PROCESS SCHEDULING AND MEMORY MANAGEMENT

1. M. DHARANI M.SC(CS),
NADAR SARASWATHI COLLEGE
OF ARTS AND SCIENCE,
THENI.
PROCESS SCHUDELING &
MEMORY MANAGEMENT

2. DEFINITION
Process management is an integral
part of any modern day operation
system. The OS must allocate
resources to processes, enable
processes to share and exchange
information, protect the resources
of each process from other
processes and enable synchronization
among processes.

3. To meet these requirements the
OS must maintain a data
structure for each process,
which describes the state and
resource ownership of that
process and which enables the
OS to exert control over each
process.

4. A process goes through a series of discrete
process states. Various events can cause a
process to change states:
Submit state
Hold state
Ready state
Running state
Wait state
Complete state

5. Process scheduling is one of the most important
functions of an operating system that supports
multiprogramming. This function is heavily
dependent on queues. There are three types of
queues that are used in process scheduling:
Job Queue
Ready Queue
Device Queue

6. Job Queue:
Contains all processes that have been
introduced into the system.
Ready Queue:
Contains processes that are waiting for CPU
time, and can be selected to run at any time.
Device Queue:
Contains processes waiting on a certain
device. Each device has its own queue for
processes that need I/O from it.

7. DIFFERENT ALGORITHMS USED FOR
HANDLING PROCESSES
Deterministic Scheduling:
An algorithm where in all characteristics of
a process are known in advance or before
execution.
Non-Deterministic Scheduling:
An algorithm where in characteristics of
processes are not known in advance.

8. TYPES OF QUEUE BEING USED
Single Queuing:
All process arrives at the same time with
their corresponding burst time.
Multiple Queuing:
Each process has its won arrival time in the
processor.

9. PROCESS SCHEDULING
Good policies to schedule processes:
1. Maximum Throughput
2. Minimize Response Time
3. Minimize Turnaround time
4. Minimize Waiting time
5. Maximize CPU Efficiency
6. Ensure fairness for All Jobs

10. PROCESS SCHEDULING ALGORITHM
Here, are six commonly used process scheduling
algorithms,
1. First come, First Served (FCFS)
2. Shortest job Next (SJN)
3. Priority Scheduling
4. Shortest Remaining Time (SRT)
5. Round Robin
6. Multi-Level Queues

11. DEAD LOCK
Dead lock can be said to occur when a process is
allocated some non-sharable resources but is
forced to wait for other non-sharable resources.
program proc A;
begin
open (File);
Do more stuff;
open (File2);
Do stuff;
End

12. PROGRAM Proc A:
BEGIN
Do stuff;
Open (file1);
Do more stuff;
Open(File 2);
Do stuff;
END
PROGRAM PROC B:
BEGIN
Do stuff;
Open (File 2);
Do more stuff;
Open (File 1);
Do stuff;
END

13. PROCESS A
FILE 1
FILE 2

14. SEVEN TYPES OF DEADLOCK
Deadlock on file requests
Deadlock in databases
Deadlock in dedicated device allocation
Deadlock in multiple device allocation
Deadlock in spooling
Deadlock in a network
Deadlock in disk sharing

15. THANK YOU !!!