Simple batch Systems (简单批处理系统) Monitors(监督程序): Software that controls the running programs Resident monitor is in main memory and available for execution Figure 2.3) Batch jobs together Program branches back to monitor when finished, the monitor would automatically begin loading the next job
Simple Batch Systems （简单批处理系统） • Monitors（监督程序）：Software that controls the running programs • Resident monitor is in main memory and available for execution（Figure 2.3). • Batch jobs together • Program branches back to monitor when finished，the monitor would automatically begin loading the next job
中断处理 常驻监控程序√设备驱动程序 作业序列 控制语言 分界线→ 解释器 用户程序 区域 图23关于常驻监控程序的存储器布局
Job Control Language ( JCl) Special type of programming language Provides instruction to the monitor These instruction are denoted by the beginning or“/ what compiler to use what data to use A simple example. See, P52)
Job Control Language (JCL) • Special type of programming language • Provides instruction to the monitor • These instruction are denoted by the beginning ‘$’ or ‘//’. – what compiler to use – what data to use • A simple example. (See,P52)
Multiprogramming (多道程序设计) 一个支持 Multiprogramming的系统允许多道程序 同时准备运行;当正在运行的那道程序因为某 种原因(比如等待输入或输出数据)暂时不能 继续运行时,系统将自动地启动另一道程序运 行;一旦原因消除(比如数据已经到达或数据 已经输出完毕),暂时停止运行的那道程序在 将来某个时候还可以被系统重新启动继续运行
Multiprogramming （多道程序设计） • 一个支持Multiprogramming的系统允许多道程序 同时准备运行；当正在运行的那道程序因为某 种原因（比如等待输入或输出数据）暂时不能 继续运行时，系统将自动地启动另一道程序运 行；一旦原因消除（比如数据已经到达或数据 已经输出完毕），暂时停止运行的那道程序在 将来某个时候还可以被系统重新启动继续运行
Multiprogramming (2 Programs) When one job needs to wait for 1/o, the processor can switch to the other job Program A Run Walt Run Walt Program B Walt Run Walt Run Walt Run Run RunRun Combined Walt Walt B B TIme (b)Multlprogramming wlth two programs
Multiprogramming （2 Programs） • When one job needs to wait for I/O, the processor can switch to the other job