Lecture 5

CSE1720 Semester 1 2005 Week 5 /1

Lecture 5Lecture 5

CSE1720 Business Information Technology and SystemsCSE1720 Business Information Technology and Systems

Are you comfortable with the term Business ?

Input / OutputSource Data Automation Data Storage System Development


Objectives of this LectureObjectives of this Lecture

• To look at the purpose of Input/Output devices (and also the range)

• To look at the application of Engineering practice to data capture - Source Data Automation

• To examine a well known user system - the Automated Teller Machine system

• Aspects of Security ; System Error Messages• Data Storage and Some Data Storage Devices• Data Access methods• System Development


Input/Output DevicesInput/Output Devices

Communicate with computer processes

- Supply data for processing

- Source of commands

- Provide an enquiry capability

Some Associated SYSTEM functions

01. INPUT - Collection of data

- Conversion to computer form

- Entered/Accepted to processes

02. OUTPUT - Presented in ‘Human’ form

- Stored in computer form


Input/Output DevicesInput/Output Devices

RESOURCES REQUIRED

- Hardware

- Software

- People

- Controls


Source Data AutomationSource Data Automation

AIMS To capture data as near as possible to the TRANSACTION occurrence (time)

To capture data as close as possible to the SOURCE

To use direct machine readable data where possible

To capture FIXED data by * prerecording

* computer tables

To capture data without data media



Some Considerations:

Flexibility

Ability to Use New Hardware

Reflect and Satisfy Customers’ needs

Reliability - Error Free/Very Low Error Rate Customer Confidence levels

Response Times - Checkouts/A.T.Ms/Medical Benefits

Library/Garages/ etc ....



TYPICAL HARDWARE

Point of Sale Terminals - POS and EFTPOS

Electronic Cash Registers

Magnetic Strip (Stripe) Readers

Optical Card Readers

Magnetic Ink Character Readers

Bar Code readers

Image Scanners

Transducers (Public Transport, Private Transport)

(City Link, Tollways, Vehicle Location)

- RACV, Motoring magazines



More hardware:

Mark Sense Readers

Data Pads

Data Pens .

Digitisers

Voice Recognition

Touch Sensitive Screens - have you tried the Myer screens ?

or the Monash system - Level 2, S Block ? (and others)

Specialised Icon Keyboards

Mouse Driven menus activating screen buttons - Windows


Source Data AutomationAutomated Teller Machine System


HARDWARE consists of

1. Card stripe reader (soon a chip reader)

2. Keyboard (variable input)

3. Screen Display - may have multi color

- intensity variations

4. Function Keypad

5. Printer

6. Note Dispenser

7. Lock / Unlock Device (Accounts, payments, deposits

transfers)

SOFTWARE consists of Communications and Applications programs


Source Data Automation Automated Teller Machine System

Source Data Automation Automated Teller Machine System

The USER is led through a ‘menu’ - Range of options

1. WITHDRAW / DEPOSIT / BALANCE

2. CHEQUE / SAVINGS / CREDIT / OTHER

3. AMOUNT - Paid in

- Withdrawn

- Transferred

4. USER VERIFICATION

User acceptance of Transaction

(OK key CANCEL key) - 1 MUST be used

5. REMOVE CARD PROMPT

6. OTHER PROCEDURE PROMPTS (take cash ..)




SECURITY FEATURES

1. Account number verification ( ? exists)

2. P.I.N. verification

3. Transaction Log

4. Error messages - PIN incorrect

- Wrong card type

- Cannot connect

5. Timeouts

6. Screen cover - Open at beginning, close at end of

transaction

7. User Acceptance/Proceed ‘OK’

Reject / Cancel button


System Source Data AutomationAutomated Teller Machine

System Source Data AutomationAutomated Teller Machine

SYSTEM ERROR MESSAGES• Open/Closed Panel Indicator (Green/Red)

• Amount Selected Not Available

• Amount Selected in Excess of Daily Withdrawal Limit

• Machine Does Not Dispense $10 or $20 ($50 only)

• P.I.N. identification incorrect

• System Faults - Printer, Note Dispenser


Output DevicesOutput Devices

VIDEO DISPLAY - Color

- Reversal

- Highlighting

- Blink

- Addressable Positions

- Resolution

Liquid Crystal Displays

Plasma Displays

Graphics


Output Devices Output Devices

PRINTERS

IMPACT Daisy Wheel

Dot Matrix

Line Printer

Barrel Printer

NON IMPACT Thermal

Electrostatic Color

Inkjet Plan Printers

Bubble CAD Images

Xerographic Graphics

Laser


Output DevicesOutput Devices

Some Print Considerations:

- Speed (chars/sec, lines/min, pages/min)

- Quality (draft, letter, graphic)

- Color (B/W, Multi-color, shaded)

- Size 16pt, 20pt, 24pt, 32pt- Font (Algerian, Antique, Clarendon, Bookman,

Times New Roman, Playbill, Universal, Arial)

- Continuous Feed, Sheet Feed, Labels

- Number of Copies

- Noise Factor

- Lint and Dust Factor

- Paper Handling


Data, Data Storage and DevicesData, Data Storage and Devices


Some Aspects of DataSome Aspects of DataA major benefit of Computing is RETRIEVAL OF DATA

Some Considerations STORAGE What data How long What form

ACCESS Why How Volumes From Where Contents By Whom Media Access Controls Storage/Access Method Timeliness and Accuracy Response Time


Data RepresentationData Representation

Question : How many blue objects can you see ?

Five or 5 ? That’s 5 in the decimal system or 510

In the Binary system 5 is represented as 0101

In the Ternary system 5 is represented as 12

In the ASCII system 5 is represented as 00110101 (8 bits)


Data and its Internal StructureData and its Internal Structure

• We use the term ‘byte’ to indicate a string of 8 bits (binary digits - 0 and 1)

• This give us the capacity to represent 256 different ‘characters’ e.g. 1, a, A %, $ ....

(ASCII and EBCDIC)

That is not enough:• 16 Bits gives a capacity to represent 65,000 separate

‘characters’• Unicode offers 34,000 ‘characters’ - represents all

current languages

• Why do we need this expanded capacity ?


Data and Its FormsData and Its Forms

Data consists of

Digits 0, 1, 2 ………

Characters (lower case) a,b,c,

(upper case) A,B,C,D

Special symbols &, %, #, @

Images in 2 and 3 dimensions X-Rays, MIR’s

Sound

Video (Images and Sound)

Each form must be

represented clearly (accurately)

recognised

processable


Data Representation -2Data Representation -2

- SPECIAL SYMBOLS + - $ \ / () * Cr, Dr,

- Combinations of Non Signed Numerics Alphabetics Specials e.g. 914 Dandenong Rd., Caulfield East, 3145 (P.O. Box 197)

HIERARCHY OF DATA

Character is any member of a set representationField 1 or more characters (also known as a Data Item)Record 1 or more Data Items or Fields (related)


Record/File ConstructionRecord/File Construction

A character : any ONE of 256 possible representations

field names date(8) name (20) address(30)

salary(5) Date of Birth(8)

A record called ‘personnel’

A number of these records is known as a ‘FILE’. A name is given to this file e.g. PERSONNEL

datavalues15-07-2001 Smith, J 60 The Avenue, Windsor 65800 16-09-1964


TerminologyTerminology

• FILE = Groups of RECORDS with a common basis e.g. Staff Records, Student Records, Telephone Directory Spare Parts Listings

• VOLUME Generally used for (1) Collection of files (2) Physical multiple media 3 diskettes or CDs needed to hold Spare Parts File

• DATABASE Collection of Files (or Tables) Database Management System manages access, retrieval

and updates to a Data Base


Mass Storage MediaMass Storage Media

Main Considerations:1. Speed of Access2. Type of Access - Serial, Sequential, Direct (Random)3. Cost of (i) Read / write equipment (ii) Media4. Capacity and Density5. Compression / Decompression (usage efficiency)6. Portability7. Re-use and Life8. Reliability9. Recovery procedures10. Upgrade capability / restrictions11. Suitability for technology development e.g. objects12. Archival suitability - for what period, and in what conditions


Media TermsMedia Terms

• Magnetic Disk:

Tracks, Sectors, Allocation Units, Clusters,

Density, Organisation

• Magnetic Tape:

Packing Density, Blocks, Inter-record Gap, Track (7 or 9), Rewind Speed, Organisation -(Serial or Sequential. Can also be usedas a log file for processing recovery, audit)


Some Secondary Storage DevicesSome Secondary Storage Devices

Magnetic Tape (Approx 600Mb)Cassette Tape ( 0.5Mb to 2Gb)Cartridge Tape (Streaming Tape) (10Mb -3 Gb)

Optical Tape Up to 8Gb. Expected to improve to Terabyte level

Magnetic Disk Many Variations 100Mb to 100GbFloppy Disk 360Kb to 1.4Mb (also 20 Mb and 100Mb)

Winchester Disk Special Hard Disk with Built In Read/Write headsOptical Laser Disk “WORMS” CD-ROM 700Mb +Optical Card ( Laser Card ) 2Mb to 10Mb


Data Storage and Retrieval MethodsData Storage and Retrieval Methods

• SEQUENTIAL STORAGE and RETRIEVAL

records are retrieved, one at a time, in the order in which they were stored

• DIRECT ACCESS STORAGE and RETRIEVAL

records are stored and retrieved in any order

• INDEXED SEQUENTIAL STORAGE and RETRIEVAL

records are stored sequentially but with an index which allows both sequential and direct access


Typical Magnetic Tape LayoutTypical Magnetic Tape Layout

Header Record Data Data Data

Data Data Trailer Record

Record 1 Record 2 Record n

Record n+1 Record n+2 ..................................

InterRecord Gap IRG

Records are in Serial or Sequential(ordered) arrangement

May be in unordered sequence if device is used as a Log file


File Access MethodsFile Access Methods1. Sequential Access

Record 1 Record 2 Record 3 Record 4 ........ Record n

2. Direct Access

R1R5

R3

R2

R4


Indexed-Sequential Access MethodIndexed-Sequential Access Method

(a) x(b) x(c) x(d) x(e) x(f) x R1(a)

R2(a)

R3(c)

O4(d)

O5(e)

Sorted Index

R = RecordO = Overflow area

(a) x(b) x(c) x(d) x(e) x(f) x

O5(e)

O4(d

R3(c)

R2(a)

R1(a)

R6(a)

Record accesseddirectly

Records AccessedSequentially


Indexed File LayoutIndexed File Layout

5012345 3 Index AGLAVAL 37943251 6 on DINADIN 78264301 4 Number DODINAS 6 8512345 1 JONES 58812345 2 VESPASIAN 28864309 7 SMITH 48999257 5 WELLINGTON 1

1 8512345 WELLINGTON 03012 8812345 VESPASIAN 03113 5012345 AGLAVAL 03454 8264301 SMITH 04525 8999257 JONES 01016 7943251 DODINAS 01017 8864309 DINADIN 0452

Primary Index Secondary Index

Index onName


Other File Organisations and IndexesOther File Organisations and Indexes

Partitioned Index Sequential

List

Inverted File

Types of Indexing : Hash, Sequential, B Tree, B+ Tree


Methods of Input and ProcessingMethods of Input and Processing

BATCH : Delayed Input

Delayed Processing

ON-LINE : Approach : Immediate Input

Immediate Processing/Response


Other Storage FormsOther Storage Forms

MICROFORM:

C.O.M. Computer Output to Microfilm Microfiche

C.I.M. Computer Input from Microforms

Advantages: Reduced storage Space, Long lifeDisadvantages: Needs viewer equipment Updated by replacement ********** ************ *********

Microprocessor aided retrieval systemsManual control retrieval systems


Terminology Mix UpTerminology Mix Up

• People who extract minerals (metal ore, coal etc) from the Earth are known as miners.

• A marketing analyst (Monash graduate) was in a town and asked a ‘captured’ shopper this question:

Are you a miner ?

And the reply was - ‘Of course I’m not a minor ! I’m 25.’


We need

1. To introduce the System Development Life Cycle as a basis for system development and installation

2. To briefly look at some aspects of Project Management in association with the System Development Life Cycle


System ConstructionSystem Construction

A Systematic Approach gives Developers and Users

1. A method which defines systems and

subsystems

2. Processes to ensure that the project (study)

is managed


Information System Development Cycle Information System Development Cycle

INCLUDES :

Inception

Development

Installation

Utilisation

Termination


Information System Development CycleInformation System Development Cycle

STAGES OF DEVELOPMENT:

Define Problem Define Objectives

Develop Alternative Solutions Make Business Rules / Assumptions

Define Constraints Define Criteria for Decision Making

Collect Representative Data Construct Models

Evaluate Alternatives MAKE DECISIONS !


System System

System Investigation - Feasibility Study

—> Management Review

System Analysis


System Design


System Development


System Implementation


System Maintenance and Review



Information System Development CyclePhases of a Systems Project

Phase 1 : Feasibility Study

Determine the scope of the problem

Is it worth developing? Cost/Benefit ?

Phase 2 : Systems Analysis

Assess the problem in detail

Phase 3 : Systems Design

Create the ‘blueprint’ for the new system

Phase 4 : Systems Development

Build the system - purchase the equipment and

software. Test the components

Phase 5 : Implementation and Evaluation (Review)

Convert to new equipment / software, train staff

Evaluate the new system


1. System Investigation1. System Investigation

01. Consider, Define, Select a System to be Developed / Modified

02. Determine Information Needs

03. Define Objectives, Resources, Constraints, Costs/Benefits, Timescale

OUTPUTS: 1. Report to Management 2. Decision

(Feasibility Study - Ranking Process)


2. System Analysis2. System Analysis

01. Conduct Detail Analysis of Information Needs

02. Develop System Resource Requirements

03. Develop Appropriate Organisation Structure

04. Analyse Current Information Systems (Objectives, Content, User Views, Performance)

05. Develop Input/Output, Storage, Processing Requirements

Outputs: 1. Report to Management (Updated Resources/Costs/Benefits) 2. Decision


3. System Design (Logical)3. System Design (Logical)

01. Develop Alternative Designs (Scenarios)

02. Analyse and Refine Options

03. Design Input/Output Requirements

04. Design Data Base/ Processing Options

05. Develop Processing Procedures

06. Develop Hardware / Software / Human Resource Specifications Outputs: 1. Report to Management 2. Decision


4. System Development (Physical)4. System Development (Physical)

01. Specify, Plan, Develop Software Needs

02. Specify Precise Hardware Requirements

03. Finalise Human Resource Needs

04. Solve Software Needs ( Request for Proposals )

( Tendering, Contracts) 05. Solve Hardware Needs

06. Place Orders as Appropriate

Outputs 1. Report to Management 2. Decision


5. System Implementation5. System Implementation

01. Install Hardware, Software Test, and Document Test Results

02. Train Personnel to Operate System

03. Train Personnel to USE System

04. Convert Files/Controls/Data Streams/Data Bases

05. Install by either (A) Direct (B) Phased (C) Parallel (D) Pilot approach Outputs: 1. Report to Management 2. Decision


6. System Maintenance6. System Maintenance

01. Monitor Performance, Results

02. Evaluate Effectiveness

03. Evaluate User Acceptance

04. Maintain Controls

05. Test System ( Failures, Recovery, Access, Response)

06. Evaluate/Monitor/Control Changes

On Going Management Control (Budget)


System MethodologySystem Methodology

The major weakness of the use of this approach is that in some (? many) cases new and critical factors have emerged in the Business which are not, or only partially, caught in the developed system.

Watch new web design system - and the rate of replacement

The SDLC is OK when there is much IT and Business experience and Management is ‘looking ahead’ to see what will be needed in 6, 9, 12 months time - and this is built into the system


The Waterfall ApproachThe Waterfall Approach

The System Development Life Cycle is a structured framework which consists of sequential processes

A previous approach was the Waterfall method. This required that the tasks in one stage were completed before work could proceed to the next stage

The current practice is for system developers to go backwards and forwards through the stages as necessary


An 8 stage systems developmentAn 8 stage systems development

1. Systems Investigation

2. Systems Analysis

3. Systems Design

4. Software Development

5. Testing

6. Implementation

7. Operation

8. Maintenance

Go Back to a Previous Stage or Stop



Another method is prototyping

This effectively creates a small model, quickly

Users work with the prototype at the analysis and design stages, and recommend alterations

When senior management is convinced that the prototype accurately reflects ‘the goods’, then the full system is created



Prototyping is applicable where user needs are not clear, or users refuse to be pinned down, and like the ‘let’s try it and see approach’. Costs are generally lower.

Another major advantage is that users get the system which they require



Another method is the ‘End User Development’

In this approach the user develops the system rather than having IT internal or consultant people doing this work

A a rule of thumb, the End User approach is ideal when the system is ‘inexpensive’ (not INXS) and can be associated with many PC/Microsoft based development systems

(not really recommended for Oracle based projects)


A Typical Project PlanA Typical Project Plan

Task / Week 1 2 3 4 5 6 7Analysis

Design

Review

Programming

Implementation

- Plan

- Manuals

System Testing

Review

Acceptance Test

Review Results

Handover


Hopefully, this does not represent you !

Lecture 5

Documents

Transcript of Lecture 5