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Systems & Systems Analysis

Yale Braunstein

School of Information Management & SystemsUC Berkeley

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Working Definition of “System”

A system is a network of inter-related procedures joined together to perform an activity or accomplish an objective

(Note that the level of technology is NOT specified—there are low-tech systems as well as high tech systems)

(Also note that the “breadth” of the system is not specified. More on this later.)

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So, what is a “procedure” ?

A procedure is the precise series of instructions that that explain: What is to be done Who will do it When it will be done How …

(Note the parallels to programming terminology)

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Types of Systems

Open system: does not provide for its own control

Closed system: automatically controls or modifies it own operations

A recurring thought: It is important to look at how the system handles exceptions.

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Functions of the Systems Analyst

1. Forms design & control

2. Procedure writing & procedure manual control

3. Records management

4. Report control

5. Office & workplace layout

6. Work simplification studies

(This is not an exhaustive list.)

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SYSTEM DEVELOPMENT METHODOLOGIES

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What Is a Methodology?

A formalized approach or series of steps

Examples Process-Centered Data-Centered Object-Oriented

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Waterfall Development Method

Evaluation!

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More detail1. Define problem

2. Outline system study

3. Obtain background information & understand interactions

4. Understand existing “system”

5. Define system requirements

6. Design new system / generate alternatives

7. Design system controls

8. Prepare cost comparisons

9. Sell system to management

10. Provide for implementation, follow-up, evaluation

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Pros and Cons of the Waterfall Method

Pros Cons

Identifies systems requirements long before programming begins

Design must be specified on paper before programming begins

Long time between system proposal and delivery of new system

[Digression on “internet time” goes here.]

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Alternatives to the SDLC*

Parallel Development

Rapid Application Development (RAD)

Phased Development

Prototyping

Spiral Development

Packaged Systems

*Systems development life cycle

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Parallel Development Method

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Pros and Cons of Parallel Development

Pros Cons

Reduces Scheduled Time

Less Chance ofRework

Still Uses PaperDocuments

Sub-projects May BeDifficult to Integrate

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Rapid Application Development

CASE tools

JAD sessions

Fourth generation/visualization programming languages

Code generators

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Three RAD Categories

Phased development A series of versions

Prototyping System prototyping

Throw-away prototyping Design prototyping

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How Prototyping Works

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Throwaway Prototyping

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Criteria for Selecting the Appropriate Methodology

Clear user requirements

Familiar technology

Complexity

Reliability

Time schedule

Schedule visibility

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How broad should the analysis be?

What is the system being studied?

Look at one or more of five levels:1. Entire firm, organization2. One division3. Departmental interaction4. Functional areas within a

department5. A specific problem area within a

function

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The “sub-optimization” problem Sub-optimal: what is best from the narrow

point-of-view may not be best when other functions, divisions, etc., are taken into consideration. Similar to “externalities” in economics Examples:

–Freight & passenger service using same routes

– Internal & external networks–Carriers & content providers

“Sub-optimal” is different from “non-optimal”

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“Black-box” models

INPUTS OUTPUTS

External Environment

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Sources

Text, Chapter 1

“History of Project Management”