信息系统外文翻译--系统的分析与设计

I 附录1 外文翻译(原文)

Systems Analysis and Design

Working under control of a stored program, a computer processes data into

information. Think about that definition for a minute. Any given computer application

involves at least three components: hardware, software, and data. Merely writing a

program isn't enough; because the program is but one component in a system.

A system is a group of components that work together to accomplish an

objective. For example, consider a payroll system. Its objective is paying employees.

What components are involved? Each day，employees record their hours worked on

time cards. At the end of each week, the time cards are collected and delivered to the

computer center, where they are read into a payroll program. As it runs, the program

accesses data files. Finally, the paychecks are printed and distributed. For the system

to work, people, procedures, input and output media, files, hardware, and software

must be carefully coordinated. Note that the program is but one component in a

system.

Computer-based systems are developed because people need information. Those

people, called users, generally know what is required, but may lack the expertise to

obtain it. Technical professionals, such as programmers, have the expertise, but may

lack training in the user's field. To complicate matters, users and programmers often

seem to speak different languages, leading to communication problems. A systems

analyst is a professional who translates user needs into technical terms, thus serving as

a bridge between users and technical professionals.

Like an engineer or an architect, a systems analyst solves problems by combining

solid technical skills with insight, imagination, and a touch of art. Generally, the

analyst follows a well-defined, methodical process that includes at least the following

steps;

1.Problem definition

2.Analysis

3.Design

4.Implementation

5.Maintenance 2 At the end of each step, results are documented and shared with both the user and

the programmers. The idea is to catch and correct errors and misunderstandings as

early as possible. Perhaps the best way to illustrate the process is through example.

Picture a small clothing store that purchases merchandise at wholesale, displays

this stock, and sells it to customers at retail. On the one hand, too much stock

represents an unnecessary expense. On the other hand, a poor selection discourages

shoppers. Ideally, a balance can be achieved: enough, but not too much.

Complicating matters is the fact that inventory is constantly changing, with

customer purchases depleting stock, and returns and reorders adding to it. [1] The

owner would like to track inventory levels and reorder and given item just before the

store runs out. For a single item, the task is easy-just count the stock-on-hand.

Unfortunately, the store has hundreds of different items, and keeping track of each one

is impractical. Perhaps a computer might help.

2-1 Problem Definition

The first step in the systems analysis and design process is problem definition.

The analyst's objective is determining what the user (in this case, the store's owner)

needs. Note that, as the process begins, the user possesses the critical information, and

the analyst must listen and learn. Few users are technical experts. Most see the

computer as a "magic box, "and are not concerned with how it works. At this stage,

the analyst has no business even thinking about programs, files, and computer

hardware, but must communicate with the user on his or her own term.

The idea is to ensure that both the user and the analyst are thinking about the

same thing-Thus, a clear, written statement expressing the analyst's understanding of

the problem is essential. The user should review and correct this written statement.

The time to catch misunderstandings and oversights is now, before time, money and

effort are wasted.

Often, following a preliminary problem definition, the analyst performs a

feasibility study. The study a brief capsule version of the entire systems analysis and

design process, attempts to answer three questions:

1.Can the problem be solved?

2.Can it be salved in the user's environment?

3.Can it be solved at a reasonable cost?

If the answer to any one of these questions is no, the system should not be

developed. Given a good problem definition and a positive feasibility study, the