• A non-volatile store of data

1. Virus scanning / Anti-virus. Used to locate and delete viruses / scans and compares files with databases of known viruses.
2. Firewall: checks data packets / examines source address / filters out unexpected packets.
3. Back up. Copies data onto a separate storage device for use if the original data is lost or corrupted.

17. a) i) Explain the term search as used in the Internet.                                            [2]

A web based application that locates items or information from the World Wide Web

ii) Peter intends to download a movie from the Internet. State the three factors that may determine the total time taken to complete the download.                                           [3]

• Size of the video/format
• The bandwidth of the media/speed of network/network traffic
• Type of browser software
• Background activities running in the computer
• Restrictions enforced in the computer/firewall/antivirus
• Speed of the computer/CPU speed
• Size of RAM

b) Wakulima online is an organization that runs a web based system for assisting farmers to obtain market for their produce. State four technological reasons that may cause a farmer not to access the organization’s system.                                                                                  [4]

• Poor network/lack of connection
• Software failure in the system

• Hardware failure
• Lack of access rights
• System overload/hanging
• Lack of skills/disability/illiteracy
• Lack of power supply

c) Explain a situation when each of the following Desktop Publishing program features may be used when creating a publication:

i. Cropping                                                                                                               [2]

Applies to graphics – used to trim/remove/hide some portions in the graphics

ii. Transparency                                                                                                         [2]

Used to make background of a graphic to be clear/visible

d. List two areas where infrared waves are used in data communication.                             [2]

18. a) List four activities of the planning stage of systems development.                             Ignore this question, marks redistributed elsewhere

b) Explain a circumstance when each of the following feasibility studies are carried out during systems development.

i. Technical                                                                                                               [3]

Done to determine whether technology exists to support the proposed solution

ii. Economic                                                                                                              [3]

Done to determine whether the proposed solution is economically viable

iii. Schedule                                                                                                               [3]

Done to determine whether the proposed system can be done within an acceptable time.

c) Table 1 and Table 2 are related tables in a database. Use them to answer the questions that follow.

Table 1

Table 2

i. Identify the appropriate primary key for each table.                    [2]

Table 1 – Dept code, Student Registration No

ii. Explain two benefits of enforcing referential integrity in the database. [4]

• No record can be added in Table 2 if its corresponding record in Table 1 does not exist
• No record in Table 1 can be deleted without first deleting the corresponding record in Table 2
• Reduces data redundancies/ensures integrity
• Prevents deletion of related table

19. a) Describe each of the following validation checks as used in data processing.

i. Preserve check                                                                                                      [2]

Ignore this question, marks redistributed elsewhere

ii. Data type check                                                                                                    [2]

Ensure correct type of data is entered for the field

iii. Check digit                                                                                                           [2]

This is a number added/calculated by the computer to a binary number. The check digit ensures correct transmission of the binary number.

b. Write each of the following abbreviations in full:

i) BCD                                                                                                                                    [1½]

Binary Coded Decimal

ii) EBCD                                                                                                                                 [

This question was thrown out and marks redistributed elsewhere

iii) ASCII                                                                                                                    [1½]

American Standard Code for Information Interchange

c) Using 10-bits binary number system, perform the following decimal operation using two’s complement.                                                                                                                                   [6]

12910 - 12810

+129 = 00 1000 0001

128 = 00 1000 0000

-128 = 11 0111 1111 (ones complement)

                            +1

          11 1000 0000 (Twos complement)

129- 128

     00 1000 0001

+ 11 1000 0000

 100 0000 0001

Hence = 00 0000 00012 or 12 (the overflow bit is ignored)

• To detect and remove errors
• To confirm if the program produces the expected output

• They run only one program/task
• OS would increase development and manufacturing cost as more storage will be needed

– faster communications now widely available
– safety reasons, e.g. increase in terrorist attacks on international flights
– reduced transportation/accommodation/hardware costs
– environmental issues, e.g. reduced carbon footprint
– increase in multinational working

• Phased means that only one part of the system is implemented at a time

• To provide legal backing so that it is possible to seek redress if the rights are violated
• To observe copyright for those who create original works
• To protect the confidentiality of information kept  about an individual

(a)

• Hardware required by each computer to connect to a network is a Network Interface Card / NIC / network adapter

(b)

• Computer A adds computer D’s address to packet
• Computer A sends packet to switch
• Switch looks at address on packet  Switch compares to stored list of addresses on network
• Switch forwards packet to computer D’s address

State the functions of the following protocols

POP -Stands for post office protocol

• used to download emails from email servers

SMTP- Simple Mail Transfer Protocol

• used to send emails to email servers and transfer emails between servers

FTP - Stands for the file transfer protoc

Incremental:

• Only the changes need to be backed up
• The software/OS/settings are unlikely to have changed between backups
• Small number of files likely to be used/edited between backups
• Take less time to backup
• Each backup will take less memory space to store

Full:

• Backup all the data/files and software
• It might not take a significant time to back up entire system
• He might only have a small number of files to be backed up each time
• Safer as have more past versions to revert to
• User may have changed settings on computer
• Faster to restore the backup
• Needs to do a full before he can do an incremental

• to enable logon information to be kept on his computer
• to provide pages customised for Ahmed the next time he logs on
• to implement shopping carts and one-click purchasing
• to be able to distinguish between new and repeat visitors to the website

• Main document
• Data source
• merged document

• Recommendation on whether to continue or abandon the project
• Methods used to collect data
• benefits and limitations expected
• the technology required to develop and maintain the project
• Installation and running cost
• Time limit

ICT is used to create e-commerce platforms that have made business transactions easier and convenient by allowing customers make purchases and payments from anywhere at any time

ICT is used by marketing agents to create exciting multimedia presentations concerning products or services and present them to the target customers using presentation software such MS PowerPoint

Using multimedia, presentation and animation software, it is possible to design attractive advert materials and video clips to display on billboards, broadcast over a television or uploaded on the internet

(a) Disk mirroring- Data is written on two or more disks simultaneously.

(b) Encryption - Contents are scrambled so they cannot be understood without a decryption key

(c) Backup - A copy of the data is taken and stored in another location

Hard disk drive

• to hold the operating system/communication and applications software/ISP software
• for storing files/information/cookies on backing store

RAM

• for data, computer programs and operating instructions which are moved into it/downloaded for data currently in use

DVD writer

• Films/videos/pictures/music/multimedia data downloaded/purchased

Modem

• link/dial up/establish communication with the Internet
• Convert digital signals to analogue/audio tones (and vice versa) Which can travel across the telephone system

• Simple technology is needed to develop both hardware and software.
• Digital devices are more reliable, small in size and use less power as compared to analog devices.
• Devices that read, process or output data in digital form are used in computers and other digital devices such as calculators.

• Distributed data processing is where computers located in physically separate location transmit data after processing to a server computer that updates the master file. Time-sharing on the other hand is where various terminals transmit data to be processed by a central computer's CPU. Each terminal's tasks are allocated a time slice of the CPU