Distinguish between firmware and device drivers as used in computers. (2mrks)
State the functions of the following utility programs
(a) Defragmentation software
(b) Disk contents analysis/repair software
(c) Disk formatter
(a) Defragmentation software - Reorganises files on a disk to improve efficiency
(b) Disk contents analysis/repair software - Scans a hard disk to identify bad sectors
(c) Disk formatter - Prepares a hard disk for first use
451/1
COMPUTER STUDIES
PAPER 1
THEORY
DECEMBER 2021
TIME: 2 HOURS
FORM TWO END OF TERM TWO 2O21 EXAM
451/1
COMPUTER STUDIES
PAPER 1
THEORY
TIME: 2½ HOURS
INSTRUCTIONS TO CANDIDATES:
State email protocols
Describe the role of the registers and system clock within the fetch-execute cycle.
state two advantages of using a pseudocode during program design
State the areas where infra-red radio waves are used KCSE 2018
(b) Routers have an important role in how the internet functions.
Describe how a router directs data on the internet.
Name three of the stages in the system life cycle
– fact finding
– feasibility study
– analysis
– design
– testing
– documentation
– implementation/changeover/installation
– evaluation
– maintenance
State the function of a router in a network
Using an example, explain a difference between a primary key and a foreign key in a relational database.
A primary key is a table field that uniquely identifies each record and ensures that duplicate entries are not allowed
A foreign key is primary key of a parent table placed in a child table to ensure that any record added to a child table is related to the one in parent table.
A foreign key is a field (or a set of fields) in one table that refers to the primary key of another table. It is used to establish and enforce a link between the data in the two tables, ensuring referential integrity.
A school has 3000 students sitting final examinations.
Each student sits eight examinations.
Write an algorithm, using pseudocode or a flowchart, which:
• inputs the marks for all 8 examinations for each student
• outputs for each student the average mark for their 8 examinations
• outputs the highest mark overall
highest = -1
for student = 1 to 3000
total = 0
for exam = 1 to 8
input mark
total = total + mark
if mark > highest then highest = mark
next
average = total/8
output average
next
output highest
Python code:
highest = -1
for student in range(1, 3001):
total = 0
for exam in range(1, 9):
mark = int(input("Enter mark: "))
total += mark
if mark > highest:
highest = mark
average = total / 8
print("Average:", average)
print("Highest mark:", highest)
VBA Code
Option Explicit
Sub CalculateAverageAndHighest()
Dim highest As Integer
Dim total As Integer
Dim mark As Integer
Dim average As Double
highest = -1
For student = 1 To 3000
total = 0
For exam = 1 To 8
mark = InputBox("Enter mark:")
total = total + mark
If mark > highest Then
highest = mark
End If
Next exam
average = total / 8
MsgBox "Average: " & average
Next student
MsgBox "Highest mark: " & highest
End Sub
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)
The Acme company stores data for a private scientific research group. It has recently upgraded its storage capacity and needs to dispose of its existing hard drives securely. Outline two methods for the secure disposal of the data on the hard drives.
Acme company needs to ensure that if they are reselling the drives they wipe the drive (this should be done regardless of the destruction of the drive) to the DoD standard.
This would ensure that any software cannot be used to locate files.
Suggest one disadvantage to the programmer of using a high-level language instead of a low-level language.
State three factors to consider when selecting an operating system to install in a computer (3 marks)
Identify which processor in the PC systems below is likely to process instructions more efficiently. Justify your answer.
List two primary functions of a domain name server.
Differentiate between Physical and logical topologies