Define the following
(a) Cookies
(b) Spyware
(c) Phishing
(d)Spam
(e) Pharming
(a) Cookies
(b) Spyware
(c) Phishing
(d)Spam
(e) Pharming
State the functions of the following registers
Program counter // PC
• Stores the address of the next instruction to be fetched
Memory address register // MAR
• Stores the address where data/instruction is to be read from or saved to
Memory data register // MDR
• Stores data that is about to be written to memory // Stores data that has just been read from memory
Current instruction register // CIR
• Stores the instruction that is currently being decoded/executed
Give two other uses of hexadecimal in computer science.
There are security concerns associated with cloud storage.
(a) State one way in which providers of cloud storage could prevent security breaches by their own employees
(b) Explain why data on networks is encrypted
(a) One from:
(b) To prevent unauthorised access (1) so that data remains confidential (1) by making it unintelligible (1) because it is scrambled (1)
Computer Studies Paper 1 2021 KCSE Prediction Section B Qs. 17,18 and 19
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]
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]
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
|
Dept Code |
Dept Name |
|
001 |
Computer |
|
002 |
Aviation |
|
003 |
Engineering |
Table 2
|
DeptID |
Student Registration No. |
Student’s Name |
|
002 |
St01 |
Alex Too |
|
003 |
St02 |
Naomi Komi |
|
002 |
St03 |
Peter Kengo |
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]
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)
Elucidate the fact that zero can only be represented in one way in twos complement and in two ways in ones complement
Taking a four-digit 0 binary number i.e (0000)2
In ones complement this is 1111
In twos complement this becomes 1111+1= 0000
So, It is clear that 0 and negative zero is the same in twos complement while in ones complement they are two different values
Explain why a software developer should be responsible for addressing ergonomic issues in software design.
Responsibilities of the software developer is to ensure that the ergonomics focuses on making software user-friendly, reduces repetitive motions or eyestrain and enables movements of users to promote comfort and efficiency.
Software can be designed with adjustable text sizes and screen brightness settings to prevent eye strain, offering users a way to customise their visual experience for better comfort during prolonged use.
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
Disadvantages
Compare and contrast CLI and GUI
CLI
GUI
Comparison
What is the difference between a logical file and a physical file?
What precautions would you take in a computer room in case a user complains of backache after long periods of using the computer?
Ergonomic Chair: Ensure that each user has an ergonomic chair that provides proper lumbar support. The chair should be adjustable in terms of height and backrest angle.
Adjustable Desk: Provide adjustable desks or workstations that can accommodate different user heights and allow for proper positioning of the keyboard, mouse, and monitor.
Monitor Placement: Ensure that the computer monitors are positioned at eye level or slightly below to prevent users from straining their necks and shoulders. Consider using monitor stands or adjustable monitor arms for better positioning.
Keyboard and Mouse: Encourage the use of ergonomic keyboards and mice that are designed to minimize strain on the wrists and hands. Provide wrist rests if needed.
Proper Lighting: Ensure that the computer room is well-lit, with appropriate lighting levels to reduce eye strain. Avoid glare on the computer screens by using adjustable blinds or curtains.
Regular Breaks: Encourage users to take regular breaks from prolonged computer use. Suggest the 20-20-20 rule: Every 20 minutes, look away from the screen at an object 20 feet away for at least 20 seconds.
Stretching Exercises: Promote stretching exercises for the neck, shoulders, and back to help alleviate muscle tension and improve blood circulation. Display posters or provide resources on desk stretches and exercises.
Correct Posture: Educate users about proper sitting posture, emphasizing the importance of maintaining a neutral spine position. Provide visual aids or ergonomic training materials to demonstrate the correct posture.
Desk Organization: Encourage users to keep their workstations organized to minimize the need for reaching or straining. This includes keeping frequently used items within easy reach and arranging cables to prevent trip hazards.
Individual Assessments: If the backache issue persists, consider offering individual ergonomic assessments for users. A specialist can evaluate the user's workstation setup and suggest personalized recommendations.
What characterises a phased implementation approach?
- Phased means that only one part of the system is implemented at a time
Define Data Security
State three types of optical disks
State the symptoms of a computer virus
Describe the role of the registers and system clock within the fetch-execute cycle.
State the functions of the following protocols
POP -Stands for post office protocol
SMTP- Simple Mail Transfer Protocol
FTP - Stands for the file transfer protocol
State the functions of the following protocols
POP -Stands for post office protocol
SMTP- Simple Mail Transfer Protocol
FTP - Stands for the file transfer protoc
Xpat ICT has been tasked to construct a network for an organisation. Explain three factors that the company should consider when selecting the medium for the connectivity (KCSE 2021 Computer Studies Q19c)
Explain, with examples where appropriate, the following five computer terms.
(a) Buffer
(b)batch processing
(c) e-commerce
(d) simulation
(a) Buffer
(b)batch processing
(c) e-commerce
(d) simulation
(e) Email
List three characteristics of Internet Protocol version 6 (IP6).