer 23

signal(SIGINT,sig_int);

Question 24

Including the initial parent process, the total number of the processes (in total) will be ____ after executing the code segment below.

fork(); fork(); fork();

Answer 24

8

Question 25

A process is

Answer 25

a program which is started but not terminated

Question 26

After fork, the return value for the child is ___

Answer 26

0

Question 27

After fork, the return value for the parent process is ___

Answer 27

the child process id

Question 28

Signals provide a way of handling ___ events

Answer 28

asynchronous