State three documents that are used during mail merging in word processing
State the uses of 3D printers
(b) The computer needs an operating system and utility software.
(i) The operating system controls the scheduling of processes.
Describe how the operating system uses scheduling to allocate processor time.
State and explain characteristics of an algorithm
Input : An algorithm can take 0 or more inputs well defined outputs
Finiteness: an algorithm must terminate in finite time and after finite number of steps.
Definiteness : an algorithm must be clear and unambiguous. Each and every step of an algorithm must be clear and precise and it must have only one meaning
Feasibility: should be feasible with the available resources
Output : must produce at least one well defined output
Independent : should have a step-by-step directions which is independent of any programming language
Correctness: should solve the problem it is designed to solve
Efficiency: must take the shortest time possible to run and should require the least memory space. It should use a minimum number of computation steps and memory to produce the desired output. takes little time and memory to run
Generality: should not be limited to a specific case. It should work for all the valid inputs. works for many possible inputs
Effectiveness : should statements that are relevant to the problem. Every step must be basic and essential.
What is an Operating System?
1. State two ways in which a computer may be used in a healthcare sector other than record keeping
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)
List Three file organisation methods in a computer
State advantages of hardcopy output
State two ways of protecting computers against viruses.
Explain why smoke and dust particles are harmful to a computer
Overheating: Smoke and dust particles can accumulate inside the computer's casing, blocking airflow and hindering the cooling mechanisms of the computer. This can lead to overheating of the internal components, such as the CPU and graphics card. Overheating can cause system instability, performance degradation, and even permanent damage to the hardware.
Component Malfunction: Smoke and dust particles can settle on electronic components, such as the motherboard, memory modules, and connectors. Over time, this accumulation can create a layer of debris, leading to poor electrical contact and interference with signal transmission. This can result in component malfunctions, intermittent failures, or even complete hardware failure.
Short Circuits: If smoke or dust particles contain conductive materials, such as metal flakes or moisture, they can create a risk of short circuits. When conductive particles come into contact with exposed circuits or connectors, they can cause a direct electrical connection between two points that are not intended to be connected. Short circuits can damage components, disrupt data transmission, and even pose a fire hazard.
Increased Maintenance Requirements: Smoke and dust particles can increase the frequency and complexity of computer maintenance. Accumulated dust can clog cooling fans, causing them to work less effectively or even fail. Additionally, smoke particles can leave behind sticky residues that further attract dust, making the cleaning process more challenging.
Reduced Performance and Reliability: As smoke and dust particles accumulate within the computer, they can restrict the movement of mechanical components, such as fans or disk drives, affecting their performance and reliability. Dust particles can also hinder the reading and writing capabilities of optical drives or cause errors in data transmission.
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)
Identify and describe four roles of the operating system when managing the resources of a personal computer.
Manages memory (RAM)
Ensures programs/data do not corrupt each other: Ensures all programs and data including itself is stored in correct memory locations
Manages processes: Ensures different processes can utilise the CPU and do not interfere with each other or crash •
Allows a user to run programs : On a multi-tasking O/S ensure that all tasks appear to run simultaneously
Describe four features of the operating system when providing a graphical user interface on a personal computer. Give a suitable example of each feature.
Give one difference between a compiled program and interpreted program
Apart from the user interface, name three other components that make up a typical expert system.
– knowledge base
– rule(s) base
– inference engine
– explanation system
– (expert system) shell
State three features of the fifth generation computers (3mks) [2017 paper 1]
Describe two benefits of using USB connections between a computer and a device.
Differentiate between modulation and demodulation as used in data communication
Modulation refers to the process of converting a digital signal to analog signal at the transmission end while demodulation is to converting analog signal to digital signal at the receiving end
Define the term variable as used in programming
A variable is a memory location used to store a value