KCSE 2011 Computer Studies Paper 1 Questions with Marking Scheme

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Computer Studies Paper 1 (451/1)

SECTION A (40 marks)
Answer all the questions in this section in the spaces provided.

  1. The text in the box below was composed using a wordprocessor. The current cursor position is between the words is" and "an".
    Computer security is an increasingly important
    consideration. From authentication....
    Describe what happens to the text in the box above when each of the following keyboard keys are pressed(3 marks)
    1. tab
    2. enter
    3. home
  2. State four characteristics which make computers better than human beings.(4 marks)
  3. Give three reasons why primary storage devices are not used for secondary storage.(3 marks)
  4. Asha has a hardware shop and lately, she is finding the task of managing daily sales in the shop overwhelming. (a)
    1. State a retail system that she should acquire.(1 mark)
    2. State two input devices that are used in retail systems.(1 mark)
    3. Apart from enhancing the speed of operation, state two other benefits that Asha will gain from using such a system.(2 marks)
  5. The accounts department of a secondary school is using a system that generates invoices that are printed in triplicate using carbon papers.
    1. Name one type of printer suitable for this task.(1 mark)
    2. Give a reason for your answer in (a) above (1 marks)
  6. A secretary saved a document in a computer. After some time, she could not remember the name and the location of the file. State four file details that are assigned a file by the operating system which can assist in tracing the file.(2 marks)
  7. A student tried opening an application program on a computer that was functioning well. The program did not load and the operating system reported that the memory was insufficient. Give two causes of such response.(2 marks)
  8. State two measures that can be put in place to control piracy of software.(2 marks)
  9. Identify three hardware considerations to be made before installing an operating system.(3 marks)
  10. A water company sends out clerks to read water meters. The data collected by the clerks is then fed into the computer and then all the bills are printed at the same time.
    1. State two advantages of this approach.(2 marks)
    2. Name this type of data processing.(1 mark)
  11. A school has acquired a system that imitates human teachers. Students can learn by getting answers from the system which they would normally get from the teacher. Give three advantages of this system.(3 marks)
  12. Pesa Mingi company has offices in Nairobi and Kampala connected in a network. The management is convinced that someone is illegally gaining access to the data in theircomputers. State three ways in which the company can overcome this problem. (3 marks)
  13. State the purpose of each of the following in database design.
    1. input mask(1 mark)
    2. default value(1 inark)
  14. State the importance of considering the following factors when acquiring a software.
    1. warranty;(1 mark)
    2. portability.(1 mark)
  15. State two appliation areas of real time systems.(2 marks)

SECTION B (60 marks)
Answer question 16 and any other three questions from this section in the spaces provided.

    1. Give two characteristics of scripting languages.(2 marks)
    2. Describe two types of errors that may be detected during program testing. (4 marks)
    3. A company's workers travel to work either by public or by private means. All workers are paid a travel allowance of Ksh. 200, but those using private means are paid an additional Ksh. 100.
      1. Write a pseudocode to determine a worker's travel allowance.(3 marks)
      2. Draw a flowchart to determine a worker's travel allowance.(4 marks)
      3. Other than occupying large space, state two disadvantages of using a flowchartinstead of a pseudocode.(2 marks)
    1. State three standard data coding schemes used in computing and electronic systems.(3 marks)
    2. Convert each of the following numbers: 
      1. 110.1012 to decimal;(3 marks)
      2. 12.687510 to binary;(4 marks)
    3. Subtract 110.012 from 11001.01012.(2 marks)
    4. Using twos complement, perform the following binary arithmetic leaving the answer in binary notation.
      1101- 1001012  (3 marks)
    1. What is meant by each of the following terms as used in table creation?(1 mark)
      1. cell margin;(1 mark)
      2. nested table. (1 mark)
    2. State four types of text wrap that can be applied to a graphic.(2 marks)
    3. Distinguish between each of the following:
      1. axis labels and data labels;(2 marks)
      2. cropping and sizing. (2 marks)
    4. Figure 1 shows a section of a worksheet containing information on household items. Use it to answer the questions that follow.
        A B C D E
      1 Item Description No of Units Cost per Unit Total Cost  
      2 Wheat flour   12  110    
      3 Rice  6  145    
      4 Sugar 7  140    
      5 Salt 2  20    

      1. Write a formula to calculate the total cost of rice.(1 mark)
      2. The prices of all items increased by 10% and the value 10% is placed in cell B8. Using cell addresses with absolute referencing only, write a formula to calculate the new unit price of salt.(2 marks)
      3. Write a function to display the number of cells in which the cost per unit is equal to 110.(2 marks)
      4. Write a function to display the least total cost for all items. (2 marks)
    1. What is meant by each of the following terms as used in the internet?
      1. surf:(1 mark)
      2. uploading:(1 mark)
      3. inbox.(1 mark)
    2. A school has set up its network using wireless technology to link computers. State three problems that the school is likely to experience when using this technology.(3 marks)
    3. List three ways by which parents can protect their children from accessing inappropriate content from the internet,(3 marks)
    4. Explain three problems associated with using e-mail technology for communication.(6 marks)
    1. Explain three reasons why an organization may need to change to a new computerised system.(6 marks)
    2. State why each of the following is important in system documentation.
      1. sample data;(1 mark)
      2. output reports.(1 mark)
    3. Name the tools used for data storage in each of the following methods of data processing.
      1. manual;(1 mark)
      2. electronic.(1 mark)
    4. A teacher manages students' records by storing daily attendance information in a file called register and students' personal records such as year of birth and home address in a file called students.
      1. Identify the types of computer files named above.(2 marks)
      2. Give a characteristic of data held in each file.(2 marks) 
      3. Name the field that should be used to link the two files.(1 mark)


    1. Tab: Moves the text ahead to the next tab stop or several stops ahead/ right/ forward.
    2. Enter: Break the line after the word 'is' so that the word 'an' starts on a new line.
      Words from "an" forms a new paragraph.
    3. Home: Takes the cursor to the beginning of the line.
      Nothing happens to the text
      (3 marks)
    • Computers can be automated or programmed
    • Computers are fast.
    • Computers are capable of performing repetitive tasks.
    • Computers can store a lot of information.
    • Computers are accurate.
    • Can do dangerous tasks.
    • Give quality output.
    • Diligence /don't get tired/sick.
      (4 marks)
    • They are more expensive
    • They hold less volume of data
    • They are volatile hence cannot store information once power is off.
    • Its shorter access time is dependent on the memory size hence increasing the size of primary memory will eventually lead to longer access time.
    • ROM cannot store data
      (3 marks)
    1. Point of sale system (POS)/Data base management system/stock control system/ sales management system. 
    2. Keyboard, barcode scanner, credit card reader.
      • Transactions will be accurate.
      • Automatic updating of transactions.
      • Automatic updating of stock level.
      • Provide daily and periodical summaries for management use.
      • Improved security/limited access.
      • Easy of storage of files.
        (4 marks)
    1. Impact printer/Dot matrix/Daisy wheel.
    2. It prints by using spokes which hit the paper hard.
      The energy is transferred to attached carbon papers.
      (2 marks)
  6. File properties:
    • File types.
    • File extension.
    • File size.
    • Creating time/date of storage/saves time,
    • Owner/Account used.
    • Time of modification/date.
    • Usage conditions/File attributes (Read Only/Archives/Hidden).
    • Protection information.
    • Contents of the file - Access time.
      (2 marks)
    • System infected with viruses which occupy memory space.
    • Many utilities are running in the background (e.g antivirus).
    • Many applications are opened.
    • RAM may be smaller than the required/part of RAM corrupted.
    • Corrupted Registry.
      (2 marks)
    • Enactment of relevant laws to compact the vice.
    • Stiff penalties for those found in possession of pirated software.
    • Sensitize the public on the harm of using pirated copies.
    • Making software affordable/cheaper.
    • Certificates to identify the original software,
    • Use of keys,passwords to secure software products.
    • Restrict the number of installations.
      (2 marks)
  9. Hardware consideration:
    • Main memory size/volume/capability.
    • Hard disk size.
    • Available input devices.
    • Available output devices.
    • Processor specification ie. speed/type/hardware.
    • Monitor resolution.
    • Bandwidth for busses (e.g 64-bit)
    • Compatibility
    • Configuration
    • Warranty terms for hardware.
    1. Advantages:
      • Shifts time of processing to when computers are less busy.
      • No user input required hence no idle computer time as it awaits input.
      • Input is done once (batch).
      • Can enable use of hired equipment hence cost effective.
        (2 marks)
    2. Batch processing.
      • Electronic.
  11. Advantages:
    • Can be used in the absence of human teachers.
    • Combines the expertise of many teachers hence more knowledgeable.
    • Reduces cost of hiring many teachers/serves many students.
    • Preservation of scarce expertise.
    • Students can learn on time.
      (3 marks)
    • Encryption.
    • Firewalls.
    • User profiles/passwords/user.
    • Limit the number of log-in attempts,
    • Audit trail/tracking.
    • Physical protection of computers.
      (3 marks)
    1. Input mask: Is a layout/format that filters the data that can be entered in a field.
    2. Default value: Used to specify the value that is automatically entered in a field when a new record is created.
    1. Warranty:
      • If a software has a problem then it can be replaced.
      • If not working can be returned for repair.
    2. Portability:
      • To ascertain the compatibility with other systems.
    • Booking and reservations. eg. hotel, car, bus, air ticket.
    • Space explorations.
    • Intensive care units (hospital). (ICU)
    • Chemical plants/nuclear
    • Military security
    • Banking eg. ATM.
      (2 marks
    1. Characteristic of scripting language:
      • Use of tags.
      • It is interpreted and not compiled.
      • Do not have declaration part,
      • User friendly
      • Are portable.
      • Must be embedded in the browser.
        (2 marks)
      • Syntax Errors: Errors arising due to violation of language rules.
      • Logical Errors: Errors arising from poor logic such as incorrect use of formulas/ semantic.
      • Runtime Errors: Occur when there is abrupt interruption of running program. When the running program stops abruptly.
        1. Input transp_means
        2. If Transp means = Public Then
          Transp_allowance = 200
          Transp_allowance = 300
        3. Print Transp allowance
        4. Exit    
        • Flowcharts require templates/complex symbols/special software while pseudo code
          requires only a text editor.
        • Drawing flowcharts takes a lot of time.
        • Flowcharts occupy more space.
        • Flowcharts permit development of logic sequences which cannot be coded using valid structured code.
        • Translation of flow charts into individual code is harder/difficulty.
      1. Binary coded Decimal (BCD) (4 bits).
      2. American Standard Code for information interchange (ASCII).
      3. Extended BCD interchange code.(EBCDIC)
      4. Unicode.
      5. Standard BCD (6 bits)
        (3 marks)
      1. 1102 = 4+2
        0.1012 = ½ + ½
        Sum = 6 + ½ + ½
        = 6 5/8 or 6.625 
      2. 12
        2 6 R 0
        2 3 R 0
        2 1 R 1
        2 0 R 1
        0.6875 x 2 = 1.375
        0.375 x 2 = 0.75
        0.75 x 2 = 1.5
        0.5 x 2 = 1.00
        1100 + 0.1011
        = 1100.10112 
    3. 11001.0101
    4. COMP (100101) = 011010 + 1
      Carry = 0
      recomplement the answer
      1. Cell margin: Its the space between the boundary of the cell and the text/ content inside the cell.
      2. Nested table: is a table created inside another table.
      1. In line with text.
      2. Square
      3. Behind text.
      4. Infront of text.
      5. Tight. - Through.
      6. Top and bottom.
      7. None.
        (2 marks) 
        • Axis label: Data corresponding to the vertical or horizontal lines of a given chart whereas ie x-axis and y-axis.
        • Data label: are data that provide additional information about a data marker which represents a single data point on a value that originates from a worksheet cell.
      2. Cropping is the process of trimming/cutting/hiding vertical or horizontal edges of an object/picture while sizing is the process of enlarging/expanding or reducing/contracting an object/ picture to appropriate dimension.
      1. = Product (B3:C3)=Product (C3,B3)
      2. = & B &8* C5 + C5 = Product (&B &* *C5)+C5
      3. = Count If (C2:05 = 110)
      4. = Min (d2:05)
    1. Surfing: Its the process of accessing /browsing/visiting internet resources like webpages.
      1. Uploading: Transferring files from a computer to a remote computer.
      2. Inbox: Folder/place in email system where incoming messages are stored/saved.
      1. Slower than a wired network.
      2. The network can be less stable, wireless reception may be impaired by other wireless and wired devices within the network.
      3. Risk of outsider accessing the network,
      4. Very difficult to configure.
      5. Very hard to secure.
      6. Very hard to trouble shoot.
        (3 marks) 
      1. Block in appropriate content/Firewall/Filter.
      2. Set limits on downloads.
      3. Monitor where children go online.
      4. Counsel children eg. not talking to strangers online,
      5. Supervise them.
      6. Giving user accounts/passwords/log ins.
        (3 marks)
      1. Threat to privacy.
      2. Organisation system admn"
      3. Can snoop into peoples mails.
      4. Email can be unsolicited/spam mail.
        Messages can be sent to masses of people without their consents.
      5. Vulnerability to machine failures.
      6. Emails can be overwhelming when many messages are received leading to email overload and going through each of them can be taxing.
      7. Email can be faked.
      8. Email attached can be a source of viruses.
      9. Email technology not available to all/Technology illiteracy.
      10. Encourage illicit communication such as immoral behaviour.
        (6 marks)
      1. Current system may be experiencing problems thereby being unable to meet organisation requirements. 
      2. New directives may be received from authorities and the organisation must comply.
      3. Changes in the operating environment forces the organisation to change in order to fit and continue in business. eg. competition.
      4. Changes in technology requiring the upgrading or total change in the existing system.
      5. Peer pressure need to remain fashion
        (6 marks)
      1. Sample data should be provided so that all modules can be tested.
      2. Output reports show that the system actually works/testing process/expected output
      1. Manual: Manual files stored in cabinets/books/paper/in-tray/out-tray.
      2. Electronic: Secondary storage devices/individual storage devices eg. Flash .
      1. Student: Master file/Parent/Reference File/Primary.
        Register: Transaction file/Child table/Secondary.
      2. Master file: Data is static/Permanent/Semi-permanent.
        Transaction file: Data is dynamic/Temporary/Changes frequently
      3. Key field: Student number/Admission No./Reg. No./File No.
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