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Lecture Operating systems: Internals and design principles (6/E): Chapter 7 - William Stallings

Chapter 7 - Memory management. After studying this chapter, you should be able to: Discuss the principal requirements for memory management, understand the reason for memory partitioning and explain the various techniques that are used, understand and explain the concept of paging,. | Chapter 7 Memory Management Operating Systems: Internals and Design Principles, 6/E William Stallings Patricia Roy Manatee Community College, Venice, FL ©2008, Prentice Hall These slides are intended to help a teacher develop a presentation. This powerpoint covers the entire chapter and includes too many slides for a single delivery. Professors are encouraged to adapt this presentation in ways which are best suited for their students and environment. 1 Roadmap Basic requirements of Memory Management Memory Partitioning Basic blocks of memory management Paging Segmentation Overview of points covered in this chapter Point out that memory partitioning isn’t used much except for special cases such as kernel memory management 2 The need for memory management Memory is cheap today, and getting cheaper But applications are demanding more and more memory, there is never enough! Memory Management, involves swapping blocks of data from secondary storage. Memory I/O is slow compared to a CPU . | Chapter 7 Memory Management Operating Systems: Internals and Design Principles, 6/E William Stallings Patricia Roy Manatee Community College, Venice, FL ©2008, Prentice Hall These slides are intended to help a teacher develop a presentation. This powerpoint covers the entire chapter and includes too many slides for a single delivery. Professors are encouraged to adapt this presentation in ways which are best suited for their students and environment. 1 Roadmap Basic requirements of Memory Management Memory Partitioning Basic blocks of memory management Paging Segmentation Overview of points covered in this chapter Point out that memory partitioning isn’t used much except for special cases such as kernel memory management 2 The need for memory management Memory is cheap today, and getting cheaper But applications are demanding more and more memory, there is never enough! Memory Management, involves swapping blocks of data from secondary storage. Memory I/O is slow compared to a CPU The OS must cleverly time the swapping to maximise the CPU’s efficiency Introduce by pointing out that in a uniprogramming system, main memory is divided into two parts: one part for the operating system (resident monitor, kernel) and one part for the program currently being executed. In a multiprogramming system, the “user” part of memory must be further subdivided to accommodate multiple processes. Emphasise that memory management is vital in a multiprogramming system. If only a few processes are in memory, then for much of the time all of the processes will be waiting for I/O and the processor will be idle. Thus memory needs to be allocated to ensure a reasonable supply of ready processes to consume available processor time. 3 Memory Management Memory needs to be allocated to ensure a reasonable supply of ready processes to consume available processor time 4 Memory Management Requirements Relocation Protection Sharing Logical organisation Physical organisation The following slides .