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SYSTEM DESIGN
Introduction
Business
Rules | Structured
English | Pseudocode
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Unit
Test Specification Example
System| System Development | Analysis Techniques | SYSTEMS MODELING | System design
Development Methodologies - Waterfall (SDLC), RAD, Agile/Xtremme Programming, BPR
Software reuseability | Software metrics
CASE Tools, Development tools | HCI Tools | File Formats | Coding Standards
Intelligent Agents | Decision Support Systems
Architecture |SOFTWARE ARCHITECTURE : ADL TOOLS | TOGA Architecture Model
STRATEGIC PLANNING: Benchmarking Balanced Scorecarding Boston Matrix Cliff Bowan's
TECHNOLOGY MANAGEMENT LINKS | Article Reviews |
GLOSSARIES:
Glossary of internet terms | Dr. T's Internet Glossary | Square one Glossary of Internet Terms | WebQuest Web Glosssary |
ASCII = American National Standard Code for Information Interchange EBCDIC = Extended Binary Coded Decimal Interchange Code Chart | Specialized IT Glossaries
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TECHNOLOGY MANAGEMENT LINKS | Article Reviews |
Introduction
Systems design is the process of defining the architecture, components, modules, interfaces, and data for a system to satisfy the specified requirements as agreed to by the major stakeholders.
There is some overlap with the disciplines of systems analysis, systems architecture and systems engineering. While product development includes perspectives from marketing, design, and manufacturing into a single end-product, design is the act of taking the marketing information and creating the design of the product to be manufactured. Hence, systems design is the process of defining and developing systems to satisfy specified requirements of the user.
While the five major components of a system design
are: User Interface, Data
Design, Process Design, Communications
and Human Capital, the major System Specification's
Components are: Objectives : Programs | Business Rules
| Hardware Requirements | Project Plan |Cost Estimate.
Specifying process logic can be done using Decision
Tables/Business Rules
, Structured
English, Nassi-Schneiderman Charts or
Action Diagrams
Structured design usually
consists of Documents and or Data Flow Diagrams (DFD), Structure Chart, Module
Specifications and or pseudo code
Design Strategy Issues consist
of: 1) Requirements | Software | Hardware | Infrastructure |Implementation
| Organization
2. Outsourcing | 3. Off-the-shelf | 4. In-house
Design methodologies alternatives
include: SDLC | RAD | XTREME PROGRAMMING | SCRUM | AGILE
While maintenance choices may
include: Maintenance: Corrective – Fix programming errors, Adaptive – Adapt to environment
, Improvement – Use to solve new problems, Preventative – prevent future problems
Business
Rules Example
Decision Task: Loan Approval
Conditions: Income > 20K /year
Employment > 2 Years
Credit History: Good/Poor
Credit Cards: >5
RULES:
Income < 20K & CrHistory (Poor) - REJECT
Income < 20K & CrHistory (Good) - ACCEPT
Income < 20K & Employmt < 2 Years - REJECT
Income > 20K & CrHistory (Poor) - REJECT
Income > 20K & Cards <5 & Employmt < 2 Years - REJECT
Else ACCEPT
Structured
English
Structured English specifications consists of
Imperative verbs and Terms defined in Data Dictionary, where one specification is used for each functional primitive in the set of Data Flow Diagram used to describe the rules used in the transformation that occurs as data moves through the process.
Example:
1. For each New Stock Request:
Find authorization form such that Reference Number is equal to Request Number of New Stock Request:
2. If no match, discard New Stock Request. Otherwise:
Write Purchase Order for Ordered Item
Select Supplier for which Ordered Item appears in Supplier Catalog Entry
Copy Supplier Name and Address on Purchase Order number onto New Stock Request
File New Stock Request with Authorization Form
Unit Test
Specification example
testStartBanner
SYNPOSIS
testStartBanner()
DESCRIPTION:
Displays “start test” banner for given test
INPUT PARAMETERS:
Ptr-> testname A text message with a max. length of 80 characters. Loeaded by the unit test caller
OUTPUT PARAMETERS
None
RETURNS
None
Pseudocode
An outline that can
easily be converted into real programming statements
For example, the
pseudocode for a sort routine might be written:
while
not at end of list
compare adjacent elements
if second is greater than first
switch them
get next two elements
if elements were switched
repeat for entire list
- -
Screen
- -
Form Report
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Dialog Design
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Data Element
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Structure Design
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Program
- -
Procedure Design
- - Network
backbone
- -
Applications
- -
Management
- -
Knowledge
workers
- Labor
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