CSE 1720 Business Information Technology and Systems Are
CSE 1720 Business Information Technology and Systems Are you comfortable with the term Business ? Lecture 5 Input / Output Source Data Automation Data Storage System Development CSE 1720 Semester 1 2005 Week 5 /1
Objectives 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 CSE 1720 Semester 1 2005 Week 5 /2
Input/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 CSE 1720 Semester 1 2005 Week 5 /3
Input/Output Devices RESOURCES REQUIRED - Hardware - Software - People - Controls CSE 1720 Semester 1 2005 Week 5 /4
Source 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 CSE 1720 Semester 1 2005 Week 5 /5
Source Data Automation 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. . CSE 1720 Semester 1 2005 Week 5 /6
Source Data Automation 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 CSE 1720 Semester 1 2005 Week 5 /7
Source Data Automation 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 CSE 1720 Semester 1 2005 Week 5 /8
Source Data Automation Automated Teller Machine System 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 HARDWARE CSE 1720 Semester 1 2005 Week 5 /9
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. . ) CSE 1720 Semester 1 2005 Week 5 /10
Source Data Automation Automated Teller Machine System 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 CSE 1720 Semester 1 2005 Week 5 /11
System Source Data Automation Automated 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 CSE 1720 Semester 1 2005 Week 5 /12
Output Devices VIDEO DISPLAY - Color - Reversal - Highlighting - Blink - Addressable Positions - Resolution Liquid Crystal Displays Plasma Displays Graphics CSE 1720 Semester 1 2005 Week 5 /13
Output Devices IMPACT NON IMPACT PRINTERS Daisy Wheel Dot Matrix Line Printer Barrel Printer Thermal Electrostatic Inkjet Bubble Xerographic Laser Color Plan Printers CAD Images Graphics CSE 1720 Semester 1 2005 Week 5 /14
Output Devices Some Print Considerations: - Speed (chars/sec, lines/min, pages/min) - Quality (draft, letter, graphic) - Color (B/W, Multi-color, shaded) - Size 16 pt, 20 pt, 24 pt, 32 pt - 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 CSE 1720 Semester 1 2005 Week 5 /15
Data, Data Storage and Devices CSE 1720 Semester 1 2005 Week 5 /16
Some Aspects of Data A major benefit of Computing is RETRIEVAL OF DATA Some Considerations Volumes Contents Media Storage/Access Method STORAGE What data How long What form ACCESS Why How From Where By Whom Access Controls Timeliness and Accuracy Response Time CSE 1720 Semester 1 2005 Week 5 /17
Data 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) CSE 1720 Semester 1 2005 Week 5 /18
Data 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 ? CSE 1720 Semester 1 2005 Week 5 /19
Data 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 CSE 1720 Semester 1 2005 Week 5 /20
Data 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 Field Record is any member of a set representation 1 or more characters (also known as a Data Item) 1 or more Data Items or Fields (related) CSE 1720 Semester 1 2005 Week 5 /21
Record/File Construction A character : any ONE of 256 possible representations field names date(8) name (20) salary(5) address(30) Date of Birth(8) A record called ‘personnel’ 15 -07 -2001 Smith, J 60 The Avenue, Windsor 65800 16 -09 -1964 data values A number of these records is known as a ‘FILE’. A name is given to this file e. g. PERSONNEL CSE 1720 Semester 1 2005 Week 5 /22
Terminology • 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 CSE 1720 Semester 1 2005 Week 5 /23
Mass Storage Media Main Considerations: 1. Speed of Access 2. Type of Access - Serial, Sequential, Direct (Random) 3. Cost of (i) Read / write equipment (ii) Media 4. Capacity and Density 5. Compression / Decompression (usage efficiency) 6. Portability 7. Re-use and Life 8. Reliability 9. Recovery procedures 10. Upgrade capability / restrictions 11. Suitability for technology development e. g. objects 12. Archival suitability - for what period, and in what conditions CSE 1720 Semester 1 2005 Week 5 /24
Media 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 used as a log file for processing recovery, audit) CSE 1720 Semester 1 2005 Week 5 /25
Some Secondary Storage Devices Magnetic Tape (Approx 600 Mb) Cassette Tape ( 0. 5 Mb to 2 Gb) Cartridge Tape (Streaming Tape) (10 Mb -3 Gb) Optical Tape Magnetic Disk Floppy Disk Up to 8 Gb. Expected to improve to Terabyte level Many Variations 100 Mb to 100 Gb 360 Kb to 1. 4 Mb (also 20 Mb and 100 Mb) Winchester Disk Special Hard Disk with Built In Read/Write heads Optical Laser Disk “WORMS” CD-ROM 700 Mb + Optical Card ( Laser Card ) 2 Mb to 10 Mb CSE 1720 Semester 1 2005 Week 5 /26
Data 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 CSE 1720 Semester 1 2005 Week 5 /27
Typical Magnetic Tape Layout Inter. Record Gap IRG Header Record Data Record 1 Data Record n+1 Data Record 2 Data Record n+2 Data Record n Trailer Record. . . . Records are in Serial or Sequential(ordered) arrangement May be in unordered sequence if device is used as a Log file CSE 1720 Semester 1 2005 Week 5 /28
File Access Methods 1. Sequential Access Record 1 Record 2 Record 3 Record 4 . . . . Record n 2. Direct Access R 2 R 4 R 3 R 1 R 5 CSE 1720 Semester 1 2005 Week 5 /29
Indexed-Sequential Access Method (a) (b) (c) (d) (e) (f) x x x O 5(e) R 6(a) R 1(a) O 4(d) R 3(c) R 2(a) R = Record O = Overflow area Record accessed directly Sorted Index (a) (b) (c) (d) (e) (f) x x x O 5(e) O 4(d R 1(a) Records Accessed Sequentially R 3(c) R 2(a) CSE 1720 Semester 1 2005 Week 5 /30
Indexed File Layout 5012345 7943251 8264301 8512345 8864309 8999257 Primary Index 1 2 3 4 5 6 7 3 Index 6 on 4 Number 1 2 7 5 8512345 8812345 5012345 8264301 8999257 7943251 8864309 Index on Name AGLAVAL 3 DINADIN 7 DODINAS 6 JONES 5 VESPASIAN 2 SMITH 4 WELLINGTON 1 Secondary Index WELLINGTON VESPASIAN AGLAVAL SMITH JONES DODINAS DINADIN 0301 0311 0345 0452 0101 0452 CSE 1720 Semester 1 2005 Week 5 /31
Other File Organisations and Indexes Partitioned Index Sequential List Inverted File Types of Indexing : Hash, Sequential, B Tree, B+ Tree CSE 1720 Semester 1 2005 Week 5 /32
Methods of Input and Processing BATCH : Delayed Input Delayed Processing ON-LINE : Approach : Immediate Input Immediate Processing/Response CSE 1720 Semester 1 2005 Week 5 /33
Other Storage Forms MICROFORM: C. O. M. Computer Output to Microfilm Microfiche C. I. M. Computer Input from Microforms Advantages: Reduced storage Space, Long life Disadvantages: Needs viewer equipment Updated by replacement ************ Microprocessor aided retrieval systems Manual control retrieval systems CSE 1720 Semester 1 2005 Week 5 /34
Terminology 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. ’ CSE 1720 Semester 1 2005 Week 5 /35
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 CSE 1720 Semester 1 2005 Week 5 /37
System 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 CSE 1720 Semester 1 2005 Week 5 /39
Information System Development Cycle INCLUDES : Inception Development Installation Utilisation Termination CSE 1720 Semester 1 2005 Week 5 /40
Information 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 ! CSE 1720 Semester 1 2005 Week 5 /41
System Investigation - Feasibility Study —> Management Review System Analysis —> Management Review System Design —> Management Review System Development —> Management Review System Implementation —> Management Review System Maintenance and Review —> Management Review CSE 1720 Semester 1 2005 Week 5 /42
Information System Development Cycle Phases 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 CSE 1720 Semester 1 2005 Week 5 /43
1. System Investigation (Feasibility Study - Ranking Process) 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 CSE 1720 Semester 1 2005 Week 5 /44
2. 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 CSE 1720 Semester 1 2005 Week 5 /45
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 CSE 1720 Semester 1 2005 Week 5 /46
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 CSE 1720 Semester 1 2005 Week 5 /47
5. 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 CSE 1720 Semester 1 2005 Week 5 /48
6. 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) CSE 1720 Semester 1 2005 Week 5 /49
System 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 CSE 1720 Semester 1 2005 Week 5 /50
The 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 CSE 1720 Semester 1 2005 Week 5 /51
An 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 CSE 1720 Semester 1 2005 Week 5 /52
System Methodology 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 CSE 1720 Semester 1 2005 Week 5 /53
System Methodology 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 CSE 1720 Semester 1 2005 Week 5 /54
System Methodology 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) CSE 1720 Semester 1 2005 Week 5 /55
A Typical Project Plan Task / Week 1 Analysis Design Review Programming Implementation - Plan - Manuals System Testing Review Acceptance Test Review Results Handover 2 3 4 5 6 7 CSE 1720 Semester 1 2005 Week 5 /56
Hopefully, this does not represent you ! CSE 1720 Semester 1 2005 Week 5 /57
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