張惠娟副教授mszhj@163com-在線瀏覽
2024-12-14 18:22本頁面
【正文】 rt SMP ? Asymmetric multiprocessing ?Each processor is assigned a specific task。 processors municate with one another through various munications lines, such as highspeed buses or telephone lines. ?Advantages of distributed systems. ?Resources Sharing ?Computation speed up – load sharing ?Reliability ?Communications 27 Distributed Systems ?Network Operating System ?provides file sharing ?provides munication scheme ?runs independently from other puters on the work ?Distributed Operating System ?less autonomy between puters ?gives the impression there is a single operating system controlling the work. 28 RealTime Systems ?Welldefined fixedtime constraints. ?Hard realtime system. ?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 ?Limited utility in industrial control or robotics ?Useful in applications (multimedia, virtual reality) requiring advanced operatingsystem features. 29 發(fā)展規(guī)律 ? 操作系統(tǒng)發(fā)展是由 低層硬件 、 軟件技 術(shù) 與上層 應(yīng)用需求 的發(fā)展所推動的 ? 操作系統(tǒng)每一步發(fā)展都是權(quán)衡的結(jié)果 30 常用操作系統(tǒng) 微軟 OS產(chǎn)品 UNIX產(chǎn)品 自由軟件 IBM的 OS產(chǎn)品 其它 OS產(chǎn)品 31 微軟 OS產(chǎn)品 32 UNIX產(chǎn)品 ?發(fā)展 ?產(chǎn)生： 69年 AT＆ T公司貝爾實(shí)驗(yàn)室 ?第二階段（ 7379）：免費(fèi)擴(kuò)散 ?第三階段（ 7585）：商用版本的出現(xiàn)（ 77年）
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