1. A BRIEF INTRODUCTION TO UNIX OPERATING SYSTEM
Huifeng Shao
$1. Operating System and UNIX
(a). General Operating System
(b). UNIX Operating System
$2. The Feature and Architecture of UNIX
(a). Features
(b). Internal Structure
$3. UNIX Comparing with Other Operating System
$4. UNIX Market

2. $1. Operating System and UNIX
(a). What is an Operating System?
Operating System is a necessary tool for using a computer to run application programs.

3. $1. Operating System and UNIX
(b). UNIX Operating System
Unix Operating System is more than an operating system in traditional sense. Unix system includes a set of libraries and a set of applications.
General functions of UNIX System includes:
Providing system service
Providing a user interface
Coordinating the sequence of events
Controlling resources
Enforcing security
Providing tools

4. $2. The Feature and Architecture of Unix
(a). Main Feature
Multiuser Capabilities: UNIX enables more than one person to user the computer at the same time through a process called “TIME-SHARING”
Advantages: (1). Low cost per user; (2). Central administration; (3). Shared resources
Multitasking Capabilities: UNIX can perform more than one task at a time for each user.
Advantage: greatly increases productivity
Device Independence: UNIX enables you to use files and devices interchangeably. Advantage: much easy to move data to and from files or devices
Portability and Open System: It’s the most notable feature. Unix has capability to run on a wide range of different computer makes and models (open system). No other operating system even approaches this level of portability.
Advantages: (1). Almost no cost to convert to a new system (little/no training and minimal effort of converting data and software); (2). Interoperability between systems, e.g. application programs can be written once and versions made available for all kinds of machines.
The Tools Approach: UNIX has hundreds of small, build-in programs called TOOLS, each of which accomplishes a common, simple task. You can accomplish complex tasks by combining tools in various ways.
Advantage: (1). Flexibility; (2). Speed; (3). Structured approach

5. $2. The feature and Architecture of Unix
(b). Internal Structure

7. $4. UNIX Market