SYSTEM ENGINEERING

Objectives

System concepts: Model, Types and Classes System Control and its use in MIS Handling of System Complexity Post Implementation System Problems Entropy, Negative Entropy Audit Trail Application Need for Systems Analysis Systems Analysis Design Integrated MIS System Development Models

2

System Concepts

System is defined as a set of elements arranged in an orderly manner to accomplish an objective

System is not a randomly arranged set It is arranged with some logic governed by

rules, regulations, principles and policies A clear statement of objectives brings a

precision and an order into the selection of elements and their arrangement in the system

Any disorder would create a disturbance in the system

3

Parts of a System

Input ofData

Resources

Input ofData

Resources

Processing Data

Processing Data

Output ofInformation

Products

Output ofInformation

Products

Control of System PerformanceControl of System Performance

Storage of Data ResourcesStorage of Data Resources

4

Business as a System

A business is an organizational system where economic resources (input) are transformed by various organization processes (processing) into goods and services (output).

Information systems provide information (feedback) on the operations of the system to management for the direction and maintenance of the system (control), as it exchanges inputs and outputs with its environment.

5

Contd.,

A system may have single input and multiple outputs or several inputs and multiple objectives

The choice of inputs and processing methodology is governed by the objectives set for the system

All the systems operate in an environment The environment may influence the system in

its design and performance The understanding of boundaries of the system

is essential to bring a clarity in explaining the system components and their arrangement.

6

Generalized Model of a System

InputProce

ssOutp

ut

Filter

ENVIRONMENT

7

Contd.,

The environment influences the choice of inputs, the method of processing, and the nature and the contents of the outputs

Most of the failures of the systems lie in the area of selection of the inputs and the processes, and not providing appropriate filtering systems.

8

Systems Control

The achievement of the objectives through system control becomes the integral part of the system design

The control calls for a measurement of the output in some terms

The device that measures the output is called a sensor

The next step is to set the standard or norm of the output as an index of the system performance.

9

Contd.,

The sensor measures the output and compares it with the standard

If the measured output compares well with the standard, the system provides a feedback to the system to stop the operations

The process of comparison of a measured output with the standard is done by a unit called comparison unit

The mechanism, which provides a signal to the system, about the quality of performance, favorable or adverse, is called a feedback mechanism.

10

Contd.,

It is necessary to provide an in-built mechanism which will decide, based on the feedback to stop, regulate or continue the system operations, called corrective unit

The corrective unit, in its performance, will act on inputs and processes to bring the system under control

The process of measuring the output, comparing with the standard, sending the signal to the corrective unit and the corrective unit acting upon it, is called a control.

11

System Concepts

ManufacturingProcess

Input ofRaw Materials

Output ofFinished Products

Environment

Other Systems

Control byManagement

ControlSignals

ControlSignals

FeedbackSignals

FeedbackSignals

System Boundary

12

Control

The role of control is to regulate the system operations and performance, and keep it in an equilibrium condition. It is the heart and brain of the system

The control could either be internal or external to the system

The concept of a control system model is applied to data processing where all the features are used in the programs of the data processing.

13

Control System Model

Input Process Output

Sensor

Comparison Unit

Standard

Corrective Unit

Channels of Feedback

14

Control System Model for Data Processing

15

Input DataUse of

Program for Processing

Computed Result

Summary of Results

Compared Results vs.

Target

Target Results

Decision Control Feedback – Positive or

negative

Change the

Program if

necessary

MIS Model of Quality Assurance

16

Upper & lower limits

Weight control chart

Quality Assurance Manager

Weight, Size, Color,

Qty

Manufacturing Process

Raw Material

Data on Measures of

quality

Analysis of quality data

Designated measures of

quality

Tools to compare

Quality control limits

Corrective unit Feedback through

plotting of weights

Action to correct the process of

manufacturing

WeightOne

measure of quality

MIS and Support to BusinessSystem

Components

Business System MIS

Inputs Raw materials, plant and machinery, manufacturing, selling, accounting

Data from transactions of purchase, production and sales, receipts & payments

Process Purchasing, manufacturing, selling, accounting

Transaction processing and data processing

Outputs Quantity of production, sales, stock, income and profit

Computation of production in numbers, sales in value, stocks in weight, income and profit in rupees

Sensor Profit Income less assigned cost

Comparison unit

Expectation of profit vs. actual profit

Algebraic comparison module to compare income vs. budgeted income profit vs. budgeted profit

Standard Profit, Target Budgeted profits of various products

Feedback Balance Sheet and Analysis

Exception reports after analysis showing products earning profit below the budget

Corrective unit

Managing Director, Business decisions

Marketing Manager. Pricing, advertising and promoting decisions

17

Types of System

A system is defined and determined by its boundaries and objectives

In a serial subsystem processing, the entire output of a subsystem is the input to the next subsystem and so on

In the matrix arrangement the different outputs go to different sub-systems

A subsystem receives more than one input from other subsystems.

18

Subsystems in Serial Order19

Subsystems Operating in Matrix Order

20

Contd.,

Black Box System: If the process of input transformation is not visible and understandable then it is a black box system

Deterministic: A system is called deterministic when the inputs, the process and the outputs are known with certainty. Example: Accounting system

Probabilistic: When the output can only be predicted in probabilistic terms. Example: Demand forecast

21

Contd.,

Closed system: If a system is functioning in isolation from the environment, then the system does not have any exchange with the environment nor it is influenced by the environmental changes. Example: Accounting systems like cash books, stocks, etc.

Open system: If the system has exchange with environment and is influenced by the environment then it is called open system

22

Handling System Complexity Factorization: The process of putting the

subsystems in the hierarchical order to provide a structural view showing the development path to the designer

Simplification: The process of clustering the subsystems together

Handling all the subsystems together with their interconnections is difficult

Each interconnection acts as a channel for the input-output communication.

23

Method of Simplification

1. Identify the subsystems which have to be together for the functional ‘cohesion’

2. Form a cluster of these subsystems and identify interconnections in this cluster

3. Form clusters of the remaining subsystems

4. Connect the clusters with an interface

24

Materials Management System The materials management can be

subdivided as follows as shown in Step 1:A. Procurement SystemB. Purchase order follow up systemC. Receipts accounting systemD. Material requirement planning systemE. Materials issue requisition systemF. Bill passing and payment systemG. Inventory control system.

25

Subsystems with Interconnections Step 2: MM is divided in seven systems from A to G

and their interconnections are identified as follows:

A C FD

GEB

26

Formation on Clusters The subsystems can be clustered in number of

ways In the following figure it is clustered based on

the managerial function such as purchase, accounting and planning

A

B

F

C

E

D

G

Cluster-1 Purchase Function

Cluster-2 Stock

Accounting Function

Cluster-3 Materials

Planning & Control

Function

27

Contd.,

Clustering the subsystems by operating departments – A, B, C and E will be a cluster, F will the second cluster and D and G will be the third cluster

When the subsystems are clustered together and connected, the designer faces the problem of tight connectivity

The solution is to decouple the clusters from each other by providing interface between the clusters

The process of decoupling makes the two clusters operationally independent of each other.

28

Decoupling of Subsystems

The interface provides an operational independence by allowing the other subsystem to operate on the limited information already stored

A

B

F

C

E

D

G

Purchase

Information

Stock Informat

ion

Interface Interface

29

Contd.,

The benefits of the operational independence are not without the extra cost of providing an interface because as a subsystem, the interface also needs to be designed, keeping in view the specific needs of the interfaced subsystems

The use of decoupling mechanism should be considered as the last alternative for reducing the rigid requirements of a communication exchange.

30

System Efficiency and Effectiveness

Efficiency indicates the manner in which the inputs are used by the system, i.e., the system uses inputs in a right way

If the input-output ratio is adverse, we say that the system is inefficient though it produces desired output

Effectiveness is the measure for deciding whether the system provides the desired output or not, i.e., producing the right output in terms of quantity & quality

Effectiveness is a measure of the goodness of the output and efficiency is a measure of the productivity.

31

Post Implementation Problems in a System

When systems are allowed to run for some time, they tend to become disorganized, resulting into system inefficiency

The process of decay and its cause is called entropy

Negative entropy: Course of action to arrest the decay

The process of providing negative entropy is called system maintenance.

32

Steps of Negative Entropy

a) A periodical review of the systemb) User meetings to assess the current

utility of the system and the level of satisfaction

c) Subjecting the system to an audit check through the test data

d) Running the system under audit traile) Bringing out system modifications.

33

Examples of Negative Entropy

System Indications of entropy

Negative entropy

Human body

Loss of weight, headache

Medical check-up and prescribed diet and medicines

Computer

System halts, read and write errors

Preventive maintenance and replacement of sensitive components

Data Processing

Errors and omissions in the data on increase

Review and introduction of the streamlined procedure

Information Processing

Decline in the utility and satisfaction, changed information needs

Resetting the goals of information system. Add revised information needs and modify the information system.

34

Problems of System Decay

Business environmental changes – modification to business goals and objectives

Information needs of the managers changes Changes may call for more hardware and

software Additional application programs need to be

written The efficiency of the information system is

high if these changes are easily accommodated in a short time.

35

Contd.,

The keys to handle the post implementation problems are:a) The core system design must be

comprehensive and flexible to undergo a quick change

b) The associated peripheral systems should be built with a flexible design

36

Classes of Systems

Data Processing System (DPS) Transaction Processing System (TPS) Application Processing System (APS) Business Function Processing System

(BPS) Integrated Information Processing System

(IPS)

37

Data Processing System

DPS is designed to capture, collect or enter the data to process in a certain specified manner to achieve the following: Data is complete, correct and valid from all

aspects Next, Data will be processed and organized DPS may have an algorithm using one or

more inputs and may produce one or more outputs

38

Model of DPS

System of capture, collect, enter

System of scrutiny, checking, validating

System of results

processing

Reports

Master Files

Results record file(s)

Query processin

gDisplay

39

Transaction Processing System TPS is designed to handle a transaction

between parties The parties could be two or more and

have a designated role in TPS TPS uses data files, master files,

transaction records and processes the data

TPS output is a transaction in itself and updating the various other records

40

Model of TPS

Transaction Data

files

Master File(s)

Transaction

Process algorithm

Transaction Processing systems for accuracy,

completeness, consistency, validity and decision for

acceptance or rejection

Processed

transaction file(s)

and Records

Display

Output

Report or

Document

Query processin

g

41

Application Processing System APS is built over DPSs and TPSs APS uses files created by DPS and TPSs, and

applies application-processing rules to execute the application

APS may have an output as a document, a report or a set of rules required for processing

Example: In a Billing system, the following output files are used Customer order acknowledgement Product delivery to customer Delivery acknowledgement and acceptance by the

customer

42

Model of APS

Processed

Transaction files

Master File(s)

Application

Processing rules

Application Processing systems for verification, checking,

selecting rules, computing

formulae and formatting

Application output

file(s) and

Records

Display

Output

Report or

Document

Query processin

g

43

Business Function Processing System BPS deals with business functions BPS aids in business function processing and

helps management in decision-making BPS focuses more through information

support for management of business function It brings out more MIS reports for business

function management such as Sales, production, materials..

Business function is built on several business process applications

Business system uses relevant APS and TPS outputs for processing the system results.

44

Model of BPS

Application

process system output files

Transaction output

File(s)

System Processin

g rules

System processing after

checking file consistency,

validity

System Result file(s)

Display

Future MIS

Reports

Query processin

g

Summary of

Results file for DSS

45

Integrated Information Processing System IPS is an integrated information processing

system for producing information supporting top management’s decision-making

IPS sits on the top of the rest of the systems IPS draws its input from these systems, and

applies information processing rules to bring out an output

IPS meets requirement in the area of planning, budgeting and strategic control

Example: Project planning, Capital budgeting, manufacturing planning, preparing year-end balance sheet schedules and reports.

46

Model of IPS

TPS Output

files

Results Databas

e

APS Output

files

Function Database

s and Metadata

Knowledge

databases

IP rulesModels

AlgorithmsUse of

informationProcess tools

Reports

Spread sheet

Application (SSA)

Executive Information System

(EIS)

Data Warehousing System

(DWH)

Data Mining System (DMS)

Knowledge Process System (KPS)

47

General Model of MIS

MIS is an arrangement of data processing and information systems in an orderly manner to support the management in achieving the business objectives

MIS performs on the principle of feedback and control by exception

MIS is designed to provide the information which is exceptional in nature from the point of view of business

MIS is an open system interfacing continuously with the internal and the external environment.

48

Contd.,

MIS is a hierarchical structure, subdivided into smaller subsystems

The complexity of the MIS is handled by simplifying the subsystem structure decoupling the two subsystem clusters

A good MIS is founded on the in-depth system analysis of the business and management processes

The elements of the MIS are the computer hardware, the communication channels, the software and the software tools, the development plan and a well-defined measurable objective.

49

General Model of MIS

SOURCING SYSTEMS

BIS, DWH, DMS, SPAs

DATA PROCESSING

TRANSACTION PROCESSING

APPLICATION PROCESSING

SYSTEMS PROCESSING

INTEGRATION OF SYSTEMS

PRODUCTION SYSTEMS

EXPERT AND ARTIFICIAL INTELLIGENCE SYSTEM

QUERY PROCESSING

EXCEPTION REPORTING

DATABASE, KNOWLEDGE BASE

DECISION SUPPORT SYSTEMS

OPERATION RESEARCH AND APPLICATION

PACKAGES

PROCESSIN

G

MIS MODE

L

50

The Need for System Analysis System Objective System Boundaries – Define the scope

and coverage of the system System Importance Nature of the System – closed, open,

deterministic, probabilistic Role of the system as an interface Participation of users Understanding of resource needs Assessment of feasibility.

51

Steps in System Analysis & Design

52

Contd.,

Steps Elaboration Explanation

Conceptual system design

Determine the inputs, process and outputs, and design a conceptual mode

Conceptualization is necessary to understand the system process

Detailing the system design

Draw the document flowcharts and the DFD, the data and system hierarchy diagrams, the data and information vs. its users mapping table

Helps in bringing a clarity in the dataflow. The responsibility centers and the process centers are identified.

Structuring the system design

Break the system into its hierarchical structure

Helps in understanding the dataflow from one level to the other and the processes carried out at each level

Conceptual model of computer system

Define step by step the usage of files, processes and interface. Define the data structures and draw DFDs

Helps to put down the data processing flow in the computerized system. Draw the computer system charts.

Break the system in program modules

Make a physical conversion of the system into the program structures in a logical order

Modules will be data entry, data validation, data processing, reporting and storing

53

Contd.,

Steps Elaboration Explanation

Develop the test data test cases for checking the system ability

Test the modules and the integrity of the system in terms of input vs. output. Plan white box and black box testing.

Confirms whether the system design is satisfactory. Suggest the modifications.

Install the system

Install on the hardware Install, test and run the system before the user is exposed in a live mode.

Implementation

Train the personnel. Run the system in parallel. Prepare a system manual.

Helps to identify the user problems and provide solutions

Review the maintenance

Review the system through audit trail and test data, use change management system for modifications.

Helps to maintain the system quality and the quality of information through modifications, if necessary.

54

System Analysis of the Existing System Analysis helps in achieving the following:

Understanding the existing system Understanding the objectives achieved by

the existing system Evaluating the system for computerization

and its placement in the total MIS design Knowing whether the system is feasible

technically and operationally Are the information fully justified? If so, is the cost of the system design

justified to increase the value of information?

55

Procedure of Analyzing the Existing System1. Carry out the analysis of the system at a

place where the system is functioning2. Note down the key personnel in the

system besides the HOD3. Spend some time with the operating

personnel and observe the system to understand the finer details of the system

4. Define the scope of the system and its objective

5. Collect all the documents which are raised in the system.

56

Contd.,

6. Collect separately the outputs which as statements, reports, memos, etc

7. Make a list of rules, formulae, guidelines, policies..

8. Note down the check points and the controls used in the system to ensure that dataflow is complete

9. Study the flow of data in the system in units, summary and aggregates from document to document from one stage to another

10. Make a small system note as a base document and discuss with respective HOD.

57

Contd.,

11. Examine whether the achievement of the system’s objectives is feasible in the present system

12. If there are problems in the feasibility of implementation, then examine whether the present system can be modified

13. Draw a revised system flowchart to indicate how the system runs the major steps of processing the information

14. Discuss the flowchart with the personnel operating the system

58

Contd.,

15. Make a list of the outputs containing information

16. Analyze the requirements of the information and reports from the utility point of view

17. Compare the costs of the old and the new system and the benefits offered

18. Obtain approval of the new system 19. Write a system manual

59

System Analysis of a New Requirement1. Definition of the system and its

objective2. Development of the system (Analysis-

Design-Programming)3. Installation of the system4. Operations of the system5. Review and evaluation

60

Contd.,61

Contd.,62

Contd.,

Stages in development cycle

Steps in each stage Purpose

Installation of the system and testing

The system is tested and installed on the hardware for implementation. Switching over to computer system after thorough operational testing

The step ensures that the operational problems are resolved and the user gets live experience of the system. Modifications, if any, are carried out. Checks and controls are ensured through testing and the parallel runs.

Operations of the system

The system is operated in full course and existing systems (if any) discontinued

The user confidence is built and the designer simultaneously evaluates the performance of the computer system

Review and Evaluation

A review is taken whether the system objectives are being met with and what are the problems in the smooth running. Steps are taken to resolve them

This is an audit by the designer for improvement through test data and audit trail.

63

System Development Model

Waterfall Model: This model describes a development method that is linear and sequential.

Waterfall development has distinct goals for each phase of development.

Once a phase of development is completed, the development proceeds to the next phase and there is no turning back.

64

65

SDLC Phases

Advantages of Waterfall Model It allows for departmentalization and

managerial control. A schedule can be set with deadlines for each

stage of development and a product can proceed through the development process.

Development moves from concept, through design, implementation, testing, installation, troubleshooting, and ends up at operation and maintenance.

Each phase of development proceeds in strict order, without any overlapping or iterative steps.

66

Disadvantages of Waterfall Model It does not allow for much reflection or

revision. Once an application is in the testing

stage, it is very difficult to go back and change something that was not well-thought out in the concept stage.

67

Spiral Model

The spiral model, also known as the spiral lifecycle model

This model of development combines the features of the prototyping model and the waterfall model

The spiral model is favored for large, expensive, and complicated projects.

68

Spiral Model69

Steps in Spiral Model

1. The new system requirements are defined in as much detail as possible. This usually involves interviewing a number of users representing all the external or internal users and other aspects of the existing system.

2. A preliminary design is created for the new system.

3. A first prototype of the new system is constructed from the preliminary design. This is usually a scaled-down system, and represents an approximation of the characteristics of the final product.

70

Contd.,

4. A second prototype is evolved by a fourfold procedure: (1) evaluating the first prototype in terms of its strengths, weaknesses, and risks; (2) defining the requirements of the second prototype; (3) planning and designing the second prototype; (4) constructing and testing the second prototype.

5. At the customer's option, the entire project can be aborted if the risk is deemed too great. Risk factors might involve development cost overruns, operating-cost miscalculation, or any other factor that could, in the customer's judgment, result in a less-than-satisfactory final product.

71

Contd.,

6. The existing prototype is evaluated in the same manner as was the previous prototype, and, if necessary, another prototype is developed from it according to the fourfold procedure outlined above.

7. The preceding steps are iterated until the customer is satisfied that the refined prototype represents the final product desired.

8. The final system is constructed, based on the refined prototype.

9. The final system is thoroughly evaluated and tested. Routine maintenance is carried out on a continuing basis to prevent large-scale failures and to minimize downtime.

72

Measure of a Good System

The definition of a good system varies with the system’s environment The performance may be the key measure The ability to change fast may be the key

measure The user friendliness could be a measure

In all cases, the correctness of the result is a common measure, making them reliable and dependable for the business operations.

73

Contd.,

The speed and response are the performance measures in case of large volume transaction-based systems

The flexible design is a measure of performance where the system needs continuous modifications

In complex systems, the user friendliness and the ease of operations become the measure

A good system design considers the environment and the users, and incorporates all the needs and expectations.

74

The System Development Methods

Traditional software development methods: Deal with functions and data separately Structured Systems Analysis and Design (SSAD) -

Ross Structured Analysis and Structure Design (SASD) –

Yourdon A system developed with SSAD is easy to

understand but difficult to maintain The reason is that for each function and its

behavior the data structure id defined The functionality behaves correctly under the

conditions of the rigid data definition and structure.

75

Contd.,

In real life the data format changes, calling for a change in the programs to meet the revised format and its processing

The length of the program and its complexity increases due to first checking the data condition, and then moving the control to an appropriate command

In SSAD approach, the user should have two views: The first view on the data and The second on its functionality.

76

Contd.,

Object Oriented Technology (OOT) views the system and then models in terms of Object, where the function and data are defined at its lowest level

OOT views data and function as one integrated entity

In SSAD, the requirement is fulfilled through defining and associating the data for each function

In the OOT, the requirement is fulfilled through the object(s) processing, where the object itself is based on the behavior.

77

Contd.,

A good object model of the system does not require any changes at a ‘class’ or ‘super class’ level but only at the instance level

In SSAD, this would need a condition definition for recognition, then the changes in the data and process flow, further defining the output of the new requirement

In OOT, the situation is handled by creating an instance where only the computing behavior is different from the others.

78

Contd.,

The instance is created by using the principle of inheritance

Hence the change in the system and the program progress is only at the lowest level and is local, not running across the total model of the system

For a given business functionality, the objects are defined in different categories and the system design is built through the objects and is processed through object processing.

79

Contd.,

The following steps of the development are common Requirement Analysis Requirement Definition System Design – Input, Process and Output

design System Development – Structuring the

modules and Developing the modules Unit Testing Integration of the modules Integrated system testing Implementation Maintenance

80

Symbols in SSAD81

External Entity - Rules

• External people, systems and data stores

• Reside outside the system, but interact with system

• Either a) receive info from system, b) trigger system into motion, or c) provide new information to system

• e.g. Customers, managers• Not clerks or other staff who simply

move data

82

Data Store - Rules

Data StoreD1

• Internal to the system• Data at rest• Include in system if the system

processes transform the data– Store, Add, Delete, Update

• Every data store on DFD should correspond to an entity on an ERD

• Data stores can come in many forms:– Hanging file folders– Computer-based files– Notebooks

83

Data Flow - Rules

Data Flow

• Data in motion, moving from one place to another in the system– From external entity (source) to

system– From system to external entity

(sink)– From internal symbol to internal

symbol, but always either start or end at a process

84

Processes

Logical process models omit any processes that do nothing more than move or route data, thus leaving the data unchanged. Valid processes include those that:

– Perform computations (e.g., calculate grade point average) – Make decisions (determine availability of ordered products) – Sort, filter or otherwise summarize data (identify overdue

invoices)– Organize data into useful information (e.g., generate a report

or answer a question) – Trigger other processes (e.g., turn on the furnace or instruct a

robot) – Use stored data (create, read, update or delete a record)

85

Reading a DFD86

Customer Validation: Process Model

Type

Country

Size

Kind

Private

Government

Export

Small

Undertaking

USA

Large

Central

Asia

Medium

State

Europe

Reject

Reject

Reject

Reject

Accept

Accept

Accept

Accept

Accept

87

Computer System Design

The computer system design consists of five major steps: Designing the output Designing the input Processing Data specifications Procedure specifications

88

Output Design

The information as an output, can be printed, displayed or stored

The output design requires to determine the reports, the screens, the contents of the reports and the screen and the layout of the contents

Report should have an appropriate title with a period reference, date of processing and a system title

Pages should be numbered, with title repeated with the statistics such as the number of records, items…

89

Contd.,

The layout should be such that the readability from left to right and from top to bottom

Each column and row should have meaningful titles

The layout should provide sub- and grand totals Expanded form should be provided for

abbreviations and should be universal and common

Highlight the areas of concern where the attention of management is required.

90

Input Design

The guidelines for selecting the data item from the document and grouping them into record are:

Only the data items which have a current and a prospective use should be included.

The data items from a document should be grouped together and arranged in logical order of its use in processing.

The grouping of the data items should be in line with its application.

91

Processing Design

The process design deals with two types: Computing and Decision making

92

Data Specifications

The data specification is expressed in terms of length of an item in terms of characters, its nature in terms of numeric or alpha or

alphanumeric A data item may have some value and hence

it would have come conditions and validity The specifications are used for error checking,

control and processing A data item before it is accepted as an input is

checked against specifications.

93

Procedure Design

The guidelines for drawing the system flowchart are Identify the start and the end of the system Identify the inputs, in terms of the data and

the documents entering in the system, in their logical order. Determine the transaction and the master files in the system

Identify the output at each stage and decide the media for processing and storage.

94

Steps in Procedure Design

Steps Explanation Comment

Data entry of the transactions, master data

A simple data entry as per the input design specification

Provides the data entry programs for all the documents considered in the system

Data validation

The data entry is validated as per the input picture specification and control specification

Shows the errors of presence and absence of the data entity and any violation of given specifications

Transaction validation

Validates the transactions for its type and for the internal consistency

Shows the wrong type of transactions entering in the system and the mistake in the documentation of the transaction

Edit and update

The errors and new data to be updated to complete the records

Helps to correct the data at all the levels

95

Contd.,

Steps Explanation Comment

Data processing

Shows at each stage the process and the activities such as sort, merge, collate and computer. It also shows the use of files and its further use in the system

Helps to understand the step by step development of system processing

Output processing

Show whether the output is printed, displayed and stored. Shows the device on which the output is processed

Helps to understand how the output is produced.

96

MIS and the Systems Analysis The tools of the systems analysis and the

method of development enforce a discipline on the designer to follow the steps

The success of MIS lies in meeting the information needs of the various personnel in the organization

The systems analysis with its structural analysis and design approach ensures an appropriate coverage of the subsystems

The data entities and attributes are considered completely

97

Contd.,

The systems analysis begins with the output design

The systems analysis and design exercise considers testing the feasibility of the system as an important step

The system analysis is not restricted to the data-process-output. It also covers the technologies which enables the process feasible

An emerging model of the MIS is with the databases stored in the back-end servers and the front-end users having access to it.

98

Flowchart symbols

Start/End: The terminator symbol marks the starting or ending point of the system. It usually contains the word "Start" or "End."

Action or Process: A box can represent a single step ("add two cups of flour"), or and entire sub-process ("make bread") within a larger process.

Document: A printed document or report.

Decision: A decision or branching point. Lines representing different decisions emerge from different points of the diamond.

Input / Output: Represents material or information entering or leaving the system, such as customer order (input) or a product (output).Connector: Indicates that the flow continues where a matching symbol (containing the same letter) has been placed.

Flow Line: Lines indicate the sequence of steps and the direction of flow.

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Contd.,

Delay: Indicates a delay in the process.

Merge: Indicates a step where two or more sub-lists or sub-processes become one.

Collate: Indicates a step that orders information into a standard format.

Sort: Indicates a step that organizes a list of items into a sequence or sets based on some pre-determined criteria.

Subroutine: Indicates a sequence of actions that perform a specific task embedded within a larger process. This sequence of actions could be described in more detail on a separate flowchart.

Manual Loop: Indicates a sequence of commands that will continue to repeat until stopped manually.

Loop Limit: Indicates the point at which a loop should stop.

Data storage: Indicates a step where data gets stored.

100

Contd.,

Database: Indicates a list of information with a standard structure that allows for searching and sorting.

Display: Indicates a step that displays information.

Off Page: Indicates that the flowchart is connected at a different page.

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