Computer Studies Paper 1 Questions and Answers - Lanjet Joint Mock Exams 2023

INSTRUCTION TO CANDIDATES

• This paper consists of two sections A and B.
• Answer ALL questions in section A.
• Answer question 11 and any other THREE questions from section B.

                                                                                                SECTION A

                                                                              Answer All questions in this section

1. Suggest two disadvantages of a notebook computer when compared with a Desktop Computer. (2 marks)
2.  
   1. What is a software suite? (1 mark)
   2. Suggest two advantages of using a software suite. (2 marks)
3.  
   1. Explain the two major types of software. (2 marks)
   2. Give an example of each of the above (2 Marks)
4.  
   1. Explain the term Process Control. (1 Mark)
   2. State two areas where process control is used in industry (2 Marks)
5.  
   1. Give one advantage of serial connection over parallel connection. (1 mark)
   2. Give one advantage of parallel connection over serial connection. (1 mark)
6.  
   1. Explain the term pipelining as used in CPU (1 mark)
   2. Explain How parallel processing work (1 mark)
7. Give two advantages and two disadvantages of display devices (e.g., monitors).  (4 marks)
   Advantages:
   Disadvantages:
8.  
   1. Explain briefly why increasing the main memory may improve the performance (e.g., speed) of a computer system. (1 mark)
   2. Explain the term memory address as used in primary memory (1 mark)
9. Explain the following as used in word processing (3 Marks)
   1. Spell-check
   2. Thesaurus
   3. Macros:
10. Explain the following spreadsheet concepts:
    1. Automatic Recalculation. (1 mark)
    2. What if analysis (1 mark)
11. Suggest two advantages of using presentation graphics software over the traditional chalk-and-talk approach in a school environment
    (2 marks)
12.  
    1. Explain the term workstation as used in a networked environment (1 mark)
    2. What is a server? (1 mark)
13.  
    1. Explain briefly identification and authentication in computer access control. (2 marks)
    2. What is a personal identification number (PIN)? (1 mark)
14.  
    1. Explain the term ergonomics. (1 mark)
    2. Suggest two possible causes of eyestrain when using computers. (2 marks)
15. State Three benefits of telecommuting. (3 marks)
    
                                                                                      SECTION B
                                    Answer question 16 (compulsory) and any other three questions from this section
16.  
    1.  
       1. State and describe three types of error can occur in programming: (3 Marks)
       2. When is a programming language considered structured? (2 marks)
    2.  
       1. The Global Science Museum is not large and can become over-crowded when more than 300 people are in the building. They would like a program that will stop visitors from entering when more than 300 visitors are in the building.
          Design a Pseodocode segment for this problem using a REPEAT loop. You do not have to worry about visitors who leave the building, just those who have entered. (3 Marks)
       2. Identify Three aspects of a good HCI? (3 Marks)
    3.  
       1. Give one advantage of compliers over interpreters (1 mark)
       2. Give one advantage of interpreters over compliers (1 mark)
       3. Explain briefly why the source codes must be translated again if the programmer wants to use the program on a computer with a different platform. (1 mark)
       4. Explain why a programmer may prefer to write code for device drivers using low level languages.  (1 Mark)
17.  
    1.  
       1. With the aid of examples, explain number complements in the Binary number systems  (2 marks)
       2. Outline the benefits of using binary number complementation in computers. (2 marks)
    2.  
       1. Why is binary number system best suited for use in computers? (2 marks)
       2. Convert the following base two number into base ten. (2 marks)
          11.01
       3. Convert the following base sixteen number into base two. (2 marks)
          DEF =
    3. Carry out the following binary arithmetic:
       1. 11 + 10 (1 mark)
       2. 1010.011₂ – 11.0111₂ (2 mark)
       3. 101 – 11 (1 mark)
18.  
    1. Describe briefly the three data processing modes (3 marks)
       1. Batching Processing Mode
       2. Real-time Processing Mode
       3. Interactive Processing Mode
    2.  
       1. Suggest two possible reasons for data preparation errors. (2 marks)
       2. Suggest two possible reasons for data input errors. (2 marks)
    3.  
       1. Distinguish between data validation and data verification. (1 mark)
       2. Give two examples of data verification techniques. (2 marks)
    4. Describe briefly the following data validation techniques
       1. Presence Check (1 mark)
       2. Type Check (1 mark)
       3. Range Check (1 mark)
       4. Control Total Check (1 mark)
       5. Parity Checks (1 mark)
19.  
    1.  
       1. Explain the term search engine (1 mark)
       2. Peter and Mary use the same keyword to search for information. Suggest two reasons why their search results may vary.
          (2 marks)
       3. State one disadvantage of using an e-mail account provided by the Internet service provider (ISP). (1 mark)
    2.  
       1. Explain the term URL (1 mark)
       2. For the URL http://www.csklsc.net/pe/calendar.htm,
          http stands for (1 mark)
          The domain name is (1 mark)
          The top-level domain (TLD) is (1 mark)
          pe stands for (1 mark)
    3.  
       1. Explain the term communication protocol (1 mark)
       2. Explain the following types of communication protocol
          Ethernet (1 mark)
          Token Ring (1 mark)
          TCP/IP (1 mark)
       3. Give Two examples of wireless-based communications channels. (2 marks)
20.  
    1. Describe the role of the systems analyst. (2 Marks)
    2. Describe Two techniques used by the systems analyst in requirements elicitation. (2 Marks)
    3. What is a requirements specification and what does it contain? (5 Marks)
    4. Software development is often said to be an iterative process.
       Describe Two events that might spark an iterative process in software development. (2 Marks)
    5.  
       1. Describe briefly the three basic e-commerce models. (3 Marks)
       2. Apart from parental control, state one other ways of Internet censorship. (1 mark)

                                                                                MARKING SCHEME

                                                                                                  SECTION A
                                                                                 Answer all questions in this section

1. Suggest two disadvantages of a notebook computer when compared with a desktop computer. (2 marks)
   • Difficult to replace or upgrade components inside.
   • More expensive than desktop computers of similar computing power and functions.
2.  
   1. What is a software suite? (1 mark)
      • A software suite is a collection of individual applications sold as a single package.
   2. Suggest two advantages of using a software suite. (2 marks)
      • A software suite usually costs significantly less than purchasing each of the application programs separately.
      • Software suites generally provide ease of use because applications within a software suite normally use a similar interface and have some common features.
3.  
   1. Explain the two major types of software (2 marks)
      • System software.
        System software is a set of generalized programs that control or maintain the operations of the computer and its devices, such as the CPU, communication links, and peripheral devices.
      • Application software.
        Application software is a set of programs that are written for or by users of computer systems to perform specific tasks.
   2. Give an example of each of the above (2 Marks)
      • System software.- Operating systems, Device drivers
      • Application software.- Databases, spreadsheets etc
4.  
   1. Explain the term Process Control. ( 1 Mark)
      • A process control is the automatic monitoring and control of an activity by a computer that is programmed to respond to certain feedback that is inputted from sensor.
   2.  State two areas where process control is used in industry (2 Marks)
      • Physical quantities control in chemical manufacturing process
      • Nuclear rectors where the human labour may be risky to involve
5.  
   1. Give one advantage of serial connection over parallel connection. (1 mark)
      • A long-distance connection is allowed.
   2.  Give one advantage of parallel connection over serial connection. (1 mark)
      • The transmission speed is fast.
6.  
   1. Explain the term pipelining as used in CPU (1 mark)
      • With pipelining, the CPU begins executing a second instruction before it completes the first instruction, which results in faster processing.
   2. Explain How parallel processing work (1 mark)
      • Parallel processing divides up a problem so that multiple processors work on their assigned portion of the problem at the same time.
7. Give two advantages and two disadvantages of display devices (e.g., monitors).   (4 marks)
   Advantages:
   • The time required to obtain the output is fast.
   • Display devices are normally quiet.
     Disadvantages:
   • Output produced is only temporary (i.e., will be lost when the device is turned off).
   • Unsuitable for users with visual impairments.
8.  
   1. Explain briefly why increasing the main memory may improve the performance (e.g.,speed) of a computer system. (1 mark)
      • The computer system can then have more memory space for putting temporary data freely, without the need to clear up the space occupied by unused data.
   2.  Explain the term memory address as used in primary memory (1 mark)
      • A memory address is simply a unique number that identifies the location of a particular byte in memory.
9. Explain the following as used in word processing (3 Marks)
   1. Spell-check
      • Word-processing packages provide checking of spellings facility
   2. Thesaurus
      • It provides synonyms (or words with similar meanings)
   3. Macros:
      • A macro is a character or word that represents a series of keystrokes. The ability to define macros allows us to save a lot of time by replacing common combinations of keystrokes.
10. Explain the following spreadsheet concepts:
    1. Automatic Recalculation. (1 mark)
       • Automatic change of a value in a cell as a result of changes in other cells values associated to the by formulae.
    2. What if analysis (1 mark)
       • Manipulation of values in a spreadsheet so as to see the likely outcome of such action. Used in decision-making. Simulation of situations using spreadsheets.
11. Suggest two advantages of using presentation graphics software over the traditional chalk-and-talk approach in a school environment
    (2 marks)
    • The slides can be displayed on a large monitor or on a projector screen.
    • Multimedia presentations can usually draw more attention from students.
12.  
    1. Expalin the term workstation as used in a networked environment (1 mark)
       • A workstation is a networked computer used to access the contents of the central computer (i.e., the server).
    2. What is a server? (1 mark)
       • A server is the central computer in a network used to manage network resources.
13.  
    1. Explain briefly identification and authentication in computer access control. (2 marks)
       • Identification verifies that a person is a valid user.
       • Authentication verifies that a person is the one he or she claims to be.
    2. What is a personal identification number (PIN)? (1 mark)
       • A personal identification number is a numeric password, either assigned by a company or selected by a user.
14.  
    1. Explain the term ergonomics. (1 mark)
       • Ergonomics is the science of designing equipment and workplaces to maximize the safety, comfort, and efficiency of the people who use them.
    2. Suggest two possible causes of eyestrain. (2 marks)
       • Watching the monitor for too long.
       • Low refresh rate of monitor.
15. State Three benefits of telecommuting. (3 marks)
    • Reduce time and expense spent traveling to the office.
    • Eliminate travel during unsafe weather conditions.
    • Allow a more flexible work schedule.
    • Require less office space, furniture, and so on.
      
                                                                                      SECTION B
                                 Answer question 16 (compulsory) and any other three questions from this section
16.  
    1.  
       1. State and describe three types of error can occur in programming: (3 Marks)
          • Syntax errors are mistakes in the programming language’s keywords or control structures. They show up when the program is being entered.
          • Runtime errors show up when the program is run. The program begins to run but the computer cannot carry out one of the instructions and crashes.
          • Logical errors occur when the program runs but produces wrong results. They show up when the program is being tested.
       2. When is a programming language considered structured? (2 marks).
          Supports
          • Modulation
          • Use of control structures
            If..else (selection)
            While..do (loops)
            Case selection
    2.  
       1. The Global Science Museum is not large and can become over-crowded when more than 300 people are in the building. They would like a program that will stop visitors from entering when more than 300 visitors are in the building. Design a Pseodocode segment for this problem using a REPEAT loop. You do not have to worry about visitors who leave the building, just those who have entered. (3 Marks)
          • set total number of visitors to zero at start of day
          • repeat
          • get entry money from visitor
          • add one to the visitors’ total
          • until visitors’ total is more than 300
          • stop visitors entering
       2. Indentify Three aspects of a good HCI? . (3 Marks)
          • Clear instructions placed appropriately on screen
          • Good use of graphics and colour
          • Creation of a help facility
          • User-friendly error messages
          • User control of route and pace through program.
    3.  
       1. Give one advantage of compliers over interpreters (1 mark)
          • After compilation, the object program can be saved for future use without compilingthe source program again.
       2. Give one advantage of interpreters over compliers (1 mark)
          • Since the program statements are translated and executed one by one, it is easier forthe programmer to know which statement is incorrect.
       3. Explain briefly why the source codes must be translated again if the programmer wants to use the program on a computer with a different platform. (1 mark)
          • Object codes are machine-dependent and they are only executable on the same computer platform where they are translated.
       4. Explain why a programmer may prefer to write code for device drivers using low level languages    (1 Mark)
          • Low levels languages requires little or no translation and makes efficient and fast use of hardware
17.  
    1.  
       1. With the aid of examples, explain number complements in the Binary number systems   (2 marks)
          • Ones complement worked out by switching bits (or derived from subtraction of a digit form the base – two). e.g. one’s complement of 1011₂ is 0100₂.
          • Twos complement worked out by adding 1 to ones complement e.g. twos complement of 1011₂ is 0100₂+1₂=0101₂.
       2. Outline the benefits of using binary number complementation in computers. (2 marks)
          • Only one procedure required to do both addition and subtraction viz addition
          • No need for explicit negative number representation as use of complementation enables representation of negative numbers using whole “positive” numbers              Any two @ 1 mark each.
    2.  
       1. Why is binary number system best suited for use in computers? (2 marks)
          • Convenience:-easy to use with 2 state devices because uses two digits to represent all situations in a computer.
          • No need for explicit negative number representation as use of complementation enables representation of negative numbers using whole “positive” numbers. This saves on storage usage.
          • Multiplication and division achieved by merely shifting the bits e.g. to the left to multiply by 2 and shift to the right divide by 2.          Any two @ 1 mark each.
       2. Convert the following base two number into base ten. (2 marks)
          11.01
          = (1X2¹ ) + (1X2⁰)+( 1X2^-1)+ ( 1X2^-2)
          = 2 + 1 + 1/ 2 +1 /4
          = 3.25
       3. Convert the following base sixteen number into base two. (2 marks)
          DEF=
          • D=13, = 1101
          • E=14, = 1110
          • F=15, = 1111
            = 110111101111
    3. Carry out the following binary arithmetic:
       1. 11 + 10 (1 mark)
           11
          +10
          101
       2. 100101 -11 (1 mark)
          101
          x11
          101
          101
          1111
       3.  
          ¹⁰¹/₁₁ (1 mark)
          

          	1 10101
          11	101    11
          	100    011
          	0100       11

       4. 101 – 11 (1 mark)
             101
             - 11
             - 10             {Each @ 1 mark}
18.  
    1. Describe briefly the three data processing modes (3 marks)
       1. Batching Processing Mode
          • Batching processing modes are operating modes that execute a queue of jobs and return the results all at one time. e.g., Printing payrolls at the end of each month, and printing academic result reports of students at the end of each semester.
       2. Real-time Processing Mode
          • Real-time processing modes are operating modes that respond to input data and transactions immediately. e.g., A ticket reservation system in a cinema, and a search engine web site responding to users’ queries.
       3. Interactive Processing Mode
          • Interactive processing modes are operating modes that communicate with the computer users interactively. e.g., Video game playing machines, and computer terminals at bank counters.
    2.  
       1. Suggest two possible reasons for data preparation errors. (2 marks)
          • The data on the original document is interpreted incorrectly.
          • The data on the original document is copied incorrectly (i.e., transcription errors).
       2. Suggest two possible reasons for data input errors. (2 marks)
          • Typing mistakes made by data-entry operators.
          • Entering data items incompletely.
    3.  
       1. Distinguish between data validation and data verification. (1 mark)
          • Data validation is a process of checking data before processing to ensure that the data is correct.
          • Data verification is a process of checking if the data entered is consistent to the source data.
       2. Give two examples of data verification techniques. (2 marks)
          • Enter the data twice by the same operator and then compare the two data sets.
          • Enter the data independently by two different operators and then compare the two data sets.
    4. Describe briefly the following data validation techniques
       1. Presence Check (1 mark)
          • Presence checks determine if data is entered into specified fields.
            e.g., Check if the user name is entered in a membership login form.
       2. Type Check (1 mark)
          • Type checks determine if the different pieces of data input are of specific data types.
            e.g., Check if the NAME field contains alphabets only.
       3. Range Check (1 mark)
          • Range checks determine if the values entered fall within specific ranges.
            e.g., Check if the data entered in the EXAM field fall within the range from 0 to 100.
       4. Control Total Check (1 mark)
          • Control total checks determine if the amounts of data entered are correct by comparing the manually calculated totals with the computer-calculated totals.
            e.g., Calculating the total test scores of students.
       5. Parity Checks (1 mark)
          • Parity checks determine if the binary data transmitted through communication channels is corrupted, by counting the number of bit 1’s in each signal (including the parity bit at the end).
19.  
    1.  
       1. Explain the term search engine (1 mark)
          • A search engine is a program used to search for information on the Internet.
       2. Peter and Mary use the same keyword to search for information. Suggest two reasons why their search results may vary. (2 marks)
          • They may be using different search engines.
          • Some relevant sites may be added or removed.
          • Time causes
       3. State one disadvantage of using an e-mail account provided by the Internet service provider (ISP). (1 mark)
          • The e-mail account can only be used as long as the client is still subscribing to the ISP’s services.
    2.  
       1. Explain the term URL (1 mark)
          • Uniform Resource Locator. It defines the route to a file on the World Wide Web (WWW).
       2. For the URL http://www.csklsc.net/pe/calendar.htm,
          http stands for (1 mark)
          • HyperText Transfer Protocol.
            The domain name is (1 mark)
          • www.csklsc.net.
            The top-level domain (TLD) is (1 mark)
          • net.
            pe stands for (1 mark)
          • a subdirectory name on the server.
    3.  
       1. Explain the term communication protocol (1 mark)
          • agreed-upon and established standard, and in this way all manufacturers of hardware and software that are using the protocol do so in a similar fashion to allow for interoperability.
       2.  Explain the following types of communication protocol
          Ethernet (1 mark)
          • Is based on a bus topology. Each node attempts to transmit data when it determines the network is available to receive communications. If two computers on an Ethernet network attempt to send data at the same time, a collision will occur, and the computers must attempt to send their messages again.
            Token Ring (1 mark)
          • Is based on ring topology . Specifies that computers and devices on the network share or pass a special signal, called a token, in a unidirectional manner. Device with the token can transmit data over the network. Only one token exists per network. This ensures that only one computer transmits data at a time
            TCP/IP (1 mark)
          • Network standard for Internet communications. computer sends data over the Internet, the data is divided into packets. Each packet contains the data, as well as the recipient (destination), the origin (sender), and the sequence information used to reassemble the data at the destination. Each packet travels along the fastest individual available path to the recipient's computer via communications devices called routers.
       3. Give Two examples of wireless-based communications channels. (2 marks)
          • Microwaves -are high-frequency radio waves that are sent through the atmosphere and space.
          • Cellular Radio - is a form of broadcast radio that is used widely for mobile communications, specifically wireless modems and cell phones
          • Infrared - is a wireless transmission media that sends signals using infrared light waves. Infrared transmission requires a line-of-sight transmission and short distances under a few hundred metres
          • Broadcast radio- is a wireless transmission medium that distributes radio signals through the air over long distances such as between cities, regions
20.  
    1. Describe the role of the systems analyst. (2 Marks)
       • A systems analyst observes, clarifies and models an existing system; with a view to improving it through computerisation.
    2. Describe Two techniques used by the systems analyst in requirements elicitation. (2 Marks)
       • Interviewing those involved with current system;
       • Observing how the current system operates;
       • Identifying the data requirements and the data flow of the current system.
    3. What is a requirements specification and what does it contain? (5 Marks)
       • A system specification is the document that results from (the requirements elicitation in) the design stage.
       • It contains a clear problem specification,
       • The system inputs
       • The system outputs
       • Any set assumptions, limitations.
    4. Software development is often said to be an iterative process.
       Describe Two events that might spark an iterative process in software development. (2 Marks)
       • A new requirement from the person who commissioned the software;
       • A new requirement within the current operation (eg a change in law);
       • A new technological development that the software commissioner wants to incorporate;
       • An error in a previous stage of the software development process.
       • Any change or error correction must be taken right back to first stage to check that the design is still correct and valid because finding errors at later stages in the process is very expensive.
    5.  
       1. Describe briefly the three basic e-commerce models. (3 Marks)
          • Business-to-consumer (B2C) e-commerce consists of the sale of goods to the general public.
          • Consumer-to-consumer (C2C) e-commerce occurs when one consumer sells directly to another, such as in an online auction.
          • Business-to-business (B2B) e-commerce consists of businesses providing goods and services to other businesses.
       2. Apart from parental control, state one other ways of Internet censorship. (2 marks)
          • Legislation by the government.
          • Self-regulation by Webmasters.