a contemporary computer system consists of a central processing unit(CPU),pritnary storage, input
devices,output
devices,secondary
storage
and
communications devices,the characteristics of the central processing
unit and primary storage largely determine a computer's speed and capacity to solve problem.th cpu manipalates
raw data into a more useful form and controls the other parts of the computer system.thile primary storage
temporarily stores data and program instructions during processing.input devices,such as keyboards,optical
scanner,and computer mice,convert adata into electronic form for input into the computer.output devices,
such as printers and video display terminals.convert electronic data produced by the computer into form
itelligible to humans.secondary storage devices store data and program instructions when they are not being
used in processing.communication devices allow the computer to be connected to communications networks.buses
are paths for transinining data and singnals sraong the various parts of the computer system.
the internet has been the focus of so much attention because it is
the single largest and fastest.
growing implementation of an infomation superhighway.the terminformation superhighway refers to high-speed
telecommunications networks that are national or international in scope and that offer open access(with or without a fee)
to the general public.the internet is having a massive impact on the business world.on university and government communities. and on many individuals as well.this imapact arises from the internet because it vistually eliminates many of the barriers of time and place and does so inexpensively.
一个近代计算机系统包括一个处理单元CPU,主存储器，输入设备，输出设备，副存储器和通讯设备。CPU和主存储器的特点决定了计算机处理问题的速度和能力。CPU把原始数据变成更有有用的形式，并且控制计算机系统的其它设备。在处理过程中，主存储器临时存放着数据和程序指令。输入设备，如键盘，光学扫描仪和鼠标，把数据转化成电信号输入计算机。输出设备，如打印机，显示终端把电信号转化为人可以理解的形式。副存储器存放着没有正被处理的数据。通信设备把计算机连接到通信网络上。总线是计算机各部分传输数据的通路。
因特网成为关注焦点，因为他是信息高速公路应用中发展最大最快的。这里信息高速公路指提供大众收费或免费连接的国内国际范围的
高速电信网络。因特网对世界商业，大学，机构和个人都起着巨大影响。这种影响是由于因特网几乎打破了时间和地域的局限，而且并不昂贵。