操作系統(tǒng)原理緒論(英文課件)-在線瀏覽
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【正文】 nagement(913) Mainly deal with: ? Memory management ? Virtual memory ? File systems ? I/O systems ? Massstorage structure Protection and security(1819) Mainly cover: ? Protection ? Security Chapter 1: Introduction ? What is an Operating System? ? History of Operating Systems ? The Operating System Zoo What is an Operating System? There are a lot of definitions. Do you know? Definition from Wikipedia An operating system (OS) is an interface between hardware and applications。s workflow so as to make the puter system convenient for users to use reasonably and efficiently. 控制和管理計(jì)算機(jī)軟硬件資源，合理組織計(jì)算機(jī)工作流程，方便用戶合理使用計(jì)算機(jī)的程序的集合。), and consumed 150 kW of power. ? Input was possible from an IBM card reader, and an IBM card punch was used for output. ? No programming language, let alone OS Punched Card A Famous Remark ! I think there is a world market for maybe five puters. Thomas Watson, chairman of IBM, 1943 Second Generation 1955 – 1965 ? Universities started to buy puters (spending millions of dollars) ? OS: batch system ? Programming language: FORTRAN amp。t last out the year. The editor in charge of business books for Prentice Hall, 1957 Third generation 1965 – 1980 ? Integrated Circuits and multiprogramming ? IBM’s System/360 mainframe puter with a standard architecture designed to handle both scientific and mercial puting Third generation 1965 – 1980 ? Prerequisite: interrupt, Channel I/O ? channel I/O is a generic term that refers to a highperformance input/output (I/O) architecture that is implemented in various forms on a number of puter architectures, especially on mainframe puters. ? In the past they were generally implemented with a custom processor, known alternately as peripheral processor, I/O processor(IOP), I/O controller, or DMA controller. ? A channel program is a sequence of I/O instructions executed by the input/output channel processor in the IBM System/360 and subsequent architectures. ? OS: Multiprogramming/timesharing, spooling ? Spooling use disk as a very large buffer for input/output devices ? Oses Developed ? MULTICS (father of all modern OSes) ? UNIX (System V, BSD) ? POSIX (by IEEE) ? MINIX (by Tanenbaum) ? Linux (originated by Linus Torvalds, inspired by MINIX) Multiprogrammed Batch Systems ? Several jobs are kept in main memory at the same time, and the CPU is multiplexed among them. ? Multiprogramming increases CPU ultilization by anizing jobs such that CPU always has one to execute. 作業(yè)狀態(tài)轉(zhuǎn)換示意圖 后備狀態(tài) 提交 狀態(tài) CPU P1 P2 P3 運(yùn)行 I/O 作業(yè)調(diào)度 進(jìn)程調(diào)度 完成狀態(tài) 外存盤交換區(qū) 外存就緒 外存阻塞 中級(jí)調(diào)度 OS Features Needed for Multiprogramming ? I/O routine supplied by the system. ? Memory management– the system must allocate the memory to several jobs. ? CPU scheduling – the system must choose among several jobs ready to run. ? Allocation of devices. Job Monitor I/O Job A Job B Scheduling Type I/O Disk I/O Simple/Multiprogramming Batch System (1) Improve CPU utilization 7%100% (in theory) (2) Improve memory and I/O devices utilization (3) Increase system throughput Advantages of Multiprogramming Characteristics of Multiprogrammed Batch Systems:
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