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
State two computer-based careers that have arisen as a result of computer-based data processing in a factory (2 marks)
System analyst
Web designers
Network administrators
Database administrators
Programmers
Computer technicians
Describe the purpose of two registers that are used by Von Neumann architecture.
MAR( memory address register)
MDR or memory data register
Program counter
Accumulator
Give one reason why use of video-conferencing has increased over the last ten years.
– faster communications now widely available
– safety reasons, e.g. increase in terrorist attacks on international flights
– reduced transportation/accommodation/hardware costs
– environmental issues, e.g. reduced carbon footprint
– increase in multinational working
State five functions of network operating system
Distinguish between Incremental and Full backup
Incremental:
Full:
What is a network server?
Describe four features of the operating system when providing a graphical user interface on a personal computer. Give a suitable example of each feature.
Windows for example a word processing application and a spreadsheet
Menus, for example, allow the user to perform operations or run applications such as right-click to create a new folder
Icons for example a picture of linked computers for networking
Pointers(mouse or touchscreen) for example to select items/trigger events
Shortcuts for example to frequently used applications for example having a shortcut to your mail client on your desktop
File navigation for example when searching the hard disc for a file/folder using a browser
copying / deleting / moving/sorting/naming/searching of files or folders for example copying of a file from the hard drive to a USB pen drive (File handling)
Desktop customisation for example changing the colours and background image
Copy and paste for example between applications e.g. copying a graph from a spreadsheet to a word processor
Error messages for example provide users with error/warning/help messages for example ‘printer out of paper’
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)
Explain the Fetch – Execute cycle and provide an example of a Central Processing Unit (CPU) component for each stage of the cycle
The Fetch – Execute cycle is a sequence of actions, performed by the processor as it fetches
a program instruction from its memory, determines what the instruction wants to do and
carries out those actions. The stages of the cycle are provided below.
Computer Studies Paper 1 KCSE 2021 Prediction
Section A
1.State two reasons for the increased use of laptop computers in government offices. [2]
They are small and fit in a small storage space
They are light weight hence can be carried to areas where their services are required
The monitor, system unit, keyboard units are integrated together
Easy to share
Have rechargeable battery
Have low power consumption
2.Computer network technicians prefer to use command-line based operating systems when configuring networks. State three reasons for the preference. [3]
Do not take up a lot of memory
Have direct access to most hardware devices/provide complete control during configuration
Cheaper to acquire as some are freeware/shareware
Faster to execute commands
Difficult to hack/more secure
More stable
3.State three measures that should be put in place in a computer laboratory to safeguard users’ health. [3]
4.State three ways in which barcode readers may be used in schools. [3]
Take inventory of items
Transactions in the school library
Keep track of movement of goods
Track students in and out of school
Used to register roll call
5.State three advantages of flat panel monitors over cathode ray tube monitors as used in computers. [3]
6.State three possible reasons for the extinction of daisy wheel printers in the market. [3]
7.State three ways in which an operating system secures a computer system. [3]
8.A law firm prefers to use hard copy output when handling documents for legal matters. State two reasons for this preference. [2]
9.State the function of each of the following feature in a word processor
a. Thesaurus [1]
Feature that suggests words with similar or opposite meanings to the selected word
b. Comments [1]
Feature that allows a user to attach remarks
10. With the aid of an example, explain the term multi-level list as used in word processing. [3]
Formatting style that shows listed items at different level instead of using one line
11. Distinguish between real-time operating system and distributed operating system. [3]
Accept answers based on data processing concept
12. Explain the function of protect sheet feature in a spreadsheet program. [2]
A tool/feature that prevents unwanted changes to the spreadsheet. Requires a user to key in a password inorder to make changes
13. State four computer based careers introduced as a result of computerized data processing method at the airport. [2]
NB/ Accept any computer based career
14. In a spreadsheet, the formula = If(A1>10,A1*77,A1*50) is entered in a cell. Interpret the results. [3]
Checks the value in cell A1if it is more than 10, if the comparison is true then the outcome of the value in cell multiplied by 77 is displayed, else if it is false the results of the value in cell A1 multiplied by 50 are displayed.
15. State a stage in systems development cycle where each of the following activities are carried out:
a. Identifying the technologies that may be used in a proposed system. [1]
Accept any sub stage within system analysis e.g. requirement specification, problem definition, information gathering, etc
b. Identifying shortcomings of a system. [1]
All stages of system development
c. Preparing the system migration plan. [1]
Implementation stage
Explain the difference between main memory and secondary storage.
Aeroplanes now use Global Positioning Systems (GPS) to determine their location.
Describe how the computer on board the aeroplane uses GPS to find its exact location
Give two benefits of using GPS in this application
Describe how the computer on board the aeroplane uses GPS to find its exact location
– satellites transmit signals to onboard computers
– computers receive/interpret these signals
– system depends on very accurate timing/use of atomic clocks
– each satellite transmits data indicating location and time
– computer in aeroplane calculates location based on at least three satellites
– at least 24 satellites in operation at any one time
– position accurate to within one metre
– can also calculate altitude of aeroplane
– ref to “triangulation”:
Give two benefits of using GPS in this application
– safer as the known location is exact/more accurate
– reduces the possibility of pilot error
– allows accurate estimation of arrival time
– display and guide the pilot to the nearest airport in case of emergency
Outline any 2 Examples of wireless transmission media (2marks)
Give two reasons why some microprocessor controlled devices do not require an operating system
Describe a typical situation that requires the use of:
(i) a high-level language
(ii) a low-level language.
High level languages are used in situations when:
Low level languages are used in situations when:
Jane has noticed the following problems with her computer (2mks)
State three possible causes of these problems and how they can be solved (3mks)
There could be several possible causes for the issues Jane is experiencing with her computer keyboard, including:
1. Software Issues
- Cause: Outdated or corrupt system files, drivers, or operating system.
- Solution:
- Ensure the operating system and drivers are up-to-date.
- Run a system file checker to repair any corrupted system files (e.g., on Windows, run "sfc /scannow" from the Command Prompt).
- Consider reinstalling the operating system if issues persist.
2. Hardware Issues:
- Cause: Physical damage or malfunction in the keyboard hardware.
- Solution:
- Check for physical damage or debris under the keys and clean the keyboard if necessary.
- If cleaning doesn't help, consider replacing the keyboard with a new one.
3. Resource Overload:
- Cause: The computer may be running too many background processes or lacking sufficient hardware resources.
- Solution:
- Close unnecessary background applications and processes to free up system resources.
- Consider upgrading the computer's RAM, CPU, or storage if it's outdated and unable to handle current software demands.
- Use task manager or activity monitor to identify and terminate resource-intensive processes.
4. Malware or Viruses:
- Cause: Malicious software can slow down a computer, cause hanging, and delay startup.
- Solution:
- Perform a full system scan using reputable antivirus or anti-malware software to remove any threats.
- Ensure that the operating system's security patches are up-to-date.
5. Disk Fragmentation:
- Cause: Fragmented files can slow down the loading of applications and overall system performance.
- Solution:
- Run a disk defragmentation tool (e.g., Windows' built-in tool) to optimize file storage on the hard drive.
- Consider upgrading to a solid-state drive (SSD) for faster application loading times.
6. Insufficient Storage:
- Cause: If the hard drive is nearly full, it can cause slow performance.
- Solution:
- Free up space by deleting unnecessary files and programs.
- Consider upgrading to a larger capacity hard drive or SSD if storage space remains an issue.
7. Background Processes and Startup Items:
- Cause: Too many unnecessary programs running in the background or starting up with the computer.
- Solution:
- Disable or remove unnecessary startup items and background processes to improve startup time.
- Use the Task Manager or System Preferences (on macOS) to manage startup items.
It's important to diagnose the specific cause of the issues Jane is facing by troubleshooting each potential problem one by one. In some cases, a combination of these solutions may be necessary to fully resolve the problems with her computer keyboard.
State two functions of utility software
State the difference between radio waves and microwave transmission