OS UNIT 5 operation system memory management.pptx

Os

1. Unit 5 Memory Management

2. Partitioning A partitioning is a logical division on a hard disk drive that enables a PC to have different drives. A partition divides the hard drive into several logical storage units on one drive but functions as multiple drives. Partition can also be referred as slices.

3. Fixed Partition It is also known as static partitioning Size of each partition is same or may not be same. OS 4MB 8 MB 32 MB OS 8 MB 8 MB 8 MB

4. Variable Partitioning It is also known as dynamic partitioning. OS OS P1 2KB P2 8 MB P3 4 MB P4 8 MB

5. Advantages No chance of internal fragmentation. No limitation of number of processes No limitation on size of process

6. Free space management Techniques Bitmap Linked List

7. Bitmap P1 3KB 4 KB P3 2KB 1 1 1 1 1

8. Linked List OS P1 Hole P2 P3 Hole P1 99 99 300 200 440 500 H 99 200 P2 200 300 P3 300 440 H 440 500