操作系統(tǒng)原理緒論(英文課件)-閱讀頁
2024-12-23 09:40本頁面
【正文】 多道性、無序性、調(diào)度性（兩級） Question ?兩個 /兩個以上的作業(yè)同時入主存 ?處于宏觀運行狀態(tài) ?共享所有系統(tǒng)資源 Can you tell me the concept of “Multiprogramming”? A Famous Remark ! There is no reason anyone would want a puter in their home. Ken Olson, president, chairman and founder of Digital Equipment Corp., 1977 Tourth Generation 1980 – Present ? personal puters were developed after LSI (Large Scale Integration) circuits were invented. ? First Microputer: ? Intel 8080 CPU + attached 8inch floppy disk ? First disk based OS: CP/M (Control Program for Microputers) ? Programming languages: C/C++, Java, …… ? OS: DOS, Windows, MacOS, Linux …… A Famous Remark ! We don39。s CP/M ? Microsoft bought the rights to QDOS for $50,000 History of Operating Systems ? ? Early MSDOS was very primitive but later versions included advanced features taken from UNIX ? The early OS for microputers were based on users typing in mands from the keyboard ? Douglas Engelbart from SRI invented the Graphical User Interface (GUI) with windows, icons, menus, and mouse. History of Operating Systems ? ? Steve Jobs saw the value of GUI in a PC and developed the Apple puter with GUI (Apple Macintosh) in his garage. ? He is also the cofounder of Pixar which has created very successful animated films: Toy Story 。s Life。 Finding Nemo。 when the operating system finishes the execution of one mand, it seeks the next “control statement” not from a card reader, but rather from the user’s keyboard. ? Online system must be available for users to access data and code. TimeSharing Systems (Cont.) 主機 終端 RealTime Systems ? Often used as a control device in a dedicated application such as controlling scientific experiments, medical imaging systems, industrial control systems, and some display systems. ? Welldefined fixedtime constraints. 嚴格的時間限制 RealTime Systems (Cont.) RealTime Systems (Cont.) RealTime Systems (Cont.) RealTime Systems (Cont.) ? Hard realtime system 硬實時系統(tǒng) ? Secondary storage limited or absent, data stored in shortterm memory, or readonly memory (ROM) ? Conflicts with timesharing systems, not supported by generalpurpose operating systems. ? Soft realtime system 軟 實時系統(tǒng) ? Limited utility in industrial control or robotics ? Useful in applications (multimedia, virtual reality) requiring advanced operatingsystem features. PersonalComputer Systems ? Personal puters – puter system dedicated to a single user. ? I/O devices – keyboards, mice, display screens, small printers. ? User convenience and responsiveness. ? Can adopt technology developed for larger operating system, often individuals have sole use of puter and do not need advanced CPU utilization of protection features. 可采用大型操作系統(tǒng)研發(fā)的技術(shù)，個人獨占計算機不需要高級CPU使用的保護技術(shù) Migration of OperatingSystem Concepts and Features Parallel Systems ? Multiprocessor systems with more than one CPU in close munication. ? Tightly coupled system緊耦合系統(tǒng) – processors share memory and a clock。 master processor schedules and allocates work to slave processors. ? More mon in extremely large systems Symmetric Multiprocessing Architecture Distributed Systems ? Distribute the putation among several physical processors. ? Loosely coupled system – each processor has its own local mem
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