last os

Process Creation:

Processes are created with the fork system call.

So what is fork() ?

Producer Consumer code using semaphore:

video tutorial
semaphore S=1;
semaphore  E=n;
semaphore F=0;

void producer()
{
while (T)
{
 produce();
wait(E);
wait(S);
append();
signal(S);
signal (F);
}
}

void consumer()
{
while(T)
{
wait(F);
wait(S);
take();
signal(S);
signal (E);
use();
}
}

Reader writer problem : 

youtube tutorial 

Structure of writer process:

 while(true)

{

 wait(wrt);

 //writing is performed

 signal(wrt);

 

}

Structure of reader process: 

 while (true)

{

  wait(mutex);

  readcout++;

  if(readcount==1)

  {

  wait(wrt);

  } 

  signal(mutex);

 //reading is perform

 wait(mutex);

readcout--;

if(readcout==0)

signal(wet);

signal(mutex);

}

 

system call