Computer studies analysis of questions and answers

Explain three functions of an information system in an organisation.

15/1/2021

Explain three functions of an information system in an organisation.

(b) Explain two benefits that a company would gain from using batch processing method for data processing

(c) (i) Convert the number 11101.1 1₂ to its decimal equivalent.
(ii) Perform the following binary operation 11011₂ + 101₂

RESPONSES

a) Functions of information system in an organization.

Process data in an organization according to the policies and objectives.
Decision making by providing information that helps with strategic planning within the organization.
Means of communication and flow of information to various sections of an organization / enable sharing of information.
Improving quality of production, through the use of feedback mechanisms for counter checking the production with expected results.

(b)Benefits of using batch processing.

Output is increased because the processor work is uninterrupted.
Low cost of operation since the tasks are processed as a group.
Requires little supervision since the processing runs automatically as long as the instructions is given.
Less labour required since the process is automatic.
Efficient use of computer resources due to no idle time.
Gives company opportunity to check any error before processing begins.

(c) (i) Convert the number 11101.1 12 to its decimal equivalent. (ii) Perform the following binary operation 110112 + 1012

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Describe three arithmetic errors that may occur during computerised data processing.

15/1/2021

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Describe three arithmetic errors that may occur during computerised data processing.

(b) Arnold a programmer intends to create a user input interface screen for a system. State three factors that he should consider.
(c)With the aid of an example in each case describe the following types of maintenance.
(i) adaptive;
(ii) perfective;
(iii) corrective.

RESPONSES

a) Arithmetic errors
Truncation error

Results due, to shortening or leaving out part of a number or a word.
Rounding off error
Arising by approximating a number by replacing it with a number that has fewer significant digits or one with zeros for its ending digits.

Overflow error

Occurs when the results of a computation is larger than the allocated memory space.

Underflow error

Type of error occurs when the output is low small to be represented in the chosen format.

b) User interface design considerations

Should be user friendly.
Colour, fonts and layout should be appealing to the user.
Consider a consistent layout in the entire system.
Should prompt user clearly.
Should capture the same number of items of date as indicated in the manual data capture form.

(c)Types of maintenance
(i) Adaptive

Type of maintenance that is done to make the system to adopt the changing technology e.g. changing the system because to new ois

(ii) Perfective

Type of maintenance done to make the system better in its operation e.g. adding a module in a system.

(iii) Corrective

Type of maintenance done to correct an error in the system e.g.wrong results during addition.

a) Arithmetic errors Truncation error Results due, to shortening or leaving out part of a number or a word. Rounding off error Arising by approximating a number by replacing it with a number that has fewer significant digits or one with zeros for its ending digits. Overflow error Occurs when the results of a computation is larger than the allocated memory space. Underflow error Type of error occurs when the output is low small to be represented in the chosen format. b) User interface design considerations Should be user friendly. Colour, fonts and layout should be appealing to the user. Consider a consistent layout in the entire system. Should prompt user clearly. Should capture the same number of items of date as indicated in the manual data capture form. (c)Types of maintenance (i) Adaptive Type of maintenance that is done to make the system to adopt the changing technology e.g. changing the system because to new ois (ii) Perfective Type of maintenance done to make the system better in its operation e.g. adding a module in a system. (iii) Corrective Type of maintenance done to correct an error in the system e.g.wrong results during addition.

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A water company sends out clerks to read meters. The data collected by the clerks is then fed into the computer and then all bills are printed at the same time.

13/1/2021

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A water company sends out clerks to read meters. The data collected by the clerks is then fed into the computer and then all bills are printed at the same time.

(a)State two advantages of this approach;

Shifts time of processing to when computers are less busy.
No user input required hence no idle computer time as it awaits input.
Input is done once (batch).
Can enable use of hired equipment hence cost effective.

(b) Name this type of data processing.

Batch processing.
Electronic

A water company sends out clerks to read meters. The data collected by the clerks is then fed into the computer and then all bills are printed at the same time.

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List two techniques of acquiring electronic images to be used in a desktop publishing program.

10/1/2021

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List two techniques of acquiring electronic images to be used in a desktop publishing program.

(ii) Describe two layout guides in a desktop publishing program (DTP) that assist a user to place an object in a preferred position.
(b) Explain three ways of ensuring that data submitted for processing is accurate.
(c)An engineering company requires a computer system to design roads and bridges.
Explain one suitable choice for:
(i) output device;
(ii) software.

RESPONSES

(a) (i) Ways of acquiring images in DTP:

Scanning;
Picture capture via camera;
downloading;
getting from secondary storage.

(ii) Layout guides

Ruler guides: a ruler on the edges of the page that guides a user to position objects and resize them;
Margin guides: used to define page margins so that the user will be prevented from placing objects in non-printable areas of the page;
Column guides: Vertical lines used to divide a page into two or more columns;
Row guides: Lines used to divide a publication page into two or more section to help structure the layout;
Snap points: Positions on the screen where the object is stuck on.

(b) Ways of ensuring accuracy of data during data processing

Data is stored in secondary storage in such a way that access to it is controlled.
Encrypting of data before it is transmitted to minimize chances of it being compromised during transmission.
Use of validation methods to ensure that data is correct at the point of input.
Use of direct data capture methods which eliminates human errors.
Use of verification methods.

(c) (i) Output device: A plotter because it prints large size drawings to high precision.
(ii) A CAD software because it facilitates in the design of engineering drawings.

(ii) Describe two layout guides in a desktop publishing program (DTP) that assist a user to place an object in a preferred position. (b) Explain three ways of ensuring that data submitted for processing is accurate. (c)An engineering company requires a computer system to design roads and bridges. Explain one suitable choice for: (i) output device; (ii) software.

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State three functions of networking operating systems other than providing network security.

10/1/2021

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State three functions of networking operating systems other than providing network security.

(b) Explain three ways in which an operating system provides data security in a computer system.
(c) Explain three circumstances under which observation method may be preferred during data collection.

(a) Functions of network operating systems

Provide access to network resources;
Supporting network services like protocols;
Support communication;
Respond to requests from applications;

(b) Ways in which an operating system provides data security

Access control: Deals with the problem of verifying /authenticating the identity of a user before permitting access to the request resource (e.g. use of passwords, user account);
Encryption - Transforming data into an unreadable format so that they are safely transmitted;
Firewalls - Filters out unwanted data and programs/criminals/hackers/malicious persons;
Log files - A means by which transactions in a computer system can be recorded thereby deterring potential infiltrators;
Alerts - Alerting a user when he/she is about to delete a file/folder.

(c)Preference of observation during data collection

When the subjects that are being observed need not be made aware of the fact;
When there is need to directly see what subjects do rather than rely on what they tell you;
When there is need to collect data without interfering with the working of the subjects;
When nature of data can only be collected via observation e.g. traffic flow;
When collecting data in situation that subjects may be unwilling to give information.

(b) Explain three ways in which an operating system provides data security in a computer system. (c) Explain three circumstances under which observation method may be preferred during data collection.

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With the aid of a diagram. describe time sharing mode as used in computer data processing.

7/1/2021

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With the aid of a diagram. describe time sharing mode as used in computer data processing.

(b) A company’s management has opted to use computers to process data. State four factors that the management needs to consider when selecting the company data processing mode.
(c) Explain the purpose of each of the following in system documentation:
(î) user manual;
(ii) sample data:
(iii) table descriptions.

RESPONSES

(a) Time-sharing mode
This is a processing mode in which a central processor serves two or more users with different requirements. The processor time is divided equally
among the tasks in the queue. A user whose task requirements are more than is apportioned is send back to the queue. For example, four jobs requiring times t1, t2, t3 and t4 to complete is apportioned equal time in each round until when they are done.

With the aid of a diagram. describe time sharing mode as used in computer data processing.

(b) Factors to consider when selecting data processing mode

The optimisation of processing time;
The time factor required for decision arising from the processed data;
The ease of development, use and maintenance;
The control over the resources e.g. files, I/O devices e.t.c;
The need for the shared resources among several users who may afford purchasing their own facilities as in time sharing configuration;
The volume of work involved;
The cost of acquiring the relevant hardware. software. media e .t .c and the cost of maintenance;
The nature of the task to be processed.

It is a documentation whose purpose is to help a user to use the system with little guidance.

(ii) Purpose of sample data

Before the system is implemented, it has to be confirmed that it is functional. Sample data is meant to be used to test whether the system is giving desired output.

(iii) Purpose of table descriptions

They are details of table structures that the system will require for the purpose of designing the actual tables.

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State the type of error that would occur in data processing for each of the following cases:

7/1/2021

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(a) Entering the number 315 instead of 351. (1 mark)

Transposition error

(b) Entering the text “Kwys” instead of “Keys”. (1 mark)

Transcription error

State the type of error that would occur in data processing for each of the following cases:

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Describe three types of validation checks as used in data processing.

6/1/2021

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Describe three types of validation checks as used in data processing.

(b) A company has opted to store its employees’ personal details in a computer system.
Describe two software methods that may be used to prevent unauthorized access to these details.
(c) (i) Describe each of the following data processing modes:
I. real-time;
II. interactive.
(ii) State an application area where real-time data processing mode is applied.

RESPONSES

(a) Validation checks

Range checks: checks that data lies within a range of values.
Presence checks: checks that data is there and has not been missed out.
Length checks: checks that fields are of the right number of characters.
Type checks: checks that the data is of the right type.
Format checks: checks whether data is in the correct format.

(b) Methods to prevent un authorised access:

Password: A secret word; a string of characters known only to a restricted group for authentication.
User Access levels: A case where each group is granted different levels of access
User Access rights: An individual is granted access or denied access to resources.

(c) (i) (I) Real-time

In a real-time processing. there is a continual input, process and output of data instantaneously upon receipt of command.

(II) Interactive processing

A computer processing in which the user can modify the operation appropriately while observing results at critical steps.
(ii) Application area for real-time mode
Airline booking, medical system. car tracking system, hotel booking system, banking system.

(b) A company has opted to store its employees’ personal details in a computer system. Describe two software methods that may be used to prevent unauthorized access to these details. (c) (i) Describe each of the following data processing modes: I. real-time; II. interactive. (ii) State an application area where real-time data processing mode is applied.

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What is an information system?

5/1/2021

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What is an information system?

(a) (i) What is an information system?
(ii) State two roles of an information system.
(b) Describe the following file organisation methods:
(i) random file organisation;
(ii) sequential file organisation.
(c)The following records were extracted from two files that contained student data.

(i) Which of the two files above represents a Transaction file?
(ii) Give a reason for your answer in c(i) above.
(iii) Name the other type of file represented above.
(d)An airline uses an information system whereby if a passenger at station A books a plane seat,this transaction is immediately shown at stations A and B such that no other passenger can book the same seat.
(i) Identify this data processing mode.
(ii) State two advantages and two disadvantages of this data processing mode.

RESPONSES

(a)(i) Information system is an arrangement of people, data, processes, communication and IT that interact to support problem solving.
(ii) Improve day-to-day operation

Support problem solving
Support decision making needs for management
Data capture
Processing data into information
Data security
Storing of data/information

(b) (i) Stored and retrieved according to their disk address which is generated by use of an algorithm or formula i.e. stored randomly, accessed randomly.
(ii) Method of storing or retrieving information that requires the program to start reading at the beginning and continue until it finds the desired data.
(c) (i) File B.
(ii) Transaction file: It contains data which is regularly added.
Has data/fee payment .
(iii) Master File: It contains records that do not change regularly like in file A.

(d) (i) Real time processing.
(ii) Advantages

Information is readily available for instant, decision making.
Updating is done instantly when transaction occurs.
Auditing is easier.
It is accurate
Prevent double booking

Disadvantages

Complex - difficult to configure/set up.
Expensive to acquire and maintain.
Errors that occur are difficult to correct

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Describe each of the following validation checks as used in data processing

4/1/2021

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(a) Describe each of the following validation checks as used in data processing:

(i) Preserve check

It is a measure placed used to ensure that data item is in its original status.

(ii) Data type check

It is a measure that ensures that correct data type is entered for each field.

(iii) Check digit

This is a number calculated by the computer to make sure that the other numbers in a sequence have been entered properly.

Describe each of the following validation checks as used in data processing:

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State four computer based careers introduced as a result of computerized data process method at the airport.

4/1/2021

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State four computer based careers introduced as a result of computerized data process method at the airport. (2 marks)

Computer based careers created by introducing computerized data processing.

System analysts
Hardware technicians
Data entry clerks
Programmers
Networks technicians
Database administrators
Web designers
Network administrator

State four computer based careers introduced as a result of computerized data process method at the airport

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Distinguish between real-time operating system and distributed operating system.

4/1/2021

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Distinguish between real-time operating system and distributed operating system. (3 marks)

Distinction between real-time and distributed OS.
Real-time OS reads information from input devices and must respond within a short duration of time to ensure correct performance.
Distributed OS distributes computation among several physical processors which do not share memory or clock.

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Explain three reasons why an organization may need to change to a new computerised system.

4/1/2021

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Explain three reasons why an organization may need to change to a new computerised system.

(b) State why each of the following is important in system documentation.

(i) sample data;
(ii) output reports.

(i) manual:
(ii) electronic.

(d)A teacher manages students’ records by storing daily attendance information in a tile called register and students’ personal records such as year of birth and home address in a file called students.
(i) Identify the types of computer files named above.
(ii) Give a characteristic of data held in each file.
(iii) Name the field that should be used to link the two files.

(a) Current system may be experiencing problems thereby being unable to meet organisation requirements.
New directives may be received from authorities and the organisation must comply.
Changes in the operating environment forces the organisation to change in order to fit and continue in business. e.g. competition.
Changes in technology requiring the upgrading or total change in the existing system.
Peer pressure need to remain fashion
(b) (i) Sample data should be provided so that all modules can be tested.
(ii) Output reports show that the system actually works/testing process/expected output..
(c) (i) Manual: Manual files stored in cabinets/books/paper/in-tray/out-tray.
(ii) Electronic: Secondary storage devices/individual storage devices e.g. Flash.
(d) (i) Student: Master file/Parent/Reference File/Primary.
Register: Transaction file/Child table/Secondary.
(ii) Master file: Data is static/Permanent/Semi-permanent.
Transaction file: Data is dynamic/Temporary/Changes frequently
(iii) Key field: Student number/Admission No/Reg. No/File No.

Explain three reasons why an organization may need to change to a new computerised system.

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State two application areas of real time systems.

4/1/2021

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State two application areas of real time systems.

Booking and reservations. eg. hotel, car, bus, air ticket.
Space explorations.
Intensive care units (hospital). (ICU)
Chemical plants/nuclear
Military security
Banking eg. ATM.

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A water company sends out clerks to read water meters. The data collected by the clerks is then fed into the computer and then all the bills are printed at the same time.

4/1/2021

0 Comments

A water company sends out clerks to read water meters. The data collected by the clerks is then fed into the computer and then all the bills are printed at the same time.

(a) State two advantages of this approach.

Advantages:

Shifts time of processing to when computers are less busy.
No user input required hence no idle computer time as it awaits input.
Input is done once (batch).
Can enable use of hired equipment hence cost effective.

(b) Name this type of data processing.

Batch processing.
Electronic.

A water company sends out clerks to read water meters. The data collected by the clerks is then fed into the computer and then all the bills are printed at the same time.

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ANALYSIS OF KCSE COMPUTER STUDIES TOPICAL QUESTIONS & REVISION KITS

Explain three functions of an information system in an organisation.

Describe three arithmetic errors that may occur during computerised data processing.

A water company sends out clerks to read meters. The data collected by the clerks is then fed into the computer and then all bills are printed at the same time.

List two techniques of acquiring electronic images to be used in a desktop publishing program.

State three functions of networking operating systems other than providing network security.

With the aid of a diagram. describe time sharing mode as used in computer data processing.

​(a) Entering the number 315 instead of 351. (1 mark)

​(b) Entering the text “Kwys” instead of “Keys”. (1 mark)

Describe three types of validation checks as used in data processing.

What is an information system?

RESPONSES

​(a) Describe each of the following validation checks as used in data processing:

(i) Preserve check

(ii) Data type check

(iii) Check digit

​State four computer based careers introduced as a result of computerized data process method at the airport. (2 marks)

Distinguish between real-time operating system and distributed operating system. (3 marks)

Explain three reasons why an organization may need to change to a new computerised system.

State two application areas of real time systems.

A water company sends out clerks to read water meters. The data collected by the clerks is then fed into the computer and then all the bills are printed at the same time.

​(a) State two advantages of this approach.

(b) Name this type of data processing.

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(a) Entering the number 315 instead of 351. (1 mark)

(b) Entering the text “Kwys” instead of “Keys”. (1 mark)

(a) Describe each of the following validation checks as used in data processing:

State four computer based careers introduced as a result of computerized data process method at the airport. (2 marks)

(a) State two advantages of this approach.