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);
Explain why SSTF scheduling tends to favor middle cylinders over the innermost and outermost cylinders. The center of the disk is the location having the fewest average distanc
what is file abstraction?
A file system depends on data structures about the files, beside the file structure. The former is named metadata-data that defines data. Each file is accumulated with an inode, wh
What is the resident set and working set of a process? Resident set is that portion of the process image that is actually in real-memory at a certain instant. Working set is th
Give an overview of UNIX based file systems. UNIX and UNIX-like operating systems allocate a device name to each device, other than this isn't how the files on that device are
The physical memory acts as a cache backed by the disk. When the physical memory is full, and we want to read in another page from disk, we have to evict a page from physical memor
What are conditions under which a deadlock situation may arise? A deadlock situation can arise if the following four conditions hold simultaneously in a system: a. Mutual ex
how fat file system is organised
what is unbounded buffer
Problem 1: (a) The grouping of organisational activities (usually into ‘departments' or larger ‘divisions') can be done in different ways. Outline 7 criteria which can be used
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