system analysis & design compiled by sardar mohammad
TRANSCRIPT
System Analysis & Design
Compiled
by
Sardar Mohammad
2
Why do business depends on Information more than ever
• Global competition
• Intense pressure for quality
• Information technology can mean the difference between survival and failure
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What is required for successful business information systems?
• The right hardware and software
• A team of talented, motivated people who use information technology to achieve business goals
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Business Process Modeling It is used to represent a company’s operations and
information needs Business profiles, models and processes
Business profiles Defines a company overall functions, process, organization
product, services, customers, suppliers, competitors, constraints, and future direction
To understand the company the System Analyst should first develop business profile
Business models Graphical representation of business functions consisting of
business processes such as sales, accounting, and purchases Business processes
Describes the specific events, tasks, and desired results
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Introduction to Information Systems (IS)
• System– A group of related procedures for a particular business
function– There may one system or a no.of sub-systems e.g.
Accounting, Admission, Payroll…
• Function– E.g, Payroll, Accounts, Admission …
• Procedure– The rules and regulations required to accomplish the
functions. E.g. procedure for admission function…
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IS Components
• The effective use of H/W, S/W, Data, Procedures and People to achieve specific results that support the company’s business objective
• H/W– Physical layer of IS
• S/W– System S/W
– Application S/W
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IS Components
• Data– Facts and Figures used to take part in
processing for information
• Procedures– The activities that must be performed by the
users who work in the system
• People– Users, End Users, Programmer…
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Characteristics of IS
• Timeliness
• Completeness
• Conciseness – To the point
• Understandable
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Business Organizations
• Production Oriented (Industrial) Companies– Manufacturers e.g. Intel Corp
• Service Companies– Those who sales products manufactured by
other companies, information e.g. Telecommunication Companies, Publishers
• Combined Industrial & Service Companies– Manufacturers and Sale also e.g.IBM
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Business Organizations
• Governmental Organization– Just as service Companies
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Companies Complexity
• Relationships with other systems– A system process data and its O/P is made I/P to
another System e.g. Fee system ->Accounts
– IS of one company interface with the system operated by the other company e.g. one businessman place order to another businessman, here ordering form of one system is I/P to the purchasing system of another businessman
– Electronic Data Interchange (EDI), both the companies may not be using computer systems
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Companies Complexity
• Boundaries– It indicates boundaries between the subsystems where a
systems starts and where it ends e.g. Student Information System and Accounts
• Specialized Business needs– E.g. School system, Transcript Processing…, Hospital
System
• Size of Company– E.g. small shop and Bank with more than five
branches…
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Types of IS
• Operational System– The system process data generated day to day business
transactions e.g.order enter,accounts…
• Management IS– Is a computer based system that generates timely and
accurate information for top, middle and lower management. E.g. Registering students in a course the management should know whether a student has been Admitted, Registered in Semester and the Selected the Courses along with the abidance of business rules
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Types of IS
• Decision Support System (DSS).– The information that are not part of routine by
Operational and Management IS e.g. effect of company if sales are increased by 10%, What- if analysis.
– Usually it needs data from both internal company as well as external data is required. E.g. Internal data is sales, students address and External Data is trends, Population…etc
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Types of IS
• Executive Support/Information System ESS/EIS– Decision
• Structured– Already decided reports required for decision usually
periodically
• Unstructured – The reports that cannot be determined and information is
undefined e.g. Yammy’s experts wants data about the tastes of people of a particular locality
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Types of IS
– Semi-Structured.• Between Structured and Semi-Structured e.g. impact of
inflation on product cost.
• ESS deal with the information providing for Unstructured decisions.
• Expert System.– It simulates human reasoning and decision making by
combining the subject knowledge of human experts called knowledge base and inference rules that determine how the knowledge is used to reach a decision e.g. automobile fuel system, best place for oil drilling.
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Types of IS
• Office system– Office Automation Systems. It facilities a
company in many ways e.g. emails, fax,video conferencing, word processing, spread sheets, presentation, internet access, graphics/charts…etc
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Steps to achieve optimum IS
• Standardization• Single source of Data
– E.g. if a requisition is there it should be used by the entire organization
• Integrate Independent data processing• Exception reporting• Eliminating duplication• Direct communication• Equipment
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Organizational Level
• Operational Personnel– They spend most of the time in repetitive tasks in
performing function following specific procedures
– They interact with the system at a detail level
• Lower management– They are supervisors, team leaders, coordinators etc.
They direct the operators and ensure the right tool, material, resources and making necessary decisions
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Organizational Level
• Middle Management– They are directors, managers to develop plans,
allocate resources to achieve business objective in a process call Tactical Planning
– They need less detail and need summaries
• Top management– They frame policies, goals called Strategic
Planning
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System Development Techniques and Tools
• Modeling– It produce graphical representation of concepts or process that
systems developer can analyze, test, and modify– Business model or requirement model describes business functions– Data model describes data structure and design– Network model portrays design and protocols of
telecommunication– Object model describes objects– Process model describes system logic and processes that
programmer use to develop necessary code module• Prototyping• CASE (Computer Aided System Engineering)• JAD
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Overview of System Development Methodologies
• Structured Analysis– Process-Centered
• OO Analysis
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SDLC – System Planning
• System Request– Generated by a management identify a problem
• Feasibility – Preliminary Investigation– Economic– Technical– Operational– Recommendation
Factors
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SDLC – System Analysis
• To know exactly how the current system works to determine what the system should do
• Fact Fining
• Requirement Analysis
• System Requirements
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SDLC – System Design
• To develop an IS that exactly satisfy the requirement of a business.
• Design of procedures, database, strategies ...
• The design is documented by the name System Design Specification.
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SDLC – System Implementation
• Application programs are written, tested and implemented
• Assessment of Post Implementation System
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SDLC – Operation & Support
• Maintenance of the system
• Enhancement in the system
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Consideration for building IS
• Complete the phases in sequence
• Focus on End Product
• Cost-effectiveness
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IS Department
• Operational Group– Operators, Backup operators…
• Technical Group– Installs OS, DBMS
• Application Group– Analyze, design, test program…
• Information Center– Training, Technical Information desk…
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System Analyst - Duties
• Investigates, analyze, design, develops, install, evaluates and maintain a company’s IS
• Involve in SDLC• Plans projects, develop schedules and
estimates cost• Conduct meetings, delivers presentations,
write memos, reports and documentation
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Skill Required by System Analyst
• Strong technical skills, knowledge of information management concepts, tools and techniques. Solid understanding of company and business in general
• Strong communication skills
• Updated information about the technology
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Assignment - I
• Visit to the City University and prepare:– Complete organization chart– Describe the functions carried out by each unit– Show diagrammatically the Business IS also
indicate the flow of data between the subsystems
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Strategic Planning Process
• Mission Statement.– Company’s overall purpose and direction,
products, services and values.
• Goals.– That accomplish the mission. E.g. 5 year plan
• List of Objectives to achieve the Goals.– List of specific tasks within a time.
• E.g.
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IS Project Initiation
• System Request– A form should be there
• Possible reasons for system request– Improved service– Better Performance– More Information– Strong control– Reduce cost
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IS Project Initiation
• Who initiates – User request– Top management directive– Existing system – problems, Errors– IS department
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IS Project Initiation
• External factors– Change in government policies e.g. taxes– New release of version of S/W package– Competitors– Industrial and organizational relationship, IT
board want to have data of all universities, then we have to change our system to
– Advance in technology
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Evaluation of System Request
• System review committee/steering committee.
• The committee examines the feasibility of requests.
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Feasibility Study• It is the measure of how beneficial or practical the
development of IS will be to an organization• Feasibility Analysis
– It is the process by which feasibility is measured
• Categories– Operation– Technical– Economic– Schedule– Behavioral– Political
• In general PIECES (Performance, Information, Economy, Control, Efficiency, Services) is considered
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Feasibility Report - Operation
• Operational viability.– User need, management support, effective usage.
– Training, resources for training.
– Reduction of employs … what about them.
– Involvement of users.
– Operation charges?, if so compare with overall gain.
– Side affects of the new system.
– Is scheduling is reasonable.
– Look for ethical and legal issues.
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Feasibility Report - Technical
• Technically feasible.– Is need there.– Capacity of equipment– Reliable and long term planning for H/W &
S/W– Exact specifications– System be able to handle the projected growth
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Feasibility Report - Economic
• Economically desirable.– People
– H/W & S/W
– In house development / purchase
– Formal and informal training
– Licenses and fees
– Consulting expenses
– Facility cost
– other
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Criteria used Evaluation of System Request
• Reduction of cost Where, When, How and How much?
• Increase in revenue Where, When, How and How much?
• Better Result How and Are they measurable?• Will the system serve customer, organization better• How much the project life is?• Are necessary people available to proceed with?• Is the project absolutely necessary?• Tangible and Intangible factors
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Cost Benefit Analysis• Tangible Benefits
– Fewer processing errors– Increased throughput– Decreased response time– Increase sale– Reduce credit loss– Reduce expense
• Intangible Benefits– Improved customer good-well– Better service– Improved employee moral– Better decision making
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Preliminary Investigation
• Understanding the problem
• Defining scope and constraints– Constraints are conditions,limitation e.g. use
the existing H/W
• Identify the benefits– Tangible & Intangible
• Estimate the time and cost
• Report to Management
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Steps for Preliminary Investigation
• Obtain Authorization
• Identify the necessary information– Understand the problem– Define the project scope & constraints– Identify benefits– Estimate the time and cost– Report to management
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Steps for Preliminary Investigation
• Fact finding– Organization chart– Interview– Documents review– Observe current operation– Survey
• Analyze the information
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Steps for Preliminary Investigation
• Presentation to the management– Introduction
• Overview, who conducted the investigations…
– System request summary
– Findings
– Recommendations
– Time & Cost estimate
– Expected benefits
– Appendix
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System Analysis
• Determining Requirements
• Analyzing Requirements
• Evaluating Alternatives and Strategies
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Sample Question in the Phases
• Requirements Determination– What is done?
– Where is it done?
– When is it done?
– Who does it?
– How is it done?
– Why is it done?
– Why is it done there?
– Why is it done then?
– Why does the person do it?
– Why is done this way?
• Requirement Analysis– What should be done?
– Where should it be done?
– When should be done?
– Who should do it?
– How should it be done?
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System Requirements
• The features that must be included in an IS to satisfy business requirements and acceptable to users.– It identifies the characteristics of the new
system– It serves as benchmark to measure the
acceptability of the finished system
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Categories of System Requirements
• Output– Fee Slip containing StudentId,…– Income and expenditure statement should be
printed containing…
• Input– Admission form containing DATA should be
submitted at the time of admission
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Categories of System Requirements
• Processes– Fee system, Examination system
• Timing– Fee system to print Fee Slip on the last day of
each month– Accounting System should produce daily
Income and Expenditure statement
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Categories of System Requirements
• Control– Accounting System may only be used by the
Accountant only– The VC can give Fee rebate to a student
• Volume, Size and Frequencies– OPD, Current No. of customers and Projected– PakNet – No. of Users now, Expected and
complaint calls
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Fact Finding – 1- Interview (Process)
• Determine the people to interview– Select from organization chart (OC)– Consider informal structures – some persons
has more knowledge than depicted in OC– Specify the persons for his function
• Objective for the Interview– Depends on the role of the person– General area to be discussed
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1- Interview
• Preparation for Interview– Creating a list of questioner
• Open-Ended Questions
• Closed-Ended Question
• Range of Responses Questions– In which choice are given
– Order the questions– At the end a general open-ended question
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1- Interview
• Conduct the Interview– Introduction of self, project and objective of
the interview– Ask question in order– Listen carefully– Keep on noting the points– Establish good rapport(relationship)
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1- Interview• Document the Interview
– Audio recording but it can• Nervous the interviewee to respond• Be difficult to locate important passages specially on long tapes• be costly
– Note taking– Don’t write every thing the person says– After the end of interview sit a side and document it– Send it for addition or correction
• Evaluate the Interview– Identify biasness– Inexperience answers
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Structures of Interview• Pyramid Structure
– Starting from specific question and ending with general ones• It is suggested where you interviewee needs warm-up
• Funnel Structure– Starting from general questions and ending with specific ones
• It is useful in situation if the interviewee is emotional about the topic and needs freedom for expression
• Diamond-Shaped Structure– It is the combination of the Pyramid and Funnel structure– Starting from specific questions, general questions in the middle
and ending on specific ones
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Advantages of Interview• It gives an opportunity to know the areas which were not
covered in preparation• It gives an opportunity to validate the information already
gathered• Most people enjoy interview regardless of the subject so
their cooperation in a study may help in understanding• It gives an opportunity to know about complex system but
also the underlying sentiments• Disadvantages of Interview
– Time consuming– Highly depends on the systems analyst’s human relations skills– Interviewing may be impractical due to the location of
interviewees
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Guidelines for Communication during Interview
• Approach the session with positive attitude• Set the other person at ease
– Presenting a cheerful attitude• Listening• Don’t assume things• Body language• Proxemics
– The relationship between people and space• Intimate zoon closer than 1.5 feet• Personal zoon from 1.5 to 4 feet• Social zoon from 4 to 12 feet• Public zoon beyond 12 feet
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2 – Document Review
• Existing reports
• Manuals
• Forms
• Reports
e.g. Prospectus of CUSIT, Others rules and regulation books
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3 - Observation
• E.g. How an OPD is conducted, Admission.
• Plan what to observe
• Prepare a chick list of the specific tasks you want to observe– E.g. Student Coordinator,Fee System and
Registrar office
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3 - Observation
• Ask questions• Observe all steps in process cycle and note output from
each procedural step• Examine each relevant form, record and report and
determine the purpose of each item• Consider each system who works in the system and
question:– What information is generated– What toots are used in its process e.g. Prospectus
• Talk to the pople who are receiving the report –staisfied –Yes/No - Why
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4 - Questioner
• Workload, Reports received, Volumes of Transaction
• Anonymity
• Guidelines– Keep the questionnaire brief and user-friendly– Provide clear instructions for the users– Arrange the questions in logical order
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4 - Questioner
– Phrase questions to avoid misunderstandings
– Don’t include questions that lead clues to expected answers
– Limit the use of open ended questions
– Limit the use of questions that lead to raise concern about job security or other negative issues
– Include comments at the end
– Test the questionnaire on a group before finalizing
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5 - Sampling
• Collection of examples from actual documents is Sampling.
• Systematic Sampling– E.g. select every 10th customer file who filed
complaints for review
• Stratified Sampling– E.g. select every 10th customer file of each Area who
filed complaints for review
• Random Sampling
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6 - Research
• Reviewing Journals, Periodicals and Books
• Internet– Sites– Newsgroups
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JAD
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RAD
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OOAD
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Analyzing Requirements/Structure Analysis• Examining a system in terms of I/P. O/P and
Processes and to describe the requirements for a new system
• It focuses on the Flow of Data, therefore, it is also called Process Centered Technique
• Tools– DFD– Data Dictionary– Process Description
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Structured Analysis
• Logical Model– It shows What the system must do– Also called Business Model
• Physical Model– Its shows How the system will function
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Data Flow Diagram (DFD)
• It shows How data move in an Information System
• It represents Logical Model, I.e. What the system does
• It doesn’t show the Logical or Processing Steps
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DFD - Symbols
• There are several versions, the popular are Gane and Sarson AND Yourdon
• Process– Receives I/P– Produce O/P– Detail of the process is not shown in DFD, they
are documented in Process Description
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DFD - Symbols
• Data Flow– It shows the flow of Data from on part of IS to another
– The data could be Single Piece of Data of a set of data
– DFD doesn’t show structure or detail contents of data
– The Arrow Head show the the direction in which the data moves
– There is a data flow name which represents the data
– There must be a process at one end of the data flow
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Data Flow-Process Combinations (Incorrect)
• Spontaneous Generation/Miracle– Process with out I/P
• Black Hole– Process with out O/P
• Gray Hole– Process with one I/P and One O/P AND the I./P
is not sufficient to produce O/P
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Data Store
• It logical represents data storage to be used by process at later stage
• Data Store must be connected to Process
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External Entity Symbols
• It as Actor• Any entity that interact with the IS• It shows the boundaries of a System• They are also called Terminator• Source
– The External Entities that gives data to an IS
• Sink– The External Entities that receive data from an IS
• It is always connected to Process
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Context Diagram
• It shows the Scope of a System
• It is the top view of the IS
• No Data Store in it
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Context Diagram - Conventions
• Each Context Diagram must be Fit in one page
• The Process name should be the name of the IS
• Use unique names• Don’t cross lines• Uses abbreviated identifications• Use unique Reference No/ for each Process
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DFD – Elements - Process
• Process has – A number
– A Name (Verb)
– A description
– One or more O/P
– Data flow– Usually one or more I/P
Gane & Sarson
Name
Name
DeMacro & Yourdan
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DFD – Elements – Data Flow
• Data Flow has– A Name (Noun)
– A description
– One or more connections to a process
Gane & Sarson AND DeMacro & Yourdan both
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DFD – Elements – Data Store
• Data Store has – A number
– A Name (Noun)
– A description
– One or more I/P Data Flows
– Usually one or more O/P Data Flow
Gane & Sarson
D1 Name
D1 Name
DeMacro & Yourdan
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DFD – Elements – External Entity
• External Entity has– A Name(Noun)
– A description
Gane & Sarson AND DeMacro & Yourdan both
Name
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Context Diagram
• It shows the boundaries or scope of a system• Conventions
– Each Context diagram must fit in a page
– The process name in the Context diagram should be the name of the IS
– Use unique names with in each set of symbols
– Don’t cross lines
– Use abbreviated identification
– Use unique reference no. for each process symbols
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Context Diagram
• Diagram 0– This goes deep in a process to to give information how
actually information is processed
– Also called Exploded version of Process 0, Partitioned version of Process 0, Decomposed version of Process 0
– Lower-Level Diagram• Leveling
– Drawing of a series of increasingly detailed diagrams
• Balancing
– Maintains consistency among the entire series of diagrams including I/P, O/P, Data definition and Process description
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Data Dictionary
• It is the store house of information about system’s data
• It describes the data elements
• Data element– Records or Data Structure
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Data Dictionary
• It records– Data element name or Label– Alternate names or Aliases– Type and Length– Output Format or Mask– Default Value– Prompt, Column header or Caption– Source – Where the data has come– Security – Who will use it– Responsible users– Derivation Formula– Description or Comments
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DD –Data Flows
– Data Flow name or Label– Alternate names – Abbreviation or ID– Description– Origin– Destination– Record – the group of data elements– Volume and Frequency
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DD – Data Stores
• Data Store name or Label• Alternate names • Abbreviation or ID• Description• Input data Flow• Output Data Flow• Record – The name of Data Store• Volume and Frequency
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DD - Process
• Process name or Label
• Purpose or Description
• Process No
• Input data Flow
• Output Data Flow
• Process Description
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DD – External Entities
• External Entity name
• Alternate Name
• Description
• Input data Flow
• Output Data Flow
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DD - Record
• Record name
• Alternate Name
• Definition Description
• Record contents or composition – PK etc
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DD - Reports
• Alphabetical list of data elements
• Department-wise data elements
• Detail reports showing the characteristics of record etc
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Criteria for selection of:Criteria Structure
d EnglishDecision
TableDecision
Tree
Determining Condition & Action
2nd Best 3rd Best Best
Transforming Conditions & Actions
Best 3rd Best Best
Checking Consistency & Completeness
3rd Best Best Best
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Evaluating Alternatives & Strategies (EAS)
• It concentrates– Software alternatives– Consideration of various system development
approaches and techniques– Preparation System Requirements Document– Planning of of the transition to the next phase
of SDLC
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Selecting best Alternatives
• Gathering a set of alternatives
• Selecting the most likely to result in the desired IS
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Design Strategy
• It is an approach to developing the system. It includes:– Software– Hardware– People– Procedures– Data
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Evaluating Software Alternates
• In House Development• Satisfy unique requirement• Minimum changes in
business procedures and policy
• Meet constraints of the existing system
• Meet constraints of the existing technology
• Develop internal resources and capability
• Purchase of S/W• Lower cost• Requires less time to
implement• Proven reliability and
performance • Implemented by other
companies• Requires less technical
development staff future upgrades provided by vendor
100
Evaluating Software Alternates
• Customizing Software Packages– The software that gives the facility to be
customized e.g. MS Money, Peach Tree…– Negotiate directly with the S/W vendor– Purchase S/W along with source code and make
changes
101
Other S/W Alternates
• Outsourcing– E.g. Photostat machine in the City University
• End-User System– Purchasing Application S/W that are user friendly and
let user to work in easily. E.g. MS Words…
• Enterprise Computing– The S/W that satisfy the requirement of the whole
company.– Data is centralized and available the user who need
e.g. Clint/Server applications
102
Steps in Evaluating & Purchasing S/W Packages
• Evaluating the IS Requirements– Identify the key features of the system
• In payroll at Pakistan Level there may be different types of taxes in provincial government
– Estimate the volume and future growth– Specify any H/W constraints– Prepare a request for proposal or quotation
• Request for Quotation• Request for Proposal
103
Steps in Evaluating & Purchasing S/W Packages
• Identify Potential S/W vendors– RFP will help here also
• Evaluating S/W Package Alternatives– Brochures, Clientage List…
• Make the purchase– S/W License, Lease Agreement– Maintenance Agreement– Trainings
• Install the S/W package
104
Hardware Alternatives
• Request for Quotation
• Request for Proposal
• Turnkey System
• Site Preparation
• UPS
• Networking
105
System Requirements Document
• It contains– The requirement of the new system– The alternatives that were considered– Recommendation to the management
• The document is presented to the Management for approval to move to another SDLC phase
106
Output Design
• Logical Design– It defines the logical functions and and
relationships amongst the components– It is meant to show WHAT the system would
do
• Physical Design– It is a plan for actual implementation of a
system– It concerns HOW the system will do
107
System Design Activities
• Review the system requirements
• Design the system– Design of output– Design of input– Design of files and database– Design the system architecture
108
Guidelines for System Design
• User Considerations– Consider points where users interact with the system– Anticipate future needs of the user and organization
• E.g. Separate tables for codes
• Data Considerations– Enter data where and when it occurs– Verify data where it is input– Use automated data entry methods whenever possible
• Hand Hold Scanners
– Report every instance of entry and change to data• E.g. Log files
– Enter data only once
109
Guidelines for System Design
• Processing Considerations– Use a modular design
• E.g. Based on DFD Processes
– Design independent modules that performs a single function
110
Designing of Codes
• Letters or numbers or mixed representing data– Sequence code
• E.g. starting from 1 and go on• it doesn’t show any other information
– Block sequence code• E.g. CS-100, CS-101
– Classification code• E.g. EDU, CS for departemnts
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• Alphabetical code– They are abbreviations – E.g. psh for Peshawar
• Mnemonic code– Combination of letters and symbols e.g.
• Significant digit code– Digits used to distinguish groups– E.g. 03-0202-0010
• Derivative code– Combination of data from different attributes– E.g. 1st letter of name, 1st letter from district and last name
112
• Cipher code– CAMPGROUND=123456780– Now in a shop the sale need not to look the price on each item
rather he would read the code and understand about the price– E.g. grand means Rs.562.94
• Action code– E.g. D for delete
• Self checking code– 1306-6
• 1x1+3x2+0x3+2x4=15 i.e. 1+5=6 here 6 matches the 6 above therefore the code is ok
113
Developing codes
• Concise – Short
• Expansion• Stable
– Cu-0166, 03-Sring-0166, 02-0202-0166• Unique• Sortable• Avoid confusion• Meaningful• Single purpose• consistant
114
Introduction to O/P Design
• Types of O/P– Printer– Screen– Plotter– Audio– E-mail– Links to web pages– Automated facsimile system– Computer O/P microfilm
• Record information as image
– Other specialized devices• ATM, POST
115
Designing Printing/Screen/Graphical Reports
• Reports– Report Header– Page Header– Group Header– Detail– Group Footer– Page Footer– Report Footer
• Detail Reports• Exception Reports• Summary Reports
116
Report Volume and Time Calculation
• Types of Printer
• Print Volume Calculation
117
O/P Control
• Integrity– Correctness– Completeness
• Security– Rights for individuals/groups
118
Design Tools
• Report generators
• Screen generators
119
Input Design
• I/P Design Objectives– To select the most suitable I/P media and
method– To develop efficient I/P procedure– To reduce I/P volume– To reduce I/P error
120
I/P Objectives
• To select the most suitable I/P media and method– Batch I/P – Online I/P
• POST
• ATM
• Magnetic ID for Employees for entrance
• Bar Code reader
121
• To develop efficient I/P procedure– E.g compare the procedure of Admission and
Registration system of CU– Reduce I/P Volume
• I/P necessary data
• Do not enter data that can be retrieved from system
• Do not enter constant data
• Use codes
122
• Reduce I/P Errors– Sequence Error
• If registration is placed in sequence
– Existence checks• If a record is entered with blank value the system
should stop there
– Data type check– Range check
• Marks>100
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– Reasonableness check• E.g. an allowance of Rs.2000 given for class 4 employee
– Validity checks• Referential integrity
– Combinational checks• E.g. if a student has got 3.33 GPA that the scholarship field is
updated
– Batch Control• I/P first the No. of entries and then start entering data
124
Tasks in I/P Design• Design Data Entry I/P Procedures• Design Source Documents from which data is to be
captured – External or Internal i.e to be used in office or go out– Space – Vertical & Horizontally, Line Spacing, Font
– Understandable
– Data Entry Positions should be indicated – boxes
– Keeping form headers & grouping concepts
– Attractive
125
Tasks in I/P Design
• Design I/P Data record– The entry sequence / order– No. of records on a screen
• Design Data Entry Screen– Attractive– Meaningful logical information– Consistence – Titles…etc– Messages– Special Effects – Color Blinking– Feed Back– In the documentation the Screen Layout should be
taken
126
Guide Lines for Data Entry Screens• Restrict user access to screen location till entering
data• Descriptive Captions, Tool tips• Predefined Format – I/P Masks• Ending Key Stroke • Characters not required should not be entered - /,
leading or Trailing zeros in integers• Display default values• Combo/list boxes• Provide way to close screen with saving a record
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Guide Lines for Data Entry Screens
• Record confirmation before saving
• Design the screen that match the document
• Allow user to Add/Delete/Change record
• Allow user to Search record
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• Process Control Screen Design– Menu Screens
• Levels of Menu
– Prompt Screen• E.g Enter Parameter value
– Question Answer Screen• E.g Want to Print (Y/N)
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• Design of Graphical Interface– Menus– Dialog box– Popup Menus– Toolbars– Help Screen
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Input Control
• It is to ensure that I/P data is correct, complete and secure
• A company must have procedure for handling source documents to avoid data loss
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System Architecture
• Standalone Vs Multiuser access• Processing Methods
– Online Processing– Batch Processing– Centralize Processing
• Mainframes and Terminals
– Distributed Processing• Data Communication Network consists of terminals,
computers and other equipments– Where to perform system processing– Where to store data
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LAN and WAN
• Network – Allows H/W, S/W and data resources to be shared
• Topology– The way a Network is configured is Topology
• Nodes– Individual location on the Network is Node
• Protocol– A set of standards that governs data transmission
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Arrangement Patterns of LAN/wan
• Hierarchical Network• Bus Network
– A single communication path connects the terminals, Mainframes and Minis
• Star Network– A central computer with many computers connected
• Ring Network– A circles of computers communication with each other
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Client/Server System
• It divides processing between clients and server
• Clients handles user interface and Server provides data access
• It reduces load and improve response
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Processing Functions
• Data I/P and validation– Suspense files
• Error transactions files
• Updating– File maintenance
• Sorting– Specially in file based system
• Reporting
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Processing Support• Backup & Recovery
– History/Journals
• File Retention– Length of time a file needed to be stored
• Restart– Incase of program error – the previous copy is restored
back– Check points – Messages etc
• Starting up Processing– If a new system is built and data from the current
system is to be migrated that all required data be shifted
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Software Design
• It means which program will do which function
• Program Required– For each function Identify program
• Use separate programs for updates
– Validation programs– Reduce No. of reports– Identify any special processing programs
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Program Documentation
• Program Identification
• Purpose of Program
• Files
• Process Requirement – Process Description
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System Design Specification
• Management Summary– Overview of the project– Current status– schedule– Overall benefits of the new system– Costs for the remaining phase
• System components detail– Complete design of the system
• Programs, I/P, O/P Database etc• Backup system
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System Design Specification
• Environment requirements– H/W, S/W and security – Processing schedules
• Implementation requirements– Startup processing requirements – data conversion etc– Training– SW testing plan on actual data
• Time and cost estimates– Cost of the development phase
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Application Development
• Planning– Top down approach
• Module
– Review system design• Process description, DFDs• Preparation flow charts, pseudo codes…
• Coding• Testing
• Module-wise• Link testing• System testing
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Application Development• Documentation
– Program documentation– System documentation– Operation documentation– User documentation
• System overview • Source document contents• Menu and entry screens options• Information about reports• Security & audit trial information• Responsibility of specific I/Ps• Examples of exceptions and error situation• FAQ• Explanation how to get help
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Installation and Evaluation• Prepare an operational environment • Install the new system• Provide user training
– User Training• System overview• Key terms• Startup and shutdown• Menus• Icons and shortcuts• Help• Troubleshooting quite• Handling emergencies
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Installation and Evaluation
• Managers– Project origin– Cost-benefits analysis– Support for business goals– Handling system changes– Requesting enhancements– User training
• IS Staff– Project history and justification– System Architecture– System documentation– Vendor support– Logging and resolving problems– Technical training– User and management training
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Installation and Evaluation
• Vendor Training– In case of purchase of S/W or H/W
• In-house training– Guide lines
» Train people in groups
» Select effective place for training
» Provide for learning by hearing, seeing and doing
» Prepare training manual
» Develop interactive tutorials and training tools
» Rely on previous trainees
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Installation and Evaluation
• Perform file conversion and system changeover– Importing data in the new system– Direct change– Parallel change– Pilot change– Phased change
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Installation and Evaluation
• Carry out post-implementation evaluation of the system– Accuracy– User satisfaction– Accuracy in security measures– H/W efficiency– Effectiveness of Database implementation– Performance of IS team– Completeness and quality documentation– Quality and effectiveness of training– Accuracy of cost-benefits estimates
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Installation and Evaluation
• Present final report to management– Final version of all system documents– Planned modifications and enhancements to the
system that have been identified– A recap of all system development cost and
benefits– A comparison on actual cost and schedules to the
original estimates– The post implementation evaluation, if performed
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System Operation & Support• It starts after the system is operational• System Analyst’s TWO important tasks
– Support Activities• User training• information centers
– Maintenance Activities• Corrective Maintenance
– Diagnosis and correction of errors in an operational system
• Adaptive Maintenance– Adding enhancements to an operational system
• Perfective Maintenance– Changes to make it more efficient, reliable and maintainable