PHS CyberSchool

Computer Studies SG Grade 12 - 2004

Last updated 17 Jun 2004

Theory examination May 2004 - Answers

Section A - 20 marks

Question 1 - Multiple-choice questions 

Select one answer to each question.

1. 4
2. 2
3. 2
4. 3
5. 3
6. 3
7. 4
8. 3
9. 3
10. 3

/10/ 

Question 2 - Matching columns - 1 each - 10 marks

1. Jeff Bezos
2. Sergey Brin and Larry Page
3. Carly Fiorina
4. Steve Jobs
5. Christopher Sholes
6. Steve Jobs
7. Bill Gates
8. Steve Jobs, Douglas Englebart
9. Linus Torvalds
10. Ken Kutaragi

/10/

Section B - 80 marks

Question 3 - Software - 40 marks

1. GUI, dialogue boxes, icons (1) 
2. folders, directories.defrag (2)
3.  
   1. GUI stands for Graphical User Interface, WIMP stands for Windows, Icons, Mouse and Pointers. (2)
   2. GUI and WIMP tell us what communication format the user will use to interact with the operating system. (1)
4. What is the difference between application and system software? Give an example of each. (4)
5. a set of programs (1), that monitors and controls al hardware and software activities within a computer system and acts as the user's interface with the computer (1)   (2) 
6. (4)
   1. input/output management 
   2. user interface 
   3. memory management 
   4. process management, resource allocation, time allocation
7.  
   1. Thrashing occurs when you have too many processes happening at once and the computer cannot cope. The disk drive light keeps flickering but the computer has stopped responding. It occurs when operating systems that use virtual memory spend most of their time moving data in and out of virtual memory rather than actually executing programs. (1)
   2. To stop it temporarily you need to close one or more applications.
      To prevent it on a more permanent basis you may need to consider installing more RAM. (2)
8. FAT holds information of each cluster, root directory holds information of each file including the number of the cluster that the file starts in.              (4)
9.  
   1.  
      • Macro virus - A series of instruction that automate tasks within certain applications or systems.
      • Boot sector virus - Infects the original boot sector of a floppy disk.
      • Companion virus - A viral program that does not actually attach to another program, but which uses a similar name and the rules of program precedence to associate itself with the regular program.
      • Overwriting virus - A virus that overwrites infected files, overwrites files with garbage data, effectively destroying the data overwritten.
      • Multipartite virus - Virus that infects master boot records, boot sector and files.
      • Worm - A virus that usually replicates using computer networks, such as via email or IRC.
      • Email virus
      • Trojan horse - Not technically a virus. (2)
   2. Use anti-virus package, right protect disks, disable the CMOS (1)
   3. Use Internet anti-virus package, use a firewall, use an ISP which scans mail (1)
   4. Install an aniti virus software package.    (1)
10. Drivers:
    1. acts as a translator between the device and the programs that use that device (1)
    2. PC manufacturer (1)
    3. BIOS, operating system (1)
11. Processing:
    1. In order to play music, download a file and type a word document all at the same time you need all of the tasks in memory at the same time. This is accomplished by giving each program / task a ‘slice’ of the memory for a certain length of time. (The time will be ‘rotated’ between the three tasks). To the user, however, it appears that the system is only working on one task at a time. (2)
    2. Technically this is known as Multitasking. (1)
    3. No, not all operating systems allow this to happen. Certain, such as DOS, may only run one task at a time. As can be seen in the table of the features of modern operating systems the only one that is unable to perform multitasking is DOS. (1)
12.  
    1. This means that all users have access or not to the marks folder, in other words access is granted universally. (1)
    2. On a server-based network access to the marks file is granted according to the information the central database has for that specific user. Access is granted only once it has been cleared by this database. (1)
13. Palm OS - Palm handheld computer
    Pocket PC OS - Pocket P handheld computer
    Windows CE - web-enabled handheld computers, devices in vehicles, i.e. wireless communication devices (3)
14.  
    1. needs more secondary memory (1) 
    2. zip some files, delete some files, defrag  (1) 
15. Briefly explain what the following careers in computers involves. (5)
    1. Computer technician 
    2. Computer engineer 
    3. A person with an A+ certificate
    4. A system analyst 
    5. A person with a MOUS certificate 

Question 4 - Data communication and networks - 40 marks    

1. When a LAN uses modems, microwave, satellite radio or fibre to expand out of its building or campus, it becomes a MAN.  (2)
2. (4)
   • Rights of users: using of passwords for entry into the system, limit the users rights, restrict the hours that a user can log on.
   • Using encryption when sending confidential information across a network.
   • Using firewalls to keep network intruders out.
   • Using security gates and alarms to protect equipment.
   • Using UPS in case of power failures.
   • Making regular backups.
   • Using RAID in case of a disk crash.
   • Making sure that virus protection software is kept up to date.
3. (4)
   • Regular backups are important in case data gets stolen or there is a fire or a disk crashes.
   • If a power failure occurs, an UPS continues to supply power to the computer for a period of time allowing it to be shut down correctly.
   • Use RAID.
   • Protect against viruses
4. Provide a scenario where one would use a hub, repeater and a bridge.  Your answer must cover a real-life practical application of your own choice where such devices would be used.    (3)
5.  
   1. A digital signature.- A digital code that can be attached to an electronically transmitted message that uniquely identifies the sender. Like a written signature, the purpose of a digital signature is to guarantee that the individual sending the message really is who he or she claims to be. 
   2. A certificate authority. - A trusted third-party organization or company that issues digital certificates used to create digital signatures and public-private key pairs.
   3. A digital certificate.- An attachment to an electronic message used for security purposes. The most common use of a digital certificate is to verify that a user sending a message is who he or she claims to be, and to provide the receiver with the means to encode a reply.
6.  
   1. search via a search engine such as www.google.com for 'leather gloves". (2) 
   2. place an order via email. (2) 
   3. give credit card details or pay with blue bean, or pay into their bank account via electronic banking. (2)

    

7. COMPUSCARE is a company which is gradually increasing the usage of computers in their business. Every employee who submits a sound motivation is issued with a personal computer, peripherals and software of his or her choice for the executing of his or her duties. To date the company has installed 20 computers. Four are used for bookkeeping and six manage databases that do not differ much from one another. An integrated office suite has been installed on all the computers. 
   1. Write down four advantages that the installation of a local area network would offer this company. (4) 
   2. Name three possible network topologies that the company could choose. (3) 
   3. Name two advantages that a server-based network would offer in comparison to a peer-to-peer network. (2) 
   4. What must be installed in each existing personal computer to enable the computer to be connected to the network? (1) 
8. ABC Stores have their head office and five branches in the suburbs of Cape Town. Each branch has its own manager and administrative personnel who are fully responsible for operating the branch. Each branch must report to the head office monthly. At each branch between 3 and 10 personal computers are used to process the data. Take these facts into consideration when answering the following questions. 
   1. What kind of area network will be found at each branch? (1) 
   2. What kind of area network will link the whole group of stores? (1) 
   3. At store A all 8 workstations are individually linked with a separate cable to a central hub. What kind topology is used here? (1) 
   4. At branch B the 5 personal computers are connected without using a hub. What kind of cable can link computers without using a hub - twisted pair cable or coaxial cable? (1) 
   5. At branch C the administrative office is situated approximately 150m from the shop. What kind of additional hardware (that is the cheapest) will be needed in the line for a network which covers such a distance? (1) 
   6. At branch D the only three personal computers and a laser printer are installed in the same room. Which unguided/unbound media will be used to link the nodes? (1) 
   7. At branch E an agent visits the clients by car to make deals. Explain briefly how this agent can store the transaction data continuously on the server at the branch. Which 
      1. hardware (name two) and (2) 
      2. connection media will be needed by the agent in his vehicle? (1) 
   8. Why would the use of a dial-up line instead of a dedicated line be sufficient to connect each branch with the head office? (Read the introduction to the question.) (1) 

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