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Lecture 5

Lecture 5. CSE1720 Business Information Technology and Systems. Are you comfortable with the term Business ?. Input / Output Source Data Automation Data Storage System Development. Objectives of this Lecture.

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Lecture 5

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  1. Lecture 5 CSE1720 Business Information Technology and Systems Are you comfortable with the term Business ? Input / Output Source Data Automation Data Storage System Development

  2. 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

  3. 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

  4. Input/Output Devices RESOURCES REQUIRED • -Hardware • - Software • - People • - Controls

  5. 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

  6. 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 ....

  7. 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

  8. 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

  9. Source Data AutomationAutomated Teller Machine System HARDWAREconsists 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

  10. 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 ..)

  11. Source Data AutomationAutomated 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

  12. 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

  13. Output Devices VIDEO DISPLAY - Color - Reversal - Highlighting - Blink - Addressable Positions - Resolution Liquid Crystal Displays Plasma Displays Graphics

  14. Output Devices PRINTERS IMPACTDaisy Wheel Dot Matrix Line Printer Barrel Printer NON IMPACTThermal Electrostatic Color Inkjet Plan Printers Bubble CAD Images Xerographic Graphics Laser

  15. Output 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

  16. Data, Data Storage and Devices

  17. Some Aspects of Data A 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

  18. 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)     

  19. 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 ?

  20. 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

  21. 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 is any member of a set representation Field 1 or more characters (also known as a Data Item) Record 1 or more Data Items or Fields (related)

  22. Record/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’ data values 15-07-2001 Smith, J 60 The Avenue, Windsor 65800 16-09-1964 A number of these records is known as a ‘FILE’. A name is given to this file e.g. PERSONNEL

  23. 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

  24. 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

  25. 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)

  26. Some 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 100Gb Floppy Disk 360Kb to 1.4Mb (also 20 Mb and 100Mb) Winchester Disk Special Hard Disk with Built In Read/Write heads Optical Laser Disk “WORMS” CD-ROM 700Mb + Optical Card ( Laser Card ) 2Mb to 10Mb

  27. 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

  28. Typical Magnetic Tape Layout InterRecord Gap IRG Data Data Data Header Record Record 1 Record 2 Record n Data Data Trailer Record Record n+1 Record n+2 .................................. Records are in Serial or Sequential(ordered) arrangement May be in unordered sequence if device is used as a Log file

  29. File Access Methods 1. Sequential Access Record 1 Record 2 Record 3 Record 4 ........ Record n 2. Direct Access R2 R4 R3 R1 R5

  30. Indexed-Sequential Access Method (a) x (b) x (c) x (d) x (e) x (f) x R = Record O = Overflow area O5(e) R6(a) O4(d) Record accessed directly R3(c) R1(a) R2(a) Sorted Index (a) x (b) x (c) x (d) x (e) x (f) x O5(e) Records Accessed Sequentially O4(d R1(a) R3(c) R2(a)

  31. Indexed File Layout Index on Name 5012345 3 Index AGLAVAL 3 7943251 6 on DINADIN 7 8264301 4 Number DODINAS 6 8512345 1 JONES 5 8812345 2 VESPASIAN 2 8864309 7 SMITH 4 8999257 5 WELLINGTON 1 Primary Index Secondary Index 1 8512345 WELLINGTON 0301 2 8812345 VESPASIAN 0311 3 5012345 AGLAVAL 0345 4 8264301 SMITH 0452 5 8999257 JONES 0101 6 7943251 DODINAS 0101 7 8864309 DINADIN 0452

  32. Other File Organisations and Indexes Partitioned Index Sequential List Inverted File Types of Indexing : Hash, Sequential, B Tree, B+ Tree

  33. Methods of Input and Processing BATCH : Delayed Input Delayed Processing ON-LINE : Approach : Immediate Input Immediate Processing/Response

  34. 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

  35. 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.’

  36. 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

  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

  38. Information System Development Cycle INCLUDES : Inception Development Installation Utilisation Termination

  39. 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 !

  40. System 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

  41. 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

  42. 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

  43. 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

  44. 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

  45. 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

  46. 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

  47. 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)

  48. 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

  49. 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

  50. 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

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