Already have an account? Get multiple benefits of using own account!
Login in your account..!
Remember me
Don't have an account? Create your account in less than a minutes,
Forgot password? how can I recover my password now!
Enter right registered email to receive password!
Write a note on semaphores
A semaphore is a tool meant for synchronizing multiple processes trying to access a shared variable. That is a semaphore is used to deal with the critical section problem or in other words to evade the race condition. A semaphore S is in fact an integer variable that apart from initialization is accessed only through two standard atomic operations:
*Wait and signal.
The traditional definition of wait in pseudo code is:
wait (S) {
while (S<=0)
; // no-op
S--;
}
The traditional definition of signal in pseudo code is:
signal (S) {
S++;
For each process P,
do {
WAIT
Critical Section
SIGNALS
} while (1);
A semaphore is able to be defined as:
typedef struct {
int value;
struct process *L;
} semphore;
Once more, the wait semaphore operation can be defined as:
void wait (semaphore S) {
S.value--;
if (S.value < 0) {
add this process to S.L;
block();
As well, the signal semaphore operation is able to be defined as:
void signal( semaphore S) {
S.value++;
if (S.value <= 0) {
remove a process P from S.L;
wakeup(P);
Under what circumstances do page faults occur? Describe the actions taken by the operating system when a page fault occurs. A page fault happens when an access to a page that
Q. Consider a distributed system with two sites A and B. Consider whether site A can distinguish among the following: a. B goes down. b. The link between A and B goes down.
Q. List the four steps that are essential to run a program on a completely dedicated machine. Answer: a) Reserve machine time b) Manually load program into memory c)
What factors are involved in choosing the host operating system?
What is linked allocation, as detailed in text? Directory has pointers to first and last blocks of file. Every block of file (except last) has pointer to the next block.
Define the Server Communications Module or SCM The Server Communications Module (SCM) performs many necessary functions. The SCM responsible for establishing, maintaining, and
Q. Is disk scheduling except FCFS scheduling useful in a single-user environment? describe your answer. Answer: In a single-user environment the I/O queue typically is empty.
Define the properties operating systems: Batch :- Jobs with similar needs are batched together and run through the computer as a group by an operator or automatic job sequenc
what is inter process communication..
Describe the file system architecture. File System Architecture contains the subsequent components:- Device Driver 1 Device Driver 2 Device Driver 3 Basic fi
Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!
whatsapp: +91-977-207-8620
Phone: +91-977-207-8620
Email: [email protected]
All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd