The IT Story Begins With…

Jacquard Loom - 1801

And Continues with…

Difference Engine: 1822-65 (Babbage and Lovelace)

And then …

ITR (1889-1914) + CTR (1911-1914) => IBM

+

Analysis

Operational Support

Planning

Design

Implementation

SDLC

The Systems Development Life Cycle

The Traditional Approach

Ready

Fire

Aim

There are different approaches to Software Development

• Reverse Engineering

• The Traditional Waterfall Model

• Exploratory Programming

• Boehm’s Spiral Model

• Agile/Extreme Programming

• Pattern Languages

Reverse EngineeringReverse Engineering

1. Specifications

2. Design

3. Construction

4. Test and Use

1. Test and Use

2. Deconstruction

3. Document Design

4. Formulate Specifications

EngineeringEngineering

Traditional Waterfall (Our Text)

Analysis

Operational Support

Planning

Design

Implementation

Planning

If you can keep your head about you

When all around you others are losing theirs

…..then maybe you just don’t understand the problem!

Planning Activities

• System Request

• Preliminary Investigation– Interviews on needs and practices– Surveys– Collecting forms

• Analysis of the Business Case

• Feasibility Study

Analysis Activities

• Identify the stakeholders

• Research existing practices

• Research real (vs requested) needs

• Requirements Modelling

• Prepare Design specification

Design

• Document or Die!

• Use of specific techniques important– Data Flow Diagrams– UML Diagrams/Use-Case– Database Normalization

• Prototype – a quick and dirty demo – not production quality

Implementation

• Code (according to specifications)

• Test!

• Revise specifications as needed (go back to previous SDLC stages if necessary)

• Installation

Operational Support

• Training

• Implement security (why wait?)

• Modifications

Maintenance

Development

Software Development

$90%

$10%

• Hacking

• Cost effective only forsmall projects

• Useful for solving novel problems

• Risky (high failure rate)

• Fun, but hard to sell to management

Exploratory Programming

Object Oriented Design

• Model using “real world” Objects

• Analyze with Use/Case Examples

• Model Systems Behaviour with UML

Spiral Model (Barry Boehm)

Agile (Extreme) Programming

• Small teams• Developers work very closely with clients• Rapid turnaround of project features• Paretto’s Law: 80% of the job takes 20% of the

effort – to complete the job will take the remaining 80% therefore: most clients will be happy to pay for 80% functionality and balk at the extra cost of the remaining 20% - so don’t do it.

Pattern Languages

• Applications are likebuildings

• Most projects can bebased on knownarchitectural patterns

• Learning the patterns thatwork helps ensure futuresuccess

Which Methodology Works?

• Different Techniques fit different situations• The corporate culture is a major factor in

choosing an approach• The method of development is itself a

pattern – learn to follow success.• Don’t be too rigid – you can always fake it!

- A Rational Design Process (and how to fake it),by Prof. David L. Parnas & Paul Clemens, 1985

Types of Software Systems

• Transaction Processing (TP)• Management Information Systems (MIS)• Knowledge Management Systems• User Productivity Software • Real Time Systems (RTS)• Enterprise Computing• Systems Software and Utilities

• Information Systems Integration

Transaction Processing

• A. – Atomicity (All or nothing)

• C. – Consistancy (the books balance)

• I. - Isolation (don’t affect each other)

• D. – Durability (permanent record)

Performance Measurement: TPS (Transactions per second)

MIS

• Text also uses the term “Business Support Systems” – MIS is more common

• MIS does not need to be real time

• Decision Support

• Data Mining/Data Warehouses

TP collects/generates data – MIS summarizes and reports

Knowledge Management

• Expert Systems– Interview the experts and uncover the rules they use

– usually 20-80 – relatively small #– Applicable to small problem domains, not large– Use of Knowledge Engines, languages such as

Prolog) – Rules + facts => Diagnosis• Fuzzy Logic (ie: Omron, rice cooker example,

OCR)• Content Management

– Silos of information (Ann Rockly)– Ontologies for organizing my meaning

• Search: Altavista; Google; Lucene; HTDig

User Productivity Software

• Office Suites/Personal Software

• Groupware

Enterprise Software

• Enterprise Resource Planning (ERP)– SAP– Oracle Financials, PeopleSoft– Walmart’s Inventory System– American Airline: SABRE

• Bet the company type software (Federal Express)

• Integrates essential company functions

Real Time Systems

• Used in process control, embedded devices

• Specialized operating systems (QNX, Symbian, HP/RTE) or no OS at all

• Issue is guaranteed response time – can’t wait for paging, garbage collection

• Make sure the system is not overloaded (in order to guarantee response time)

• Examples?

Systems Software & Utilities

• Operating Systems• Device Drivers• Backup Software (ie: Time Machine)• Virus Protection• Programmer’s Tools

– Compilers and Interpreters– IDE’s– Computer Aided Software Engineering (CASE)– Debuggers

• Performance Monitors • Database Engines

Embedded Devices

Mashups

SystemsSoftware& Utilities

EnterpriseComputing

MISRealTime

KnowledgeManagement

UserProductivity

TransactionProcessing

Software Integration

Games (How to classify?)

What is the Market Place?

Rule of 4 – How IT Companies Make Money

1. Product Sales

2. Maintenance and Support

3. Projects and Consulting

4. Training

Business to Business (B2B)

• Electronic Data Interchange using XML and agreed upon standard protocols– Banking– Ordering inventory

Business to Consumer

• Web Based Software– Advertising– Product Information– Home Banking

• Games• Personal Productivity

Tools

Identifying Stakeholders And Their Needs

• Top Managers

• Middle Managers & Knowledge Workers

• Supervisors and Team Leaders

• Operational Employees

Information Needs

CEO

Top Managers

Middle Management

Supervisors &Team Leaders

Operational Employees

short term goalsDetailed Info

Long term goalsSummarized Info

Lets not forget…

• Customers

• Vendors

• Stockholders

• Competitors (Industry Standards that have to be met – companies often need to co-operate with the competition)

Chapter 2 –Systems Planning

Strategic Planning

• Mission Statement– Short –briefly describes the core purpose of the

company or project or team– Sets a direction – a “moral compass”

• Principles/Core Values

• Business Plan– Long Term Goals– Mid Term Goals– Short Term Goals

Strategic Planning Question

In pursuing this project are we supporting our mission statement, principles and goals

If not – why are we doing it?

Should we drop the project?

Should we change how we define ourselves?

Mission Statements

What is the Mission Statement of

• Toronto’s Police Force

• The Canadian Cancer Society?

• Humber College

What is your Mission Statement?

SWOT Analysis

Feasibility Study

• Economic

• Technical

• Operational

• Scheduling

Making a Business Case

• Why are we doing this project?

• What is the project about?

• How does this solution address key business issues?

• How much? (ROI) How long? (Payback)

• Will it cause a hit in productivity?

• Risks of going ahead? Of NOT doing it?

Making a Business Case (2)

• If we don’t know where our goals are – how do we know we’ve arrived. How do we measure success?

Making the Business Case

What other choices are there? (Missed opportunities?)

Reasons for System Projects

• Improved Service

• Support for new products and services

• Better performance

• More information

• Stronger Controls (Security)

Improving any of the “Qualities of a Good System”

Discussion

Collecting the current position of every vehicle in the TTC.

Internal Factors Affecting Systems Projects

• Strategic Plan

• Management Directives

• User Requests

• The IT department

• The weight of Existing Systems

External Factors Affecting Systems Projects

• Technology (ie: Office 2007, Vista, Multitouch, Wireless, RFID, the Internet, Web 2.0)

• Suppliers - Radio Freq. ID chips (RFID) – EPOD (Electronic Proof of Delivery, Just In Time Management (JIT)

• Customers: CRM Software (Customer/Supplier Relationship Management)

More External Factors

• Competitors

• The Economy

• Government

Cost/Benefit Analysis

• Tangible/Intangible

• Direct/Indirect

• Recurring/Non-Recurring

• Capital

• Overhead

• Supplies

• Personnel