操作系統(tǒng)原理緒論(英文課件)-文庫吧資料
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【正文】 ry and on disk (the CPU is allocated to a job only if the job is in memory). ? A job is swapped in and out of memory to the disk. ? Online munication between the user and the system is provided。 Toy Story 2。 A Bug39。t see Windows as a longterm graphical interface for the masses. A Lotus Software Development official, while demonstrating a new DOS version, 1989 History of Operating Systems ? ? Bill Gates suggested IBM that they should look at CP/M (by Gary Kildall) ? The biggest mistake of all: ? Kindall refused to sign a nondisclosure agreement ? IBM went back to Bill Gates and signed a contract with him to write an OS for their new home puter ? MSDOS was based on QDOS, the Quick and Dirty Operating System written by Tim Paterson of Seattle Computer Products ? QDOS was based on Gary Kildall39。 Assembly ? Computer: Mainframes ? Low CPU utilization slow mechanical I/O devices IBM STRETCH DEC PDP1 Early Batch System ? bring cards to 1401 ? read cards to tape ? put tape on 7094 which does puting ? put tape on 1401 which prints output Batch Systems ? Hire an operator 設(shè)置一個操作員 ? User ? operator ? Reduce setup time by batching similar jobs 批量處理同類作業(yè)減少了設(shè)置時間 ? OS’s main task: Automatic job sequencing – automatically transfers control from one job to another. ? Resident monitor ? initial control in monitor 初始化管理程序 ? control transfers to job 轉(zhuǎn)換控制到作業(yè) ? when job pletes control transfers back to monitor 作業(yè) =程序 +數(shù)據(jù) +處理步驟 Memory Layout for a Simple Batch System Control Cards ? Problems 1. How does the monitor know about the nature of the job (., Fortran versus Assembly) or which program to execute? 2. How does the monitor distinguish (a) job from job? (b) data from program? ? Solution ? Introduce control cards Control Cards (Cont.) ? Special cards that tell the resident monitor which programs to run $JOB $FTN $RUN $DATA $END ? Special characters distinguish control cards from data or program cards 特定的字符把數(shù)據(jù)卡片和程序卡片區(qū)分開來 Structure of a typical Fortran Monitoring System job $JOB card specifies: ? the max runtime in minutes ? The account number to be charged ? The programmers name $FORTRAN card: tells the operating System to load Fortran piler $RUN means run the program with The following data $END end of job A Famous Remark ! I have travelled the length and breadth of this country, and talked with the best people, and I can assure you that data processing is a fad that won39。 Operating System Goals ? Manage system resources to make them utilized and shared effectively. ? Organize puter’s workflow reasonably in order to improve system performance (response time /throughput). ? Provide user interfaces to simplify user operations. (Convenience、 Efficiency、 Scalability、 Open) Abstract View of System Components Virtual machine 裸機在每增加一層軟件后，就成為一個功能更強的機器，通常將這個“新的功能更強的機器”稱為 “ 虛擬機 ” Chapter 1: Introduction ? What is an Operating System? ? History of Operating Systems ? The Operating System Zoo History of Operating Systems ? First generation 1945 – 1955 ? vacuum tubes, plug boards (no OS) ? Second generation 1955 – 1965 ? transistors, batch systems ? Third generation 1965 – 1980 ? ICs, multiprogramming ? Fourth generati
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