Chapter 5 Operating System Computer English 计算机专业英语—电子教程.pptVIP

Computer English Chapter 5 Operating System Jobs, programs and processes A program is the classical view of a computation. It consists of a set of program units, including program units obtained from libraries, which constitute an object code to be executed. A process is an execution of a program or of a part of a program. It differs from a program when concurrent programming techniques are used for coding the program. In such a case many processes can execute a program or a part of a program. 程序是计算的传统观点，它由一系列程序单元构成，包括从库中获取的程序单元，并组成可执行的目标代码。进程是一个程序或一个程序部分的一次执行。在应用并行编码技术时，许多进程可以执行同一程序或其一部分，这时进程与程序是不同的。 5.2 Evolution of OS Function Jobs, programs and processes A job is a computational structure which is a sequence of programs. It consists of a sequence of job steps, each job step constituting the execution of a program. Thus, a job for the compilation and execution of a Pascal program involves the following three job steps---execution of the Pascal compiler to compile the Pascal program, execution of the linker to prepare the compiled program for execution and execution of the object program which has just been linked. 作业是一个程序序列的计算结构。它由一系列作业步组成，每一步都是一个程序执行的一部分。例如，一个对Pascal程序进行编译和执行的作业包括以下三步：用编译程序对程序进行编译，用链接程序准备对编译好的程序的执行，以及执行刚刚链接好的目标程序。 5.2 Evolution of OS Function Jobs, programs and processes Note that it is not meaningful to execute a job step unless each of the previous job steps has executed success fully, e.g. linking is not meaningful unless compilation was successful. The notion of a job was important in early computer systems which did not support interactive computing it is of marginal relevance in most contemporary systems, for example the BAT files of MS DOS and shell scripts of Unix resemble the notion of jobs. 每一步都要在前一步执行成功后才能执行。比如，除非编译成功，否则链接就毫无意义。在早期不支持交互计算的计算机系统中，作业的概念很重要。它在现代系统中也有应用，如MS-DOS中的Bat文件和Unix中的shell脚本。 5.2 Evolution of OS Function New Words Expressions interrupt vt. n.中断 bulk n. 成批，大量，整体 monolithic adj.整体式的,一致的;n.单片 share vt.