软件代码量不断增加 oug=om NASA Widow.w ndows Scbn Wrdawswndow.Wndows RedHat Recal Window Vata aI N (1998) 95 s8 NT 50 Unu 62Urur 7.1 xP 10(000) aoc)
软件代码量不断增加
Operating System 操作系统 a program that controls the execution of application programs 用于控制应用程序的执行的程序 An interface between the user and hardware 用户与硬件间的接口 Masks the details of the hardware 屏蔽硬件的细节
Operating System 操作系统 A program that controls the execution of application programs 用于控制应用程序的执行的程序 An interface between the user and hardware 用户与硬件间的接口 Masks the details of the hardware 屏蔽硬件的细节
Services Provided by the Operating System 操作系统提供的服务-1 ◆ Program creation程序开发 editors and debuggers(编辑和调试) :Pmmm程序找行 ◆ Access to devices 外设存取 ◆ Controlled access to files文件取存控制 ● System access系统访问
Services Provided by the Operating System 操作系统提供的服务-1 Program creation 程序开发 – editors and debuggers (编辑和调试) Program execution 程序执行 Access to I/O devices 外设存取 Controlled access to files 文件取存控制 System access 系统访问
Services Provided by the Operating System 操作系统提供的服务-2 ◆ Error detection and response错误检测与响应 internal and external hardware errors内/外硬件错误 memory error内存错误 device failure设备错误 software errors软件错误 arithmetic overflow算法溢出 access forbidden memory locations越权内存访问 operating system cannot grant request of application 操作系统不允许的应用请求
Error detection and response错误检测与响应 – internal and external hardware errors内/外硬件错误 • memory error内存错误 • device failure设备错误 – software errors软件错误 • arithmetic overflow算法溢出 • access forbidden memory locations 越权内存访问 – operating system cannot grant request of application 操作系统不允许的应用请求 Services Provided by the Operating System 操作系统提供的服务-2
Services Provided by the Operating System 操作系统提供的服务-3 ◆ Accounting计帐 collect statistics信息统计 monitor performance性能监控 used to anticipate future enhancements用于后 期系统扩展 used for billing users向用户收费
Accounting 计帐 – collect statistics 信息统计 – monitor performance 性能监控 – used to anticipate future enhancements 用于后 期系统扩展 – used for billing users 向用户收费 Services Provided by the Operating System 操作系统提供的服务-3