计算机专业英语第三章课件.ppt

The Operating System Lesson One Summary of operating system An operating system serves as an interface, bridging the gap between hardware and application software. Thus, as we move from hardware to software, it’s appropriate that we consider the operating system first. serve 服务，供应 interface 界面 bridge n.桥；vt.架桥 gap n.缺口，缝隙 thus adv.因而，从而，如此 appropriate adj.适当的 consider vt.考虑，照顾，认为 What exactly dose an operating system do? Basically, it performs a number of support functions. exactly basically support If the application program is to be loaded, there must be a program in memory to control the loading process. That program is the operating system. Typically, the operating system is stored on disk. This objective is achieved by a special program called a boot. Generally, the boot is stored on the first sector (or two) of a disk. Hardware is designed to read this sector automatically whenever the power is turned on. The boot consists of only a few instructions, but they are sufficient to read the rest of the operating system into memory; note how it is seemingly “pulled in by its own bootstraps”. Now, a user can type the commands to load and execute an application program. generally sector designed automatically consists of instructions sufficient rest note seemingly own type load execute Loading programs is only one of the operating system’s many support functions. Basically, it is a collection of software modules that insulate the user from the hardware, thus making the system easier to use. Let’s investigate the primary functions of a typical operating system. collection n.收藏，搜集品 module n.模块 insulate vt.使绝缘，隔离 investigate v.调查，研究 primary adj.第一位的，主要的 The operating system is a collection of programs designed to manage the system’s resources, namely, memory, processors, devices, and information (program and data). Memory Management Fu