GIANCHERE FRIENDS COMPUTER STUDIES FORM 4 TERM 1 MID-TERM 2020

GIANCHERE FRIENDS COMPUTER STUDIES FORM 4 TERM 1 MID-TERM EXAMS 2020 and marking scheme

27/2/2020

Instruction to candidates

Write your name and index number in the space provided above.
Sign and write the date of examination in the spaces provided above.
This paper consists of two sections A and B.
Answer all the questions in section A.
Answer question 16 and any other three questions from section B.
All answers should be written in the space provided in the question paper.
This paper consists of 13 printed pages.
Do not remove and pages from this booklet.
Candidates should check the question paper to ascertain that all the pages are printed as indicated and that no questions are missing.
Candidates should answer the questions in English.

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SECTION A: COMPULSORY

QN.1	Define the phrase ‘database management system’ DBMS is a computer program that define, retrieve and manage data in a database

QN.2	What is an internet service provider? ISP is a company/firm authorized to offer internet services to people such companies include: Safaricom Jamii Telecom Aitel Orange Access Kenya Zuku read more

QN.3

Discuss how humidity can be controlled in the computer laboratory

Humidity can be maintained in the computer laboratory through installation of humidifiers and dehumidifiers, proper ventilation to encourage air circulation and proper roofing to control temperature in the computer laboratory.

QN.4	Describe drag and drop as a mouse technique drag means clicking on an object using a mouse, moving the mouse position and dropping it at the expected location.

QN.5	State two limitations of entering data into a computer system using a touch sensitive input device touch screens are delicate to handle and difficult to maintain touch screens are costly user can enter wrong information unknowingly

QN.6 - (a)

State three differences between COM port and LPT port

COM PORT
the com port also called communication port or serial port is unique in the following ways

it is serial (transmits one bit of data at a time)
it is slow in transmission
it is a 9-pin connector
it is BI-DIRECTIONAL meaning that transmission is in either direction

LPT PORT
LPT stands for line printer terminal. this port is also called parallel and has the following uniqueness:

it is parallel (transmit more than one bit of data simultaneously using a set of many conductors)
it is faster in transmission
it is UNI-DIRECTIONAL meaning that data can only move in one direction
has 25 pins

QN.6 - (b)

State three circumstances under which voice input would be preferred over other method of data capture.

Security reasons such as biometric systems
If the computer user is disabled
Voice to Text conversion is a fast way to input data
Ability to minimize errors

QN.7

As Brik was working in his computer, he realized that the program he was running used more memory than the available memory in his computer. Identify the extra memory used by the program and where it is located

The memory is called virtual memory
It is located at the harddisk drive

Virtual Memory

Additional Information

In order to manage memory more efficiently and with fewer errors, modern systems provide an abstraction of main memory known as virtual memory (VM). This is a storage allocation scheme in which secondary memory can be addressed as though it were part of main memory.
The virtual memory is a creation of the operating system and works silently behind the scene. If too many processes need too much memory, then some of them will simply not be able to run. When a program is out of space, it is out of luck. Memory is also vulnerable to corruption. If some process accidentally writes to the memory used by another process, that process might fail or halt.

Functions of the virtual memory

It uses the main memory efficiently by treating it as a cache for an address space stored on disk, keeping only the active areas in main memory, and transferring data back and forth between disk and memory as needed.
It simplifies memory management by providing each process with a uniform address space.
It protects the address space of each process from corruption by other processes.

QN.8

The picture below shows a machine hand drawing a beetle

(a) Identify the machine being used

Plotter

(b) Identify two advantages of the machine over a laser jet printer

Specifically designed to produce vector graphics. It is therefore a special purpose machine designed to produce graphics more efficiently and with a better resolution.
Produces work on a large piece of paper but a laser jet produces work on papers which are A4 or less than A4
A plotter can work on different materials such as paper, piece of clothe, timber, wall and others while a laser jet can only work on a piece of paper.

QN.9

State three Factors to consider when choosing a secondary storage device

CAPACITY
this is the amount of space it can store measured in bytes
PRICE
the cost of purchasing the secondary storage device
WARRANTY
this is an agreement between the buyer and seller spelling terms of using the device
SIZE
this depends on where you will install the device, there are computers such as laptops, desktops, towers and mini-computers. The size of the computer depends on the type of device you will install
TYPE
the are two types of secondary storage devices categorize on where they will fit. PCI (peripheral component interconnect) components are installed in the system unit and external devices are portable devices that can only be used in time of need.
RELIABILITY AND EFFICIENCY
this is the quality of the device and also it's consistency. some devices cannot produce expected results. Reliability and efficiency is identified through a trusted manufacturer, user manual, friends and forums.
TECHNOLOGY
the technology used to manufacture the device can either be optic, magnetic and solid state. Example: solid state technology produce most of portable storage devices while magnetic technology produced PCI bound components and optical produce CDs and DVDs.
Solid state devices are also vulnerable to computer virus as compared to optical disks.
COMPATIBILITY
compatibility is the ability of a secondary storage device to work in its host hardware and operating system. There are two types of Operating systems used widely that is MAC OS and Windows; there are some components meant for either of the operating systems. Operating systems such as Android do not support storage devices that are not portable.
USER-FRIENDLINESS
this is the measure of how comfortable the user can be able to use the storage device. It mostly applies with portable secondary storage devices.

QN.10

State how an operating system handles the following in a computer system
(a) errors

when an error is detected, the operating system will alert the user by displaying an error message and possible ways of correcting it

(b) interrupt

a special program called interrupt handler prioritizes the interrupts and saves them in a queue if more than one is waiting to be handled. A task with the highest priority is first given a chance to execute while others are made to wait and the one that was executing is paused.

QN.11

The diagram below shows a formatted plate surface of a storage disk

Shade and label:
a) One sector
b) One block
d) One track

QN.12

State functions of the following OSI layers

a) Session
provides mechanisms for opening, closing and managing a session between end-user application processes

b) Network
used for routing (packet forwarding and switching)

c) Physical layer
defines the hardware equipment, cabling, wiring, frequencies, pulses used to represent binary signals

QN.13

During database construction, it is necessary to consider field properties for each table field. With relevant examples, state the functions of the field properties listed below

(a) Field size
this is the maximum number of characters that a field should have.
Field size is used to set maximum size for data stored in a field set to the text, number or auto number.
Example: a byte has up to 255 characters.

(a) Input Mask
also called edit field is used to control the values users can enter in a textbox.
Example: to format a telephone number in an input mask will be "(+254"999\999\999\)

QN.14

a) Differentiate between Bcc and Cc as used in emails

BCC means blind carbon copy and CC stands for carbon copy. When an email user sends one email to many people, he/she will enter recipient email addresses to the BCC textbox or CC textbox.
The difference between the two features is that while using BCC, the recipient will be hidden from viewing email addresses of other recipients while CC, all recipients will view all email addresses of other recipients.

b) Discuss real-time processing mode and state how it can be effectively used in a bank

Real-time processing is also called TRANSACTION ORIENTED PROCESSING. It occurs when data is processed at the same time the transaction occurs and files relating to the transaction updated immediately before the next transaction.
Real time processing can be used in a bank to update records while the bank customer withdraws or deposits money. It can also be used for security, temperature control and loan approvals.

QN.15

In relation to DTP, state the purpose of frames

Frames are objects meant for inserting graphics and text into printable area when designing a DTP document. They let users place objects wherever they want on the page.

SECTION B: OPTIONAL

QN.16

Study the flowchart below and answer questions that follow:

(i) Name the control structures used in the flowchart.

Selection
Sequence

(ii) Determine the values of M, N, P and Q.
M=N=P=Q=17

(iii) Write the pseudocode for the flowchart.
Start
M=6
N=17
P=M-N
Q=N+M
IF P>Q THEN
N=M
Q=N
P=M
ELSE
M=N
Q=M
P=N
End IF
Print N,M,P and Q
End;

QN.17

(a) A supermarket uses a computer system which operates in both batch mode and real time transaction mode.

(i) State two task which could use batch processing

Payroll for employees
Monthly, yearly, weekly and dairy reports and summaries
Debits and Credits

(ii) State two task which must be done in real time mode.

Stock control
Security systems
Temperature and humidity control systems
Cash register
Credit cards control systems
Point of sale terminal

b) State three ways in which data loses integrity in an information system
data loses its integrity because of the following reasons:

if it is not accurate
if it not relevant or valid
if it is expired (lack of timeliness)
if it is not complete

c) A school keeps a spreadsheet of examination results in four subjects. Part of the spreadsheet is shown below.

(i) Which column has been used to sort the data?

Column A (names have been arranged alphabetically in ascending order)

(ii) What formula has been entered in cell G2 to calculate Allen’s average mark?

Function
=Average(C2:F2)

Formula
\[=\frac{C2+D2+E2+F2}{4}\]

(iii) The IT results need to be sorted so that the highest mark is at the top. Describe how this sort could be done.

Highlight column G
On the ribbon under 'editing group' click the 'sort'control
On the drop-down options displayed select 'sort largest to the smallest' or 'descending'

(iv) A formula is entered in cell H5, “Pass” appeared as output. What formula has been entered?

Function:
\[=IF(G5> = 50,"Pass","Fail")\]

(v) State the validation check that should be carried out on data entered in cells C2 to F8 to ensure values over 100 are not input.

Highlight cells C2:F8
Click on 'data tab' to display 'data' tools group
Click on 'data validation icon' to display dropdown options, then select 'data validation' command from the options. The data validation window will occur.
On the window under 'allow' option, select
- whole number
- data select 'between'
- minimum select 0
- maximum , type 100 then click ok to apply

(vi) The school has kept the spreadsheets of all the examination results for the last five years. What feature of the spreadsheet software would allow the results to be easily compared?

Macros and Excel VBA

QN.18

(a) Define the following web related terms:

(i) Web browser

a web browser is a computer program which gives internet access to computer users and acts as an interface between the user and the internet by requesting the information that the user wants and interpreting web pages.
Examples: Opera, Google Chrome, Firefox, Safari, Sea Monkey etc.

(ii) Hyperlink

this is a piece of text/image embedded with an address that links a document into another location. It is active when tapped or clicked. Example: Atika School

(iii) Hypertext document

this is a document that contains links referring to other parts of the document

(b) List six activities performed on the web

E-mail services
Banking and Finance
Social Networking
Online gaming and entertainment
E-conferencing
E- Chatting
E-Commerce
VoIP - Voice over Internet Protocol
Auctioning
IoT - Internet of Things
File sharing and downloading
E-Learning
Freelancing
E-Marketing
Dissemination of Information
Cloud Computing

(c) An institution has ten stand-alone computers

(i) Suggest with reasons the most appropriate topology required to inter-connect the computers

Star Topology
- Reasons:
  - easy to maintain and troubleshoot
  - if node fails, it will not affect other nodes
  - easy to reconfigure and upgrade
  - has good false tolerance due to centralized control of nodes
  - it is less expensive to install and maintain

More on topic ...

https://afteracademy.com/blog/what-is-network-topology-and-types-of-network-topology

(ii) State the necessary steps required to connect the computers to the Internet

assemble all internet hardware components such as a router/modem, network media, network card-NIC and PC
prepare software such as
- protocols
- drivers and
- web-browsers
get internet service provider - ISP
configure the system

(d) Below is an email address

Name the parts labeled:
i) , ii), iii), iv)

i) personal identification
ii) host/server computer
iii) top-level domain
iv) country indicator

QN.19

Network software can be divided into Network Operating System (NOS) and Network Protocols

(a) State any four administrative activities of the Network Operating System

ensuring the security of data
provide program testing routines
job scheduling
memory allocation and management
audit trial
error handling and management
input/output handling
resource sharing
interrupt handling
remote communications
distributed processing

the bolded options are the core ones

(b) Differentiate between repeaters and routers

Repeaters

operates at the physical layer
restores, amplifies, re-clocks or otherwise improves a network signal that it receives on one of its ports and transmits the improved signal without buffering or interpreting it.
it is a 2-port device.

Routers

works at the network layer
routes data packets based on their IP addresses
they broadcast data signals
interconnects different networks

More details ...

(c) State any three advantages of twisted pair cable

it is easier to setup and maintain
they are cheaper
not bulky nor heavy

d. Using eight bit two’s complement to perform the calculation below leaving your answer in decimal number 13₁₀ - 38₁₀

e. Convert 257₈ to its equivalent Hexadecimal number

QN.20

(a) Explain how data in a computer system can be secured using:

(i) Password

a password is a secret security code only known to the user that prevents unauthorized access to files and systems. A system is secured once only authorized personnel can be able to access.

(ii) Audit trail

this is a record with a list of log files showing who has accessed a computer system and what operations he or she has performed during a given period of time. They are useful both for maintaining security and for recovering lost transactions and monitoring illegal activities.

(iii) Firewall

a firewall is a device or a software that filters data and information exchanged between different networks by enforcing the hosts network access policy. The main purpose of firewalls is to control accesses to protected networks.

(b) A manager in XYZ Company wishes to replace the current manual system with a computerized one in organisations

(i) Explain the reasons for conducting the following activities in system implementation stage
(a) Staff training

familiarizes the staff with the new system
staff gets the training on how to handles errors and troubleshoot the system ones a problem has been detected
to enhance efficiency

(b) File conversion

the objective of data conversion is to maintain all of the data, and as much of the embedded information as possible
to make files compatible with the new system. This enhances efficiency.

(ii) State three factors to be considered in input requirements specifications stage

data types
volume of data
frequency of data input
user interface

(a) State two circumstances under which the manager may opt to use phased changeover strategy when introducing the system into the organization

it is not costly
gives users sufficient time to learn about the new system
since the system is tested at every stage, there are high chances of detecting errors and eliminating them
high ability to add new features in every stage
allows staff training to be done in every stage

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