MODERN OPERATING SYSTEMS Third edition ANDREW S TANENBAUM Chapter 3 Memory Management Tanenbaum, Modern Operating Systems 3 e, (c)2008 Prentice-Hall, Inc. All rights reserved. 0-13-6006639
MODERN OPERATING SYSTEMS Third Edition ANDREW S. TANENBAUM Chapter 3 Memory Management Tanenbaum, Modern Operating Systems 3 e, (c) 2008 Prentice-Hall, Inc. All rights reserved. 0-13-6006639
Memory management Memory(RAM)is an important and rare resource a Programs expand to fill the memory available to them Programmer's view a Memory should be private, infinitely large, infinitely fast, nonvolatile Reality a Best of people's mind: memory hierarchy a Register, cache, memory, disk, tape Memory manager a Efficiently manage memory a Keep track the free memory, allocate memory to programs
Memory Management ◼ Memory (RAM) is an important and rare resource ❑ Programs expand to fill the memory available to them ◼ Programmer’s view ❑ Memory should be private, infinitely large, infinitely fast, nonvolatile… ◼ Reality ❑ Best of people’s mind: memory hierarchy ❑ Register, cache, memory, disk, tape ◼ Memory manager ❑ Efficiently manage memory ❑ Keep track the free memory, allocate memory to programs…
Memory management The memory management in this chapter ranges from very simple to highly sophisticated
Memory management ◼ The memory management in this chapter ranges from very simple to highly sophisticated…
No Memory abstraction Early mainframe, early minicomputers, early personal computers had no memory abstraction 口 MOV REG|STER1.1000 a Here 1000 means move the content of physical memory address 1000 to register Impossible to have two programs in memory
No Memory Abstraction ◼ Early mainframe, early minicomputers, early personal computers had no memory abstraction… ❑ MOV REGISTER1, 1000 ❑ Here 1000 means move the content of physical memory address1000 to register ◼ Impossible to have two programs in memory
No Memory abstraction OXFFF Operatin Device system in drivers in rOm ROM User program program User program Operating Operating system in system in RAM RAM 0 0 0 (b) Figure 3-1. Three simple ways of organizing memory with an operating system and one user process Tanenbaum, Modern Operating Systems 3 e, (c)2008 Prentice-Hall, Inc. All rights reserved. 0-13-6006639
Figure 3-1. Three simple ways of organizing memory with an operating system and one user process. No Memory Abstraction Tanenbaum, Modern Operating Systems 3 e, (c) 2008 Prentice-Hall, Inc. All rights reserved. 0-13-6006639