Operating Systems Chapter 4: Memory Management E 4.1 Basic memory management 4.2 Swapping(交换) 43 irtual memory(虚拟内存) H 4.4 Page replacement algorithms H 4.5 Design issues for paging systems E 4.6 Implementation issues 47 Segmentation(分段) Gao Haichang, Software School, Xidian University 3
Operating Systems Gao Haichang , Software School, Xidian University 3 Chapter 4: Memory Management 4.1 Basic memory management 4.2 Swapping (交换） 4.3 Virtual memory （虚拟内存） 4.4 Page replacement algorithms 4.5 Design issues for paging systems 4.6 Implementation issues 4.7 Segmentation （分段）
Operating Systems Memory Management c Ideally programmers want memory that is A large t fast 口 non volatile Memory hierarchy(层次) H small amount of fast, expensive memory -cache E some medium-speed medium price main memory H gigabytes ofslow, cheap disk storage G Memory manager handles the memory hierarchy Gao Haichang, Software School, Xidian University
Operating Systems Gao Haichang , Software School, Xidian University 4 Memory Management Ideally programmers want memory that is large fast non volatile Memory hierarchy （层次） small amount of fast, expensive memory – cache some medium-speed, medium price main memory gigabytes of slow, cheap disk storage Memory manager handles the memory hierarchy
Operating Systems Basic memory management G Memory Management Systems can be divided into two classes: H That move processes back and forth between main memory and disk during execution(swapping and paging) That do not ce Program expand to fill the memory available to hold them Gao Haichang, Software School, Xidian University
Operating Systems Gao Haichang , Software School, Xidian University 5 Basic Memory Management Memory Management Systems can be divided into two classes: That move processes back and forth between main memory and disk during execution (swapping and paging). That do not. Program expand to fill the memory available to hold them
Operating Systems Gs Monoprogramming without Swapping or Paging OXFFF Operating Device system in drivers in ROm ROM ser program ser User program Operating Operating system in system in RAM RAM Three simple ways of organizing memory an operating system with one user process (a) formally used on mainframes and minicomputers but is really used any more (b)used on some palmtop computers and embedded systems (c)used by early PC(MS-DOS), where the portion of the system in the ROM is called the bios Gao Haichang, Software School, Xidian University
Operating Systems Gao Haichang , Software School, Xidian University 6 Monoprogramming without Swapping or Paging Three simple ways of organizing memory - an operating system with one user process - (a) Formally used on mainframes and minicomputers but is really used any more. - (b) used on some palmtop computers and embedded systems. - (c) used by early PC (MS-DOS), where the portion of the system in the ROM is called the BIOS
Operating Sy Multiprogramming with Fixed Partitions Multiple input queues H口 Partition 44 Partition 4 Partition 3 Single Partition 3 input queue H Partition 2 Partition 2 200K Partition 1 100K erating gratin stem Fixed memory partitions H separate input queues for each partition H single input queue Gao Haichang, Software School, Xidian University
Operating Systems Gao Haichang , Software School, Xidian University 7 Multiprogramming with Fixed Partitions Fixed memory partitions separate input queues for each partition single input queue