Systems & Systems Analysis Yale Braunstein School of Information Management & Systems UC Berkeley

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.)

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)

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.

Functions of the Systems Analyst Forms design & control Procedure writing & procedure manual control Records management Report control Office & workplace layout Work simplification studies (This is not an exhaustive list.)

SYSTEM DEVELOPMENT METHODOLOGIES

What Is a Methodology? A formalized approach or series of steps Examples Process-Centered Data-Centered Object-Oriented

Waterfall Development Method IS 208 28-Aug-18 Waterfall Development Method Intro: Systems & Systems Analysis

More detail Define problem Outline system study Obtain background information & understand interactions Understand existing “system” Define system requirements Design new system / generate alternatives Design system controls Prepare cost comparisons Sell system to management Provide for implementation, follow-up, evaluation

Pros and Cons of the Waterfall Method 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

Alternatives to the SDLC Parallel Development Rapid Application Development (RAD) Phased Development Prototyping Spiral Development Packaged Systems

Parallel Development Method IS 208 28-Aug-18 Parallel Development Method Intro: Systems & Systems Analysis

Pros and Cons of Parallel Development Reduces Scheduled Time Still Uses Paper Documents Less Chance of Rework Sub-projects May Be Difficult to Integrate

Rapid Application Development CASE tools JAD sessions Fourth generation/visualization programming languages Code generators

Three RAD Categories Phased development A series of versions Prototyping System prototyping Throw-away prototyping Design prototyping

How Prototyping Works

Throwaway Prototyping

Criteria for Selecting the Appropriate Methodology Clear user requirements Familiar technology Complexity Reliability Time schedule Schedule visibility

How broad should the analysis be? What is the system being studied? Look at one or more of five levels: Entire firm, organization One division Departmental interaction Functional areas within a department A specific problem area within a function

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”

“Black-box” models OUTPUTS INPUTS External Environment

Sources Text, Chapter 1 “History of Project Management”