通信与专业英语12.ppt

通信专业英语;Unit Twelve Computer Operating System; Operating systems offer a number of services to application programs and users. Applications access these services through application programming interfaces (APIs) or system calls. By invoking these interfaces, the application can request a service from the operating system, pass parameters, and receive the results of the operation. Users may also interact with the operating system by typing commands or using a graphical user interface (GUI). For hand-held and desktop computers, the GUI is generally considered part of the operating system. For large multi-user systems, the GUI is generally implemented as an application program that runs outside the operating system. Common contemporary operating systems include Microsoft Windows, Mac OS X, Linux and Solaris. Microsoft Windows has a significant majority of market share in the desktop and notebook computer markets, while servers generally run on Linux or other Unix-like systems. Embedded device markets are split among several operating systems.; The Microsoft Windows family of operating systems originated as an add-on to the older MS-DOS operating system for the IBM PC. Modern versions are based on the newer Windows NT. Windows runs on x86, x86-64 and Itanium processors. Up to now, Microsoft Windows holds a large amount of the worldwide desktop market share. Windows is also used on servers, supporting applications such as web servers and database servers. In recent years, Microsoft has spent significant marketing and research development money to demonstrate that Windows is capable of running any enterprise application, which has resulted in consistent price/performance records and significant acceptance in the enterprise market. The most widely used version of the Microsoft Windows family is Windows XP, released on October 25, 2001.; In November 2006, after more than five years of development work, Microsoft released Windows Vista,