Operating System (CS604) Assignment # 02

Operating System (CS604)

Assignment # 02

Fall 2020

Total marks = 20                                                       

Question No. 1                                                                                                                         12 Marks      

Considering the two processes SP (Server Process) and CP Client Process, each creates two child process sc1, sc2, and cc1, cc2, respectively.  These processes create two FIFOs, FIFO 1 for reading and FIFO 2 for writing in SP and FIFO 1 for writing and FIFO2 for reading in CP to communicate with each other as shown in the figure.

 

Figure 1. Client-Server Communication

By considering the above scenario, you are required to write the output of the following code snippets.

1. if ((mknod (FIFO1, S_IFIFO | PERMS, 0) < 0) && (errno != EEXIST))

 {

 perror ("mknod FIFO1");

 exit (1);

 }

2. if (mkfifo(FIFO2, PERMS) < 0) 

{

 unlink (FIFO1);

 perror("mknod FIFO2");

 exit (1);

3. if ((readfd = open(FIFO1, 0)) < 0)

 {

 perror ("open FIFO1");

 exit (1);

4. if ((writefd = open(FIFO2, 1)) < 0) 

{

 perror ("open FIFO2");

 exit (1);

5. size = strlen(MESSAGE1) + 1;

 if ((n = read(readfd, buff, size)) < 0) {

 perror ("server read"); exit (1);

 }

6. size = strlen(MESSAGE1) + 1;

 if (write(writefd, MESSAGE1, size) != size) 

{ perror ("client write1"); exit (1);  }

Question No. 2                                                                                                                         08 Marks      

Consider the following set of processes, with the Arrival time and CPU burst time, is given in milliseconds:

Process Arrival Time Burst Time 

P1 0.0 10

P2 2.0 6

P3 3.0 2

Considering the time slice of 4 milliseconds. 

A. Draw a Gantt chart showing the execution of these processes using the Shortest Remaining Time First (SRTF) scheduling.

B. Calculate the turnaround time of each process for the Shortest Remaining Time First scheduling algorithm as per part Calculation of part A?  

C. Calculate the waiting time of each process for the SRTF scheduling algorithm as per the calculation of Part A?