计算机如何工作

How a Computer Works
 
　　Let's use the system pictured in Figure 1-3 to illustrate how a typical computer works．A computer is controlled by a stored program: thus, the first step in using the machine is to copy the program from diskette into memory Now, the processor can begin executing instructions．Input data from the keyboard are stored in memory. The processor manipulates the data, storing the results back into memor3. Finally, the results are output.
　　Memory's contents are easy to change. Thus, when one set of data has been processed, the program can be repeated, reading and processing new data, and generating new output. If the data can be changed, why not the program? When a program is finished, anew one can take its place in memory, allowing the computer to process completely different data. One minute it can generate pay checks from labor data under control of a payroll program. The next minute, it can prepare bills from invoices under control of a play roll program .The next minute, it can prepare bills from invoices under control of a billing program. Later, this same collection of components, controlled by yet another program, can read
Statistical data and produce a bar chart or sense the movements of a joystick and manipulate the position of an imaginary spaceship on a display screen.

　　The physical components of a computer-the processor, memory, input device, and output device-are its hardware. You can see them, touch them, an (feel them. Program and data are different, existing only as electronic pulses stored in memory. Software is a general term for programs．

翻译：

计算机如何工作
  
　　让我们利用示意图1-3的系统，来说明一台典型的计算机是如何工作的。计算机是由存储器程序来控制的；这样，使用机器的第一步，就是将程序从软盘复制到存储器中去。现在，处理器能够开始执行指令了。从键盘输入的数据被存储在存储器中。处理器处理没数据，将结果存回到存储器中。最后，结果（作为）输出。
　　存储器的内容是易于改变的，这样，当一组数据已被处理完时，程序可被重复（执行），（通过）读入及处理新的数据，（又会）产生新的输出。如果数据可以改变，那么，程序为什么不能改变呢？当一个程序结束时，一个新程序可以在内存中取得其位置，这就可以允许计算机处理完全不同的数据。一个时间，它可以在工资发放程序的控制下，从劳务数据产生工资单。在下一个时间，它可以在账单程序控制下，从发票准备账单。以后，还是同样的部件集合体，在另外的程序控制下，可以读入统计数据，并产生直方图，或者感知操纵杆的运动，在显示屏上 操纵想象的宇宙飞船的位置。 
　　一台计算机的实际部件—处理器，存储器，输入设备及输出设备—这些是它的硬件，你可以看见它们，触摸它们和感知它们。程序及数据则不同，它们仅仅以存储在内存中的电脉冲的形式存在着。软件是各种程序的一个通用术语。