2. - means "replacement of a block of stored instructions or data with another.“ - a method that allows programs to be larger than the computer's main memory

3. INCLUDE SYSLIB (MOD1) INCLUDE SYSLIB (MOD2) OVERLAY A INCLUDE SYSLIB(MOD3) INCLUDE SYSLIB(MOD4) INCLUDE SYSLIB(MOD5) INCLUDE SYSLIB(MOD6) INCLUDE SYSLIB(MOD7) Root Segment MOD1, MOD2 OVERLAY A INCLUDE SYSLIB(MOD3) INCLUDE SYSLIB(MOD4) INCLUDE SYSLIB(MOD5) INCLUDE SYSLIB(MOD6) INCLUDE SYSLIB(MOD7)

4. INCLUDE SYSLIB (MOD1) INCLUDE SYSLIB (MOD2) OVERLAY A INCLUDE SYSLIB(MOD3) OVERLAY AA INCLUDE SYSLIB(MOD4) INCLUDE SYSLIB(MOD5) OVERLAY AB INCLUDE SYSLIB(MOD6) OVERLAY B INCLUDE SYSLIB(MOD7) Root Segment MOD1, MOD2 Overlay A MOD3 Overlay B MOD7 Overlay AA MOD3 Overlay AB MOD7

5.  a simple memory management policy  moving of a complete / entire process IN or OUT of memory processes between main memory and secondary. Data can be moved includes:  process blocks (pcb)  data variables (i.e. heap, stack)  codes / program instructions (in machine language)  etc…

6. OS Process 2 Process 5 Process 1 (40 KB) Process 6 Process 7 (15 KB) Process 3 Process 8 (20 KB) Swap Space Files Swap OUT Swap IN Main MemorySecondary Memory

7.  Memory compaction is the process of moving allocated objects together, and leaving empty space together  also known as “burping the memory” so that huge processes can fit into memory  merging vacant holes into one

8. P1 = 200kb P2 = 100kb P4 = 200kb P6 = 400kb P3 = 400kb P5 = 300kb P7 = 200kb Free = 400kb Free = 300kb Free = 200kb P1 = 200kb P2 = 100kb P4 = 200kb P6 = 400kb Free = 900kb P1 = 200kb P2 = 100kb P4 = 200kb P6 = 400kb Free = 900kb New Process MR = 700kb

9.  accommodates jobs into memory only when the process fit in any of the fixed sized partitions. Internal Fragmentations – is the amount of unused memory space within a partition produced when a small process is allocated to a big partition. External Fragmentations – the amount of memory regions that are available but are too small to accommodate any incoming process.

10.  First Fit – allocation always starts at the beginning of the memory.  Best Fit – allocates an incoming job to the smallest available partition  Next Fit – modified version of FF. Starts from the beginning of the memory and allocates the job to the first hole that it finds capable of accepting the job.  Worst Fit – works in opposite manner when compared to BF. It allocates the largest hole to a particular program / process.

11.  in this approach, user space is deemed as one big hole in the memory before the start of process allocation.  temporary partitions are created when jobs are placed inside the memory and this partitions are erased when jobs leaves the user space