Week 4 - Processes and Low Level I/O

Question 1

What library is syscall in?

Answer 1

unistd.h

Question 2

What library is fopen in?

Answer 2

stdio.h

Question 3

What library is fork in?

Answer 3

unistd.h

Question 4

What library is exit in?

Answer 4

stdlib.h

Question 5

What library is printf in?

Answer 5

stdio.h

Question 6

What library is get_pid in?

Answer 6

unistd.h

Question 7

What library is sleep in?

Answer 7

unistd.h

Question 8

What library is wait in?

Answer 8

sys/wait.h

Question 9

What is SYSNO?

Answer 9

the system call number

Question 10

How do you make a direct syscall?

Answer 10

long int syscall( long int SYSNO, …)

Question 11

How do you create a new child?

Answer 11

pid_t fork();

Question 12

What number is the standard input?

Answer 12

0

Question 13

What number is the standard output?

Answer 13

1

Question 14

What number is the standard error?

Answer 14

2

Question 15

How does the parent wait for the child to terminate?

Answer 15

pid_t wait(int *status);

Question 16

How do you suspend a process?

Answer 16

unsigned in sleep( unsigned int secs);

Question 17

What are the steps to opening a file?

Answer 17

• kernel checks you have the right
• kernel returns the file descriptor
• kernel keeps track of open file info

Question 18

How do you open a file?

Answer 18

FILE *fopen( char *name, char *mode);

Question 19

What does a file handler contain?

Answer 19

• pointer to a buffer
• number of characters left in the buffer
• pointer to next position in the buffer
• the file descriptor
• various flags