KCSE Revision Resources

What is a source code as used in computer programming?

It is a program written in a high level langauage

State the name of the storage space used by the operating system when there is insufficient RAM

virtual memory

State two advantages of electronic databases over a flat file

Data Integrity: they provide ways or mechanisms for enforcing data integrity constraints, such as referential integrity. If a record in the parent table is deleted, related records in the child table also get deleted. This ensures accurthe acy and consistency of data stored in the database
Data Security
Concurrency control
Reduces data redundancy
Data retrieval and querying
Data indexing
Data consistency and acid transaction
Data backup and recovery
Data sharing and collaboration
Convenient data maintenance

Website data is broken down into packets to be transmitted to a user. Describe the structure of a data packet.

It has a header

that contains the destination address
that contains the packet number
that contains the originator’s address

It has a payload

It has a trailer.

Explain the Fetch – Execute cycle and provide an example of a Central Processing Unit (CPU) component for each stage of the cycle

The Fetch – Execute cycle is a sequence of actions, performed by the processor as it fetches
a program instruction from its memory, determines what the instruction wants to do and
carries out those actions. The stages of the cycle are provided below.

Fetch the instruction – the processor fetches the instruction from a memory address stored in a program counter and transfers the instruction, via a data bus, to an instruction register. At the end of the fetch operation, the counter points to the next instruction that will be read in the next cycle.
Decode the instruction – the processor decodes the instruction stored in the instruction register, including getting any operands required to complete the instruction.
Execute the instruction – the decoded instruction is executed.
Store the result – the result generated by the execute phase is stored in the main memory, and/or sent to an output device. The program counter is updated with feedback from the arithmetic logic unit (ALU), to a different address from which the next instruction will be fetched.

Many organisations provide free public access to a wireless network.
Explain three ethical, legal or data privacy issues that an organisation should be aware of when allowing this access

Websites – any inappropriate websites ie pornography, drugs, guns,

terrorism etc. e.g. is it acceptable for the organisation to allow access to this

sort of material when you can’t control who is accessing the service?

Time – limit amount of time, they may not want to provide indefinite access

or may want to charge for access after the time limit has expired.

Preventing file sharing and illegal sharing\use of copyrighted materials.

Accountability – identification of users and actions on a network by

preventing anonymous access.

Prevention of illegal activities such as terrorism and fraud.

The responsibility to keep children safe and protected.

Responsibility to keep users (customers) data safe and secure.

Spoofing of websites, phishing. Responsibility of organisation to put some kind of protection in place, eg filtering of known fraudulent sites.

Recording of private messages or details if not encrypted.

Recording of usernames and passwords that the user may also use to access other systems.

Responsibility of organisation to secure their systems from possible attack.

Sales and marketing – providing sales leads to market products.

State four threats that compromise data integrity and state ways that can be used to minimise these threats

State four threats that compromise data integrity

Human error
natural disaster
data transmission errors
software bugs

How threats to data integrity can be minimised:

Backup data preferably on an external storage media
control access to data by enforcing security measures
design user interfaces that minimise chances of invalid data entry
using error detection and correction software when transmitting data over the network
using devices that directly capture data from the source such as bar code readers, digtal cameras, and optical character readers

Your friend wishes to install a wireless network in his office. Explain to him the difference between guided and unguided media

Guided media uses cables to connect to computers whereas unguided media uses waves.

Describe and give an example of one syntax and one logical programming error.

Syntax
• An error that occurs when a command does not follow the expected syntax of the language, e.g. when a keyword is incorrectly spelt
• Incorrect: IF A ADN B Then
• Correct: IF A AND B Then

Logical
• An error that causes a program to output an incorrect answer (that does not necessarily crash the program)
• An algorithm that calculates a person’s age from their date of birth, but ends up giving negative numbers

Explain how the techniques of

(i) verification,
(ii) validation
are used to ensure that the stored data is as accurate as possible.

Dual input of data

Two inputs are compared by the system and any discrepancies are reported (and not stored.)
Data input once, either printed out or checked on the screen and errors corrected

Rules are given to the processor

Only accept A, B, C, D, E, F, G i.e Any other input rejected.

Drop-down list/radio buttons

Provides only valid inputs, so no other validation is required

What is secondary storage?

A non-volatile store of data

Distinguish between microwave and a radiowave transmission and a microwave transmission (KCSE 2017 PP1)

Microwaves can cover shorter distances. On the contrary, radio waves can travel a long distance. Radio wave is usually propagated through sky mode while microwave uses the line of sight propagation.

Satellite services are used to provide broadband internet connectivity to regional and remote areas of Kenya. State one advantage and one disadvantage of using satellites for this purpose.

Advantages

can cover large areas
requires minimal land-based transmission support
requires minimal infrastructure to provide internet access
minimal impact on the environment or humans.

Disadvantages

transmission speeds are not comparable with other forms of transmission
data costs are expensive by comparison to other forms of transmission
expensive to deliver.

State the functions of the following utility programs

(a) Defragmentation software

(b) Disk contents analysis/repair software

(c) Disk formatter

(a) Defragmentation software - Reorganises files on a disk to improve efficiency

(b) Disk contents analysis/repair software - Scans a hard disk to identify bad sectors

(c) Disk formatter - Prepares a hard disk for first use

Describe the main characteristics that distinguish high-level programming languages from low-level languages.

Low level languages do not resemble natural languages they are made up entirely of bit patterns
Low level languages produce code that is executed faster as it is already in a format the CPU can execute / does not need to be translated.
High level languages are easier to understand / learn as commands are more like English / identifiers can be meaningful .
High level languages are easier to use leading to fewer errors.

The following are software classified according to the end user licence agreement. Briefly describe each of them:

open source software, freeware, shareware, and proprietary software

Open source : refers to software provided freely with its source code. The user can modify and redistribute the software.

Freeware: these are software that can be downloaded for free and distributed, buta the source code is hidden and cannot be altered.

Shareware: is software that is available for free within a given trial period, after which it must be bought.

Proprietary: software made for commercial purposes. The source code is hidden, and it can only be used after paying for a licence.

When a new student is enrolled, a new record is added to the file immediately. The examination grades of all students are updated twice a year. Discuss the processing implications of these two requirements.

Enrolment:
- Data input on line
- Individual records validated
- Speed mismatch implications
- Indexes updated immediately
Exam grades:
- Data input twice
- Off line
- Run as a batch
- At otherwise downtime

Give one difference between a compiled program and interpreted program

A compiled program will only execute on a processor of specific type/family/with same instruction set
A program run using an interpreter can execute on a computer with any type of processor;

Name two other input/output devices used at the POS terminal apart from keyboard and barcode reader and give a use for each device.

device: beeper/loud speaker
use: to indicate barcode correctly read/error in reading barcode
device: (LCD) screen/monitor
use: to show prices and other information about goods
device: touch screen
use: to show prices and other information about goods/to select items that need to be
weighed/identified
device: weighing machine
use: to find weight of loose items (e.g. fruit) to enable pricing
device: (magnetic) card reader/CHIP and PIN reader
use: to read customer’s debit/credit card/enable customer to pay for goods using a
credit or debit card
device: printer
use: to print receipts

Give one application of each type of data transmission. Each application must be different

Parallel

sending data from a computer to a printer
internal data transfer (buses)

Serial

connect a computer to a modem

Q&A-KCSE Computer Studies Paper 1

DOWNLOADS:KCSE & JOINT EXAMS

Q&A CRE

Q&A History

Maths Topical

Q&A Sciences

Q&A Mathematics

Q&A Geography

Q&A Computer Studies

Q&A Category

Related Content

Get in Touch

Useful Links

Quick Links

External Links