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);
What are the typical elements of a process image? User data: Modifiable part of user space. May have program data, user stack area, and programs that might be modified. User
Define System Call A system call is a request that is made by any program to the operating system for carrying out tasks - picked from a predefined set - which the said program
Q. Distinguish among PCS and SCS scheduling. Answer: PCS scheduling is completed local to the process. It is how a thread library schedules threads onto available LWPs. SCS sch
Questiion 1 Use Priority Scheduling Algorithm to schedule the following processes Process Burst Time Priority/Time P1
Additional-reference-bits algorithm We can keep an 8-bit byte for every page in a table in memory. The operating system shifts the reference bits right 1 bit, discarding the lo
What are the different file operations? Create : - Space for the file in the file system update directory table. Write : - file name and data to be written is
Write a program (with the programming language and on the platform of your choice) to demonstrate the memory leak problem (see http://en.wikipedia.org/wiki/Memory_leak for detail
Describe paging technique used in UNIX systems. When a process begin in UNIX, not every its memory pages are read in from the disk at once. In its place, the kernel loads into
what are the objective of operating system assignment
Explain about paging? Answer: Paging is a memory-management scheme that permits the physical-address space of process to be noncontiguous. Paging avoids the considerable proble
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