unix操作系统 外文文献译文和原文.doc

1．What is an UNIX
An operating system originally developed by Dennis Ritchie and Ken Thompson at AT&T Bell Laboratories that allows a computer to handle multiple users and programs simultaneously．Since its development in the early 1970s，UNIX has been enhanced by many individuals and particularly by computer scientists at the University of Uantornia，Berkeley（known as Berkeley Software Distribution UNIX，or BSD UNIX）．This operating system is available on a wide variety of computer systems，ranging from personal computers to mainframes，and is available in other related forms．AIX is in implementation that runs on IBM workstations，A/UX is a graphical version that runs on Macintosh computers；Solaris runs on Intel microprocessors．UnixWare is the Novell implementation of UNIX．NetWare for UNIX is an Original Equipment Manufacturer（OEM）version of NetWare that can run on a UNIX host．

2．The UNIX System Can Support Many Users
Depending on the machine being used，a UNIX system can support from one to over one hundred users，each concurrently running a different set of programs．The cost of a computer that can be used by many people at the same time is less per user than that of a computer that can be used by only a single person at a time．[1] The cost is less because one person cannot generally use all of the resources a computer has to offer．No one can keep the printer going constantly，keep all the system memory in use，keep the disk busy reading and writing，keep the tape drives spinning，keep the modem in use，and keep the terminals busy．[2] A multiuser operating system allows many people to use all of the system resources almost simultaneously．Thus，utilization of costly resources can be maximized，and the cost per user can be minimized．These are the primary objectives of a multiuser operating system．
3．The UNIX System Can Support Many Tasks
The UNIX operating system allows each user to run more than one job at a time．You can run several jobs

UNIX操作系统
1．什么是UNIX操作系统
UNIX操作系统最早是由美国电话电报公司（AT&T）贝尔实验室的丹尼斯•里奇和肯• 汤普森开发的，它允许计算机同时处理多用户和程序。从20世纪70年代开发以来，UNIX经由许多个人和公司，特别是加利福尼亚大学伯克利分校的计算机科学家的努力而得到增强（通常称为伯克利软件发行部UNIX或BSD UNIX）。这种操作系统在各类计算机系统，即从个人计算机到大型机上广泛使用，并可以其他相关形式使用。AIX是运行在IBM工作站上的版本；A/UX 是在Macintosh计算机上运行的图形版本；Solaris是在英特尔微处理器上运行的版本；UnixWare是UNIX的Novell实现。 UNIX的Net-Ware是可以在UNIX主机上运行的NetWare原始设备制造商（OEM）版本。
2．UNIX系统能支持多用户
与所使用的机器有关，UNIX系统可以支持一个用户到上百个用户，每个用户都并发地运行一组不同的程序。由很多人同时使用一台计算机的人均成本比一次只允许一个人使用一台计算机的成本要低。成本低是因为一个人不能总是使用计算机的所有资源：没有一个人总是占用打印机，占用系统全部内存，总是使磁盘忙于读写，使磁带驱动器一直转动，一直占用modem，总使终端忙碌；一个多用户操作系统允许很多人几乎同时使用所有的系统资源。因此，使昂贵资源的利用率达到最高，户均费用最小，这就是多用户操作系统的主要目标。