Computer Studies Paper 1 Marking Scheme
KCSE CLUSTER TESTS 23
Computer Studies Paper 1
SECTION A (40 Marks)
To access records of books and other library materials much faster.
To keep updated records of books and material in the library.
To search titles of books for someone to borrow.
To carry out research in cases where there is connectivity.
2 marks
i) HTML is static-content created with it does not change.
ii) Cannot be used alone when it comes to developing a functional website.
2 marks
One of the functions of an operating system is to prevent deadlock situations.
Explain one situation that can cause a deadlock to occur. (4 marks)
A deadlock is an undesirable situation or stalemate that occurs when two or more processes are holding
common resources, and each waits for the other to release their resources.
An example of deadlock is where process I has been allocated non-shareable resources A,
e.g., a disk drive, and process 2 has been allocated non-sharable resources B,
e.g., a printer. Now, it it turns out that process
I needs resources B (printer) to proceed and process
2 needs resource A (the disk drive) to proceed and these are the only two processes
in the system, each has blocked the other and all useful work in the system stops.
4 marks
Using well labelled diagrams, explain the two types of data signals. (3marks)
Analog signal is made up of continuous varying waveform while digital is made up
of noncontinuous discrete waveform. A ward mark½ for each explanation: 2x½=1mark.
A ward ½ marks for each well drawn diagram: 2x½=1mark
A ward ½ marks for each well drawn diagram: 2x½=1 mark
3 marks
(a) One of the challenges that computer organizations face unauthorized.
Distinguish between logical access and physical access.
(2marks Logical access is ability to interact with data software in the
computer through access control procedures such as identification,
authentication while Physical access refers to the ability of the people to physically gain
access to a computer system or the room where computers are Setup
(b) State one way in which each of the above types of unauthorized to
computer systems can be controlled. (2marks) Logical acces
Use of passwords for computer systems, individual files or folders.
Use audit trails and access logs.
Encrypt data.
Use firewalls. Physical access can be controlled by:
- Burglar proofing. This can be done by fitting the windows, doors,
the roof and any weak access point with grills.
This will deter forceful entry into the room,
- Security alarm system.
- This can be done by installing security alarm systems.
- Employment security guards to monitor those entering the computer rooms.
(A ward 1 for correct answer =1 mark)
5 marks
By citing examples, identify FIVE formatting features used in the above passage.
- Alignment (centre) for the title.
- Justified alignment in the second paragraph.
- Numbering in the last two paragraphs.
- Fonts –double Underline for the word replicates
- Fonts-Bolding the words virus and disc.
- Font-Italicing the words virus and disc
- Indentation-hanging paragraphs for the last two paragraphs.
- Borders-text has a border.
- Shading –text has background shading.
5 marks
- Laptop can use its battery power for a while thus can be
charged and used even when there is no electric power.
- Laptop is easily portable.
- They are designed to withstand vigorous travelling.
2 marks
With aid of an example, describe the embedded computer?
- Embedded computers are computers that are a part of a machine or device.
- Embedded computers generally execute a program that is stored in non-volatile
memory and is only intended to operate to operate a specific machine or device.
- Embedded computers are typically required to operate continuously without being
rest or rebooted, and once employed in their task, the software usually cannot be modified.
o Examples: An automobile may contain a number of embedded computers;
a washing machine and a DVD player. Award ½x2
1 marks
- Fifth generation computers possess Artificial Intelligence characteristics
lacking in fourth generation computers.
- Fifth generation computers have high speed logic and memory chips than fourth generation computers.
- Fifth generation computers can perform parallel processing.
2 marks
(a) Name any TWO types of non-printable guides in DTP. (1mark)
- Ruler guides.
- Column guides.
- Margin guides.
(b) Explain the functions of each of non-printable guides in (11) (a) above
- Ruler guides: Lines that are used to align text and graphics in the correct
position on printable area or the paste board.
- Column guides: helps to divide a given page into a number of columns e.g. as used in a newspaper.
- Margin guides: They define the printable area such that any text or
graphics outside the margin guides will not be printed.
3 marks
(i) Refresh button is used to reload a web page after failure in the current attempt.
(ii) Home button takes the user to the first page (the home page) of the default website.
(iii) History button displays the websites that were visited in the recent past
3 marks
(a) Differentiate between absolute and relative cell referencing. (2marks)
Absolute referencing is a method of referring to a cell such that constant values can
be copied across a group of cells this reference always refers to cells in a specific
location of the worksheet cell if they are copied from one cell to another while Relative cell referencing is
a method of referring to a cell such s that a formula copied a cross a group
of cells changes relative to position of each cell into which it is copied.
(b) The formular $A$4 +C$5 is typed in cell D4 and copied to cell H6
.Write down the formula as it would appear in cell H6. (2marks)
=$A$4+G$5
4 marks
Data verification is the process of checking that data is correctly transcribed while data
validation is the process of checking that data entered at input .
2 marks
(a) (i) Diskette
(ii) Zip Disk
(iii) Compact Disk
(iv) Magnetic tape.
(b) Diskette has less storage capacity (1.4 MB)
while Magnetic tape has more storage capacity in GB.
3 marks
(a) What is a speech input? It is a type of input where a microphone connected to a
computer system is used to enter data in form of spoken words into the computer.
(b) State one advantage and one disadvantage of using this kind of input .(2 marks)
Advantages.
- Voice input is fast.
- Its suitable for people with special needs especially those with impaired hands.
- Can be used in emergency situations.
1 marks
SECTION B (60 Marks)
(a) -Sequence.
-Selection.
-Iteration (looping)
(b) NOTE: 1.It is assumed that the student does six subjects.
2: The output required is: average score and total marks.
(c) –Analog data is continuous in nature, while digital data is in discrete form.
(d) –computers process data faster than devices such as typewriters and calculators.
-Computers are more accurate:-give the correct instruction and data.
Computer produces more accurate results.
They are also able to handle numbers with many decimal places without rounding off.
- Computers are more efficient:-computers require less effort to process
data compared to human being and other machine.
15 marks
(a) Explain the role of problem identification in system development. (2marks)
The role of problem identification stage is to identify the real problem of an existing system. A ward 2x1=2 marks.
(b) Distinguish between a primary key and a foreign key as used DBMS. (2marks)
A primary key is a unique key that can uniquely identify each row/record in afile/table while
a foreign key is a field in a record that points to a key field in another table. (A ward 2x1=2 marks)
(c) (i) State TWO characteristics of a good database/file design. (2marks)
- Divides the information into subject-based tables to reduce redundant data.
- Provides the program with the information it requires to join the information in the tables together as needed.
-Helps support and ensure the accuracy and integrity of your information.
- Accommodate your data processing and reporting needs. (A ward 1x2=2marks)
(ii) Differentiate between phased and parallel implementation methods. (2marks)
In parallel conversion, both the old and the new system are operated until the
project development team and end user management agree to switch completely
over to the new system while in phased conversion only a few departments,
branch offices, or plant locations at a time are converted.
(d)(i) Using appropriate examples, differentiate between distributed and centralized processing modes. (3marks)
Centralized processing is the type of processing where processing is controlled through a central terminal server(s),
which centrally provides the processing, programs and storage while in distributed processing
refers to the type of processing where computers in various geographical locations are
interconnected via communication links for the purpose of local processing and data access and/or transfer.
In distributed processing data processing occurs on each of the computers,
unlike a centralizes processing system in which terminals are connected to
host computer that perform all of the data processing. A ward 2x1=2 marks
(ii) State TWO advantages and TWO disadvantages of each of the processing modes in 17
(d)(i) above. (4 marks) Centralized processing:
Advantages:
Lack of duplication of resources.
Ease in enforcement standards, security.
Economy for equipment and personnel. (Any 2 correct award ½x2=1 mark)
Disadvantages
Slow response time if the terminals are many.
In the event of network failure terminals may lose access to the terminal server. (Any 2 correct award ½x2=1 mark)
Distributed processing
Advantages:
Quicker response time.
Improved data integrity. Resource sharing. (Any 2 correct award ½x2=1 mark)
Disadvantages
Network failure paralyses operations.
Vulnerable to security threats.
Costly software. (Any 2 correct award ½x2=1 mark 18.
(a) (i) M-Operating system.
(ii) N-Application software programs.
(b) Advantages of N in organization Accept.
- Easy to install and run.
- Thoroughly test/few errors.
- Readily available in market.
- Less expensive.
- Easily modified to meet specific need. (A ward 1 mark for any 2)
(c) Classification of program M.
- No. of users.
15 marks
(a) (i) M-Operating system.
(ii) N-Application software programs.
(b) Advantages of N in organization
Accept. - Easy to install and run.
- Thoroughly test/few errors.
- Readily available in market.
- Less expensive.
- Easily modified to meet specific need. (A ward 1 mark for any 2)
(c) Classification of program M.
- No. of users.
- No. of tasks.
- User interface. (A ward 1 mark each)
(d) Situations of use of questionnaire.
Sensitive data.
Tense environment.
Area geographical sparsely populated. (a ward 1 mark each)
(e) –Backups –files stores data to be used security to restores
marginal documents when original is damaged
-Reference files-stores data for future back up purposes.
(f) –One to one. -One to many. -Many to many. -Many to one.
15 marks
(a) A computer diskette in drive A has folders for MEMOS for an administrator. Each of these
folders is labelled according to the relevant months. The secretary created the folders for each
month’s memo for ease of access. Study the table below.
Assuming that the secondary was working from the diskette, draw the corresponding tree structure. (6marks)
(b) (i) The secretary wanted to create a folder to store a memo in Fraud folder. State the path folder. (2marks)
A: /MEMO2/Fraud. (Award 2 marks)
(ii) Suggest how the secretary can ensure that the work in the diskette is not spoilt. (1mark)
do not drop the diskette down.
don’t put heavy objects on top.
don’t put near magnets.
don’t remove from drive when still being read/written.(A ward 1 mark each)
(iii) Suggest how the file is made not viewed by any other person apart from her. (1mark)
Use of password.
(c) (i) List any TWO devices under the control of the operating system. (2marks)
I/Oc
CPU.
Memory.
Secondary storage.
Communication &ports. A ward 1 mark each.
(ii) From questions 19(c)
(i), explain how each of these devices are controlled by the OS. (2 marks)
Supervises transfer of characters between CPU and I/O devices.
Schedules, controls and monitors jobs submitted for execution.
Gives the user an indication of used or free memory.
Responsible for storing and retrieving information from storage devices.
Establishes a standard means of communication between users and computers. (A ward 1 mark each)
15 marks