SYSTEM AND DESIGN 1

System Analysis and Design Unit 9

Sikkim Manipal University Page No. 198

Unit 9 System Analysis – II

Structure: 9.1 Introduction

9.2 File Organisation

Serial organisation

Sequential organisation

Indexed sequential organisation

Inverted list organisation

Random file organisation

9.3 System Testing

9.4 Test Plan and Test Data

Test plan

Test data

9.5 Types of System Test

Unit testing

Integration testing

System testing

9.6 Summary

9.7 Glossary

9.8 Terminal Questions

9.9 Answers

9.10 References

9.1 Introduction

In the previous unit, you studied information gathering tools like interviews,

questionnaire, etc. Also you came to know about different tools of structured

analysis like data flow diagram (DFD), data dictionary, etc.

In this unit, we will study the concept of file organisation and system testing.

You will study various methods of organising files like sequential, indexed

sequential, etc. Also, you will understand the concept of test plan and test

data. You will study various types of system test which include unit testing,

integration testing, etc.

You can define file organisation as a process of accumulating data in a file.

There are a various methods of organising files which are discussed in this

unit. System testing is defined as a process of carrying out various tests on

http://www.businessdictionary.com/definition/process.html

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a system to discover functionality or to recognise the problems occurring in

the system.

Objectives:

After studying this unit, you should be able to:

describe various methods used for organising files like sequential,

indexed sequential, etc.

explain the concept of system testing

describe test plan and test data

discuss the various types of system test used for testing.

9.2 File Organisation

A file can be defined as a collection of associated records collected at a

common place making the data easy to retrieve and store with day-to-day

basis. You can limit the size of a file by the size of memory or the storage

medium. Activity and volatility are the two characteristics that determine how

files are organised.

File activity is used to identify the actual records percentage processed in a

single run. At any specified time, if less proportion of records is accessed,

then the file organisation takes place on disk for direct access. On the

contrary, if a large percentage of records are affected on a regular basis,

then organising the file on tape would be more efficient and less expensive.

File volatility is used to address the properties of record changes. File

volatility is a measure of the number of records added or deleted as

compared to the original number of records. File records with considerable

changes are extremely volatile. This signifies that the disk design would be

more efficient than tape.

For example, consider airline reservation system and the high volatility in

the course of cancellations, additions, and other transactions, in comparison

to traditional payroll which is comparatively inactive. Disk design will be

more striking if the volatility is higher.

File organisation is performed to make sure that records are obtainable for

processing. It should be designed in order with the activity and volatility of

the information and the nature of the storage media.

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Other considerations are:

Cost of file media

Requirements for enquiry

File confidentiality, integrity, safety and privacy.

There are various methods of organising files (See figure 9.1)

Figure 9.1: Types of File Organisation

Now, let us discuss these methods in detail.

9.2.1 Serial organisation

Serial organisation is defined as the process of storing records serially

without any logical order i.e., as and when a record is received, it is stored in

the next available position.

In table 9.1, we have demonstrated an example of file in serial organisation

where the order no. 0755 can be accommodated after order no. 8302. Thus,

the records are not required to be stored in ascending or descending order

of any field. You can add the record only at the end of a file. You can

retrieve a particular record only by reading its previous records from the

beginning of file as shown in figure 9.2.

Table 9.1: An Example of File with Serial Organisation

Order No. Sup. No. Supplier Name

1149 S01 Calder, James

8302 S04 Brand, Matt

0755 S02 Teff, Sam



Figure 9.2: A Serial File

Advantages of serial organisation: The simplest method of file

organisation is the Serial Organisation. We generally use serial organisation

method for accumulating the transaction data of those applications where

records are accessed in their storage order.

Disadvantages of serial organisation: The disadvantages of files that are

organised in a serial manner are:

In serially organised files, the process of records retrieval is very slow.

It is difficult and time consuming to delete and modify a particular record.

9.2.2 Sequential organisation

Sequential file organisation is defined as the process of arranging the

records sequentially in a predetermined order. In table 9.2, we have shown

an example of file with sequential organisation where the record with Order

No. 8302 will appear after the record with Order No. 0755.

In Sequential file organisation, you can store and arrange the records in

continuous blocks on tape or disk. The records are arranged in ascending or

descending manner in each block. This is done to make the logic simpler for

accessing the data. Sequential organisation is shown in figure 9.3.

Table 9.2: An Example of File with Sequential Organisation

Order No. Sup. No. Title of Book

0755 S02 Teff, Sam

1149 S01 Calder James

8302 S04 Brand, Mat



Figure 9.3: A Sequential File

Advantages of sequential organisation: The sequential file organisation

is a traditional and very commonly used method of data storage because of

following reasons:

Sequential file organisation method is appropriate for applications that

use batch processing.

You can store the sequential files on magnetic tapes which are the least

costly storage devices.

Disadvantages of sequential organisation: The disadvantages of

sequential files are as follows:

When the number of records is high, the sequential files are not efficient.

This is because, on an average, one-half of the records have to be

processed when looking for a particular record.

The processing turns out to be time-consuming when there is a need to

modify or delete a less number of records. This is because the magnetic

tapes do not allow a record to be updated at similar location. You should

read the whole file first and then rewrite it on another tape.

9.2.3 Indexed sequential organisation

As the name suggests, Indexed sequential files are based on the concept of

an index of the contents. For example, a book contains different topics

which are organised in some sequence and it also includes an index at the



end. You can search the page number of any topic by just going through this

index. Likewise, in Indexed Sequential Organisation, the records are

accumulated in sequence on a data file. However, a second file (known as

Index File) also appears which allows accessing any record directly.

Thus, you can access the records of indexed sequential files sequentially as

well as directly. Direct Access Storage Device (DASD) is used to store the

files for indexed sequential organisation. The floppy and hard disks are

generally considered as direct access storage devices.

Let us first discuss the different areas of disk storage to recognise the

indexed sequential organisation. The three areas of storage where data is

stored are:

Prime Area: When an indexed sequential file is formed initially, the

records are written on an area, known as prime area. This area includes

the records accumulated in logical sequence of key field. The prime area

and sequential file are considered to be similar.

Overflow Area: Overflow area includes those records which can be

added afterwards and cannot be accumulated in prime area.

Index Area: The values of key fields of records and their storage

locations on the disk are included in an index area.

Let us see an example to understand the indexed sequential organisation.

Suppose a database file contains the fields—Employee No. and Name. In

table 9.3, we have shown that the records of this file are accumulated in

different area of storage.

In case of prime area, block 1 contains the employee no. 01, 04 and 10 and

block 2 contains employee no. 11, 15 and 20. Every record points to the

address of main location and the address of overflow location. The address

of main location and the address of overflow location are known as record

pointer and overflow pointer, respectively. The employee number (key field)

and the address of its main location for every record are contained in an

index area. The overflow area includes employee number, employee name

and its overflow address for every record which is incorporated afterwards.

You can see that employee no. 01 points to record pointer 1002 and

overflow pointer 2000 in prime area. In case of index area, employee no. 01

is indicated by index value 1002. Thus, this record can be read from prime



area by looking for its index value. The new record with employee no. 02,

when incorporated afterwards, is accumulated in overflow area and its

overflow pointer value will be 2000. So, this new record is stored logically in

ascending sequence of Employee no. but physically accumulated on

another storage area.

Advantages of indexed sequential files: The advantages of indexed


The indexed sequential files offer a very powerful tool to the user. Apart

from processing the files sequentially, they can also be processed

randomly.

In these files, the searching is very quick since the file management

system processes the data records in line with its index value. This

method is known as the Indexed Sequential Access Method (ISAM).

You can also call these files as ISAM files.

Unlike sequential files, when records are updated or inserted, rewriting

the entire file is not required.

Table 9.3: An Example of Indexed Sequential File displaying

Areas of Storage Prime Area

Employee No. Employee Name Record Pointer Overflow Pointer

01 PreetiArora 1002 2000

04 Dr.Suchitra 1006 2010

10 Gaurav 1010 2020

11 Dr.Surendra Kumar 1202 3000

15 Sweety 1206 3090

20 Dr.SudhirKhetrapal 1210 3020

Index Area

Employee No. Record Pointer

202 S01

199 S02

198 S04

200 S03

201 S02



Overflow Area

Employee No. Employee Name Overflow Pointer

02 Mrs.Lajwanti 2000

12 BaldevArora 3000

05 Anita Arora 2010

Disadvantages of index sequential files: The disadvantages of indexed


These files must be accumulated on a direct access storage device like

floppy disk, hard disk, etc. and cannot be accumulated on magnetic

tapes.

These files need regular preservation or else the records added in end

overflow area are not included into the main file.

9.2.4 Inverted list organisation

The inverted list organisation is used to maintain an index similar to the

indexed sequential method. The two methods vary, however, in the index

level and record storage. A single index is contained in the inverted list

method for each key type whereas the indexed sequential method includes

a multiple index for a specified key. In an inverted list, it is not necessary to

accumulate the records in a particular sequence. The records are located in

the data storage area. However, you can update the indexes for the record

keys and location.

Example: let us take an example of airline Air India. The flight number, flight

departure time and flight description are all defined as keys, and an

independent index is kept for each. Now let us assume that a passenger

asks information about the Kolkata flight. The agent asks for the record with

the flight description “Kolkata flight." The DBMS then interprets the single-

level index sequentially till it discovers the key value for the Kolkata flight.

This value has two records linked with it: A2 and A8. The DBMS basically

tells the agent that flight No.1070 is starting at 10:10 A.M. (A2) and flight

No.1269 is departing at 8:15 A.M.

Now, let us look at inverted-list organisation in a different manner, let us

assume the passenger requests information for a Kolkata flight that leaves

at 8:15. The DBMS in the beginning looks for the flight description index for

the value of the “Kolkata flight. It finds A2 and A8. After that, it looks for the

flight departure index for these values. It. finds that the A2 value leaves at



10:10, but the A8 value leaves at 8:15. The record at position A8 in the data

location area is exhibited for follow up.

Advantages of inverted list organisation: The Inverted List Organisation

includes the following advantages:

The inverted lists are best suitable for applications that demand

particular data on numerous keys.

They are perfect for static files as additions and deletions leads to costly

pointer updating.

9.2.5 Random file organisation

The file organisation where records are organised at random and are not

required to be in sequence is called Random or Direct File Organisation.

In direct access or random file organisation, records or files are positioned

at random. There is no need for records to be in sequence since you can

update the records directly and rewrite them back in the similar location.

Based on software commands, new records are added at the end of the file

or inserted in desired locations.

Records are obtained by addresses that state their disk locations. You need

an address for locating a record, for connecting records or for setting up

relationships.

There are two types of addresses, that is, absolute or relative. An absolute

address signifies the physical location of the record. It is generally specified

in the format of sector/track/record number. For example, 4/13/5 signifies,

go to sector 4, track 13 of that sector and the fifth record of the track.

One difficulty that occurs with absolute address is that they turn out to be

invalid when the file including the records is repositioned on the disk. One

approach to avoid this is to use pointers for the updated record.

A relative address offers a record location in relation to the starting of the

file. Fixed length records must be there for reference. A record can also be

located by the number of bytes it is from the starting of the file. Dissimilar to

absolute addressing, if the file is moved, pointers are not required to be

updated. This is because the relative location of the record is the same as

before.



The address of a record can be determined by transforming the record key

value into an arithmetic formula. This is known as hashing technique. Under

this process, each record is stored at a location whose Storage Record

Address (SRA) is computed as some mathematical function called hash

function.

Advantages of random file organisation: The advantages of random file

organisation are as follows:

In Random File Organisation, the records are provided with the fastest

direct access.

Random File Organisation is appropriate for applications that need

online enquiry and updating like air Ticket Bookings and Bank Account

Statements Program.

Disadvantages of random file organisation: Even though, random file

organisation is appropriate for online application, it also includes some

limitations. The main difficulty with hashing technique in random file

organisation is the occurrence of synonymous SRA. Hashing can generate

the same storage location (SRAs) for two dissimilar records. These record

keys are known as synonyms.

Self Assessment Questions

1. File organisation depends on two characteristics, that is, activity and

____________________.

2. Serial Organisation method is used to store the records serially without

any logical order. (True/False)

3. Organising the records sequentially in a predetermined order is known

as ___________________ file organisation.

4. Direct Access Storage Device (DASD) is used to store the files for

sequential organisation. (True/False)

5. ________________ File Organisation includes organising the records

randomly and there is no need for the records to be in sequence.



Activity 1

Visit a nearby organisation and find out the method of file organisation

used and the reason for the use of that particular method. Also, find out

the activity and volatility of their files. Is the method used, efficient for the

kind of business or trade the organisation deals in?

9.3 System Testing

Testing is considered as the most time-consuming, but an important phase

of a system project. Testing is essentialfor the achievement of an effective

system.

However, in development phase, programmers also perform testing of their

programs, but they usually do not perform testing in a methodical manner.

They mainly focus on eliminating syntax and some logical errors of

programs.

Figure 9.4: System Testing

After coding, each program unit must be tested to ensure that it works in a

correct manner. Afterwards, programs are tested in groups, and lastly the

entire system is tested by the development team. The first step is to compile

the program. This is done by means of a CASE tool or a language compiler.

This procedure identifies syntax errors, which are known as language

grammar errors. The errors are corrected by the programmer until the

execution of a program correctly.



Then, the program is checked by the programmer desk. Desk checking is

the procedure of analysing the program code to detect logic errors, which

generate erroneous outcomes. This procedure can be carried out by the

person who wrote the program or by other programmers. A process where

desk checking is performed more formally is known as a structured

walkthrough, or code review. This process is needed by various

organisations.

Besides examining or analysing logic and program code, the project team

also carries out a meeting with users known as a design walkthrough. This

is done to review the system and have a discussion with people who will

work with the new system and make sure that all essential features have

been incorporated. This is a continuance of the modelling and prototyping

attempt that started early in the systems development process.

In integration testing, individual software modules are combined and tested

as a group after the unit testing is completed as opposed to system testing

where complete system is configured in a controlled environment and

tested. Integration testing takes as its input modules that have been unit

tested, groups them in larger aggregates, applies tests defined in an

integration test plan to those aggregates, and delivers as its output the

integrated system ready for system testing. System testing, integration

testing and unit testing are explained in detail later in the chapter. The

applications of system testing can be understood better with the following

figure 9.5.

Figure 9.5: Application of System Testing



Now let us understand the concept of test plan and test data which plays an

important role in testing. These are discussed in the following section.


6. _______________ of a program is done by means of a CASE tool or a

language compiler.

7. When the project team holds a meeting with users, this process is

known as a structured walkthrough. (True/False)

9.4 Test Plan and Test Data

Now let us study in detail about test plan and test data.

9.4.1 Test plan

A Test Plan is considered as a document that demonstrates the systematic

approach for system testing. It illustrates the scope, strategy, resources and

schedule of projected test activities. It recognises test items; the features

that are to be tested; the tasks relating to testing; who will perform each

task; and any risks that require emergency planning.

Purpose of preparing a test plan: The major reason of a Test Plan

preparation is that everyone related with the project are aware of the scope,

responsibilities, targets and deliverables for the project. This shows that

reviews are very significant as it implies that everyone knows about the

contents of the test plan. It also assists in case of any argument in the

course of the project (particularly among the developers and the testers).

9.4.2 Test data

A System is programmed with the help of its data. If data is poor, functional

testing can suffer, and if data is good, it can enhance functional testing.

Structuring good test data can boost understanding and testability. Its

contents, rightly picked, can decrease maintenance efforts and permit

flexibility.

Test data should however, be prepared which represents usual transactions

of business. Real user names or contact details should not be utilised for

such tests. An exclusive reference number is provided to each separate test

toidentify the Business Process being recorded, the persons concerned with

the testing process and the date the test was performed. Thus, the



monitoring and testing reports will be developed with the help of the reviews

received.

You should be clear regarding the methodology used for the test. You can

design better test cases by making the plan more formal. You must

recognise the limits inbuilt in the tests themselves. You must have a steady

schedule for testing. Performing a particular set of tests at suitable points in

the process is more significant than running the tests at a particular time.

Roles of data in functional testing: A large amount of data is consumed

and produced by testing. Data is influenced, extrapolated, summed up and

referenced by the functionality under test, which lastly sends out more data

to be checked against expectations.

Data is an essential part of most functional testing. Testing can be improved

by a cautious selection of input data. The various factors are described

below.

1. A system is programmed by its data: Many current systems permit

incredible flexibility in the manner their fundamental functionality can be

used. Configuration data can state control flow, data handling,

presentation and user interface. A system can be configured to fit

numerous business models, work (almost) flawlessly with various

cooperative systems and offer modified experiences to a host of

dissimilar users.

2. Functional testing suffers if data is poor: Tests having poor data may

not illustrate the business model efficiently. They may be tough to

preserve, or need lengthy and complicated setup. They may obscure

difficulties or avoid them on the whole. Poor data is likely to effect in

poor tests that take much time to perform.

3. Good data is vital to reliable test results:The main objective of

functional testing is to permit the test to be repeated with the similar

result, and varied to permit analysis. Without this, it is hard to converse

problems to programmers, and it can turn out to be complicated to have

assurance in the QA(Quality Assurance) team's outcomes, whether they

are good or bad. Good data permits analysis, effective reporting, and

permits tests to be repeated with assurance.



4. Good data can help testing stay on schedule: A simply logical and

well-understood dataset is a tool used to assist communication. Good

data can to a great extent help in quick analysis and quick re-testing.

Regression testing (Regression testing is type oftesting that seeks to

uncover new software bugs, or regressions, in existing functional and

non-functional areas of a system after changes have been made to

them) and computerised test maintenance can be made faster and

simpler by means of good data, while an elegantly selected dataset can

frequently permit new tests without the overhead of new data. A

document that offers and keeps a record of significant information

regarding a test project is considered as a formal test plan.


8. A Test Plan is a helpful method to plan through the attempts required to

____________________ the acceptability of a system product.

9. Tests having poor data can describe the business model efficiently.

(True/False)

9.5 Types of System Test

The major types of system tests used to perform testing include unit testing,

integration testing, and system testing. These are shown in figure 9.6 as

below.



Figure 9.6: Types of System Tests

The first step in testing is unit testing, followed by integration testing, and

then system testing. Now, let us discuss these different types of system

tests.

9.5.1 Unit testing

Unit testing is defined as the testing of an individual program or module. The

purpose is to recognise and remove execution errors that could make the

program to terminate unusually, and logic errors that could have been

overlooked throughout desk checking.

Test data should enclose both accurate data and erroneous data and should

test all probable situations that could take place. For example, for a field that

permits a range of numeric values, the test data should enclose minimum

values, maximum values, values outside the suitable range, and

alphanumeric characters. Throughout testing, programmers can make use



of software tools to find out the location and possible causes of program

errors.

In unit testing, programmers test theprograms that interrelate with other

programs and files independently, before they are incorporated into the

system. This needs a technique known as stub testing.

In stub testing, the programmer simulates each program conclusion or

result and exhibits a message to specify whether or not the program is

executed in a successful manner. Each stub displays an entry or exit point

that will be linked afterwards to another program or data file.

9.5.2 Integration testing

Integration testing is defined as a testing of two or more programs that rely

on each other. It is also known as link testing. For example, consider a

system with a program that verifies and confirms client credit status, and a

different program that updates data in the client master file. The output from

the validation program turns out to be input to the master file update

program. Testing the programs separately does not assure that the data

passed among them is accurate.

Only by carrying out integration testing for this pair of programs can you

confirm that the programs work jointly in a proper manner. Figure 9.6 display

integration testing for numerous groups of programs. Remember, that a

program can contain membership in two or more groups.

Systems analysts typically produce the data that they utilise in integration

testing. Similar to the case with all types of testing, integration test data

takes into account both usual and unusual circumstances. For example,

integration testing might comprise passing typical records among two

programs, followed by blank records, to simulate an abnormal event or an

operational problem.

You should make use of test data that simulates real conditions since you

are testing the interface that connects the programs. A testing series should

not progress towards the integration test phase unless it has been carried

out properly in all unit tests.



9.5.3 System testing

After the completion of integration testing, you must carry out system

testing, which includes the whole information system, as displayed in figure

9.6. A system test involves all usual processing situations and is projected

to guarantee users, developers, and managers that the program fulfils all

specifications and that all essential features have been incorporated.

Throughout a system test, users enter data, as well as samples of actual, or

live data, execute queries, and generate reports to reproduce actual

operating conditions. Users and the IT project development team confirm all

processing choices and outputs to make sure that the system functions

accurately.

Commercial systems must experience system testing similar to that of in-

house developed systems, even though unit and integration testing typically

are not performed. Irrespective of the way the system was generated,

system testing includes the following main objectives:

Execute a final test of all programs.

Verify that the system will manage all input data correctly, both valid and

invalid.

Make sure that the IT staffs have the documentation and instructions

required to operate the system in a proper manner and that backup and

restart competencies of the system are sufficient.

Show that users can interrelate with the system productively.

Verify that all system components are incorporated properly and that

real processing situations will be managed correctly.

Confirm that the information system can manage expected volumes of

data in a timely and competent manner.

Successful achievement of system testing is the key to user and

organisation’s permission, which is why system tests at times are known as

acceptance tests.

Final acceptance tests, though, are carried out throughout systems

installation and evaluation.

How much testing is required? The answer relies on the condition and

needs good decision and input from other IT employees, users, and

management.



Unfortunately, IT project managers frequently are forced to complete testing

quickly and hand over the system to users.

Common reasons for untimely or quick testing are demands from users,

tight systems development budgets, and demands from top organisation to

complete projects before time. Those pressures delay the testing process

and frequently have harmful effects on the finalproduct.

You should consider detailed testing as a cost-effective means of offering a

quality product. Every error trapped throughout testing removes potential

expenses and operational difficulties. No system, however, is 100% error-

free. Frequently, errors go unnoticed until the system turns out to be

operational. Errors that affect the reliability or correctness of data must be

corrected instantly. Small errors, like typographical errors in screen titles,

can be corrected afterward.

Some users prefer a system that is a totally finished product, whereas

others realise that small changes can be considered as maintenance items

after the system is prepared.

In the final analysis, you must make a decision whether or not to delay

system installation if problems are exposed. If contradictory views occur,

management will make a decision whether or not to install the system after

a complete discussion of the choices.


10. In _________________ testing, the programmer simulates each

program result and displays a message to specify whether the program

is executed successfully or not.

11. Testing of two or more programs depending on each other is known as

link testing. (True/ False)

12. Throughout systems installation and evaluation, final ______________

tests are carried out.

Activity 2

Visit an organisation and talk to the programmer team. Analyse the steps

taken to test a system and list the errors observed. Also, conduct a stub-

testing for any of their programs and make a report.



9.6 Summary

Let us recapitulate the important concepts discussed in this unit:

File organisation depends on two characteristics, that is, activity and

volatility.

Serial Organisation is defined as the process of storing records serially

without any logical order.

Sequential file organisation is defined as the process of arranging the

records sequentially in a predetermined order.

In Indexed Sequential Organisation, the records are accumulated

sequentially on a data file where a second file (known as Index File) also

appears which allows accessing any record directly.

The inverted list organisation is used to maintain an index similar to the

indexed sequential method.

In direct access or random file organisation, records are positioned at

random all through the file.

System testing performs different types of tests in a system and

identifies the errors occurring in the system.

A Test Plan is considered as a document that illustrates the scope,

strategy, resources and schedule of projected test activities.

The purpose of unit testing is to recognise and remove execution errors

that could make the program to terminate unusually, and logic errors

that could have been overlooked throughout desk checking.

Integration testing is defined as a testing of two or more programs that

rely on each other.

During a system test, users enter data, as well as samples of actual, or

live, data, execute queries, and generate reports to reproduce actual

operating conditions.

9.7 Glossary

Indexed sequential organisation: Indexed sequential files are based

on the concept of an index.

Integration testing: It is defined as a testing of two or more programs

that rely on each other.

Inverted list organisation: It is used to maintain an index similar to the

indexed sequential method.



Random file organisation: It is a file organisation where records are

positioned at random all through the file.

Sequential file organisation: It is a file organisation where the records

are arranged sequentially in a predetermined order.

Serial organisation: It is a file organisation where the records are

stored one after another without any logical order.

System testing: It performs different types of tests in a system and

identifies the errors occurring in the system.

Test plan: A Test Plan is considered as a document that illustrates the

scope, strategy, resources and schedule of projected test activities.

Unit testing: Unit testing is defined as the testing of an individual

program or module.

9.8 Terminal Questions

1. What is file organisation? List out different methods used for organising

files.

2. Explain the organisation of a sequential file with a suitable example.

Also describe the advantages and disadvantages of a sequential file

organisation.

3. Explain the concept of indexed sequential file organisation with example.

Describe its advantages and disadvantages.

4. Explain the concept of test plan and test data used in testing.

5. What is system testing? Make distinction between unit testing and

integration testing.

9.9 Answers


1. Volatility

2. True

3. Sequential

4. False

5. Random or Direct

6. Compilation

7. False



8. Authenticate

9. False

10. Stub

11. True

12. Acceptance

Terminal Questions

1. File organisation is performed to make sure that records are obtainable

for processing. Various methods of organising files are:

Serial Organisation

Sequential Organisation

Indexed Sequential Organisation

Inverted List Organisation

Random File Organisation

Refer section 9.2.

2. Sequential file organisation is defined as the process of arranging the

records sequentially in a predetermined order. One of the advantages of

sequential file organisation is that you can store the sequential files on

magnetic tapes which are the least costly storage devices. One of the

disadvantages of sequential file organisation is that the processing turns

out to be time-consuming when there is a need to modify or delete a

less number of records. Refer section 9.2.

3. Indexed sequential files are based on the concept of an index. In

Indexed Sequential Organisation, the records are accumulated in

sequence on a data file. A second file (known as Index File) also

appears which allows accessing any record directly. One of the

advantages of indexed sequential file organisation is that the searching

is very quick since the file management system processes the data

records in line with its index value. One of the disadvantages of indexed

sequential file organisation is that these files need regular preservation

or else the records added in end overflow area are not included into the

main file. Refer section 9.2.

4. A Test Plan is considered as a document that illustrates the scope,

strategy, resources and schedule of projected test activities. The major

reason of a Test Plan preparation is that everybody related with the



project are aware of the scope, responsibilities, targets and deliverables

for the project. A System is programmed by means of its data. If data is

poor, functional testing can suffer, and if a data is good, it can assist in

enhancing functional testing. Refer section 9.4.

5. System testing is a process that performs different types of tests in a

system and identifies the errors occurring in the system. Unit testing is

defined as the testing of an individual program or module. On the other

hand, Integration testing is defined as a testing of two or more programs

that rely on each other. It is also known as link testing. Refer section

9.3and 9.5.

9.10 References

Dorothy, J. Tudor; Ian J. Tudor., System Analysis and Design: A

Comparison of Structured Methods, 1995, NCC Blackwell

Leonard, Fertuck., System Analysis and Design, 1994, McGraw-Hill

Higher Education

John, W. Satzinger, Jackson, Burd., System Analysis & Design, 2006,

Thomson Learning

E-references:

http://instructional1.calstatela.edu/dgadish/CIS%20520/CIS520_CH10.

pdf, 21-03-12

http://www.exforsys.com/tutorials/testing/system-testing-

whywhathow.html, 21-03-12

http://www.pearsonschoolsandfecolleges.co.uk

http://www.pearsonschoolsandfecolleges.co.uk

http://www.kabinfo.net/kabinfol_SystemTesting.asp

http://books.google.co.in/books?id=xZVJKFtYrlsC&printsec=frontcover#

v=onepage&q=chapter11&f=false

http://www.pearsonschoolsandfecolleges.co.uk/

http://www.pearsonschoolsandfecolleges.co.uk/

http://www.kabinfo.net/kabinfol_SystemTesting.asp

Documents

SYSTEM AND DESIGN 1