Any four of:
Sequential:
• Individual instructions are executed one after another
• Flow control is accomplished by jump/branch/goto instructions
• Results are usually achieved less quickly than parallel processing (do
not award twice)
Parallel:
• Individual instructions can be routed to different processors for
simultaneous execution
• Results are usually achieved quicker than sequential instruction (do not
award twice)
• Requires multi-core processors or multiple microprocessors
• Tasks may be split into different parts with each part executed on a
different processor
• Results need to be merged back together after completion

• Radiowaves are omnidirectional while microwaves propagate in one direction at a time(unidirectional)
• Radiowaves can be propagated over long distances through sky mode while microwaves require a relay satellite to amplify and retransmit the microwaves signals to the receiver earth station

• consists of values between 0–255 / 0–FFF
• values are separated by full stops/colons
• it is a unique address
• can be static or dynamic
• can be public or private
• can be IPv4 / have four groups of digits
• can be IPv6 / have eight groups of digits
• in IPv6: can replace groups of zeros.

A PAN exist around a single person whereas a LAN covers a larger area

(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

• A HDD can contain multiple platters (disks);
• A disk/disks that move/spin
• Each platter is divided into sectors;
• The disks are spun at a very high speed (approximately 7,200 rpm to 10,000 + rpm);
• Read\write heads (move across the disk to) read and write data;
• There is one read\write head for each side of a platter ie two heads per platter;
• Data is written to\read from the disk by magnetising\polarising\sensing microscopic regions on the disk;
• Data is organised in concentric rings called tracks;
• There is a small circuit board on the drive that controls the reading and writing of data;
• Data is transferred from and to the disk via a cable/electrical current being passed;
• The intersection of sectors and tracks are called blocks;
• Data is read 1 block at a time

• It has electrical components.
• It is programmable.

• Main memory is transitory/temporary/volatile, secondary storage is (semi-)permanent
• The processor can only use data/instructions that are in the main memory
• Main memory is directly accessible to the processor, secondary storage is not directly accessible to the processor 

Multitasking - the  capability of an operating system to enable users to run two or more programs at once on a single computer

Real time processing - data processing system in which the time interval required to process and respond to inputs is so small that the response itself is useful for controlling the physical activity of a process

Time-sharing processing  - a processing mode in which the central processor serves two or more users with different processing requirements (tasks)

On-line processing - is that type of processing where the result of data processing transaction is available immediately

(i) the potential health hazards of this type of work,

• backstrain due to long periods of immobility
• eye strain due to long periods of staring  at the screen
• RSI- continual use of the same muscle group

(ii) the ways that management can help to overcome the effects of the health hazards.

• Move around regularly
• use ergonomic chair
• use anti-glare screen
• use of wrist pads

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

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)

• 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

• once instructions are given, the processing runs automatically hence requiring little supervision
• tasks are processed as a group hence reducing the cost
• It is faster since the since runs automatically
• there is increased output since the processor works without any interruption

• allowing the network to share resources like files and software for printers and computers
• support the network's implementation of security features
• controls user accounts
• supplies network administrators with network monitoring tools.

• less errors on input
• requires less storage space
• validation
• quicker to input
• quicker to find

• backups/dumps of files
• copy of files on CD/tape streamer
• file generations

• Thesaurus - Is a feature in a word processor that suggest words with the similar or opposite meaning to the one selected
• Comments: a feature in a word processor that allows a user to attach a remark about the selection

• Unfamiliar graphics or quizzical messages appear on the screen
• Programs taking longer than usual to load
• Less memory allowance than usual
• Unusual error messages occurring more frequently

• An end user license agreement (EULA) describes a contract (agreement) between a software developer and a user of that software.