tailieunhanh - Lecture Operating systems: A concept-based approach: Chapter 11 - Dhananjay M. Dhamdhere

This chapter is devoted to the fundamentals of memory management. It begins by discussing how memory protection is implemented in the hardware by using special registers in the CPU. It then discusses how efficient use of memory is achieved by reusing memory released by a process while handling subsequent memory requests, and how techniques for fast memory allocation and deallocation may cause memory fragmentation. | Chapter 11 Memory Management Copyright © 2008 Operating Systems, by Dhananjay Dhamdhere Introduction Managing the Memory Hierarchy Static and Dynamic Memory Allocation Execution of Programs Memory Allocation to a Process Heap Management Contiguous Memory Allocation 11. Operating Systems, by Dhananjay Dhamdhere Copyright © 2008 Operating Systems, by Dhananjay Dhamdhere Introduction (continued) Noncontiguous Memory Allocation Paging Segmentation Segmentation with Paging Kernel Memory Allocation Using Idle RAM Effectively 11. Operating Systems, by Dhananjay Dhamdhere Copyright © 2008 Operating Systems, by Dhananjay Dhamdhere Managing the Memory Hierarchy 11. Operating Systems, by Dhananjay Dhamdhere Copyright © 2008 Operating Systems, by Dhananjay Dhamdhere Static and Dynamic Memory Allocation Memory allocation is an aspect of a more general action in software operation known as binding Static allocation performed by compiler, linker, or loader Sizes of data . | Chapter 11 Memory Management Copyright © 2008 Operating Systems, by Dhananjay Dhamdhere Introduction Managing the Memory Hierarchy Static and Dynamic Memory Allocation Execution of Programs Memory Allocation to a Process Heap Management Contiguous Memory Allocation 11. Operating Systems, by Dhananjay Dhamdhere Copyright © 2008 Operating Systems, by Dhananjay Dhamdhere Introduction (continued) Noncontiguous Memory Allocation Paging Segmentation Segmentation with Paging Kernel Memory Allocation Using Idle RAM Effectively 11. Operating Systems, by Dhananjay Dhamdhere Copyright © 2008 Operating Systems, by Dhananjay Dhamdhere Managing the Memory Hierarchy 11. Operating Systems, by Dhananjay Dhamdhere Copyright © 2008 Operating Systems, by Dhananjay Dhamdhere Static and Dynamic Memory Allocation Memory allocation is an aspect of a more general action in software operation known as binding Static allocation performed by compiler, linker, or loader Sizes of data structures must be known a priori Dynamic allocation provides flexibility Memory allocation actions constitute an overhead during operation 11. Operating Systems, by Dhananjay Dhamdhere Copyright © 2008 Operating Systems, by Dhananjay Dhamdhere Execution of Programs A has to be transformed before it can be executed Many of these transformations perform memory bindings Accordingly, an address is called compiled address, linked address, etc 11. Operating Systems, by Dhananjay Dhamdhere Copyright © 2008 Operating Systems, by Dhananjay Dhamdhere A Simple Assembly Language Format of an assembly language statement: [Label] , First operand is always a GPR AREG, BREG, CREG or DREG Second operand is a GPR or a symbolic name that corresponds to a memory byte Opcodes are self-explanatory ADD, MULT, MOVER, MOVEM, BC For simplicity, assume that addresses and constants are in decimal, and instructions occupy 4 bytes 11. Operating Systems, by .