Systems Design, Implementation and Operatio

3213 Words Mar 22nd, 2012 13 Pages
CHAPTER 20

SYSTEMS DESIGN, IMPLEMENTATION AND OPERATION

In chapter 18 we focused on the first phase of the Systems Development Life Cycle – Systems Analysis. Chapter 20 deals with the remaining four phases:

- conceptual systems design - physical systems design - systems implementation and conversion - operation and maintenance

CONCEPTUAL SYSTEMS DESIGN

In the conceptual systems design phase, the developer creates a general framework for implementing user requirements and solving problems identified in the analysis phase.

As shown in Figure 20-1 on page 747 HC (page 637 SC), there are three main steps in conceptual design:

1. evaluating design alternatives, 2. preparing design specifications, and
…show more content…
Typically prepared in response to a management request. Example: analysis of impact of a new government requirement on profitability

3. Triggered exception reports have a prespecified content and format but are prepared only in response to abnormal conditions. Example: cost overruns reports

4. Demand reports have a prespecified content and format but are prepared only on request.
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File and Database Design

Various company segments need to store data in compatible formats so that data can be shared across units.

Table 20-3 on page 750 HC (page 640 SC) summarizes some of the more important file and database design considerations:

1)storage medium

2) processing mode

3) maintenance

4) size

5) activity level

Input Design

Systems designers must identify the different types of data input and optimal input methods.

There are two principal types of data input:

• Forms

• Computer screens

Considerations for input design are shown in Table 20-4 on page 751 HC (page 641 SC).

|1 |Medium |6 |Personnel |
|2 |Source |7 |Frequency |
|3 |Format |8 |Cost |
|4 |Type |9 |Error detection & correction |
|5 |Volume |10 |General1 |

Note #1:
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