i) To manage the execution of instructions
By running a clock
To decode instructions
(ii) To store OS
To store those parts of applications programs currently running
To store data currently in use
(iii) Part of the processor where data is processed/manipulated
All I/O must pass through here

(The parent can) set criteria for the websites she is allowed to visit such as a whitelist/blacklist of websites. The firewall will examine the data/traffic incoming and outgoing from her computer. If data is sent from a website that is not allowed, it will be blocked

- Passwords
- Hierarchy
- Only allow some staff to access student files
- Only some machines able to access
- Physical location of these machines
- Physical lock on machines
- Encrypted data in files
- Firewall if connected to the Internet

(a) Phishing

• Phishing is a strategy that encourages a computer user to part with sensitive information such as bank details hence the term ‘phishing’ – i.e. fishing – trying to catch someone out. For example, a perpetrator sends a user an email that appears to be genuine, for example, pretending to be a bank or a lawyer requesting that the user verify bank account details or send money to assist in the completing of a legal case.

(b) DoS

• DoS is a means of attack on a specific user/system/website which involves overloading a target with too much network traffic resulting in system slowdown, shutdown or a violation of security.

download speed :
– speed at which information/data is transferred FROM server/Internet
– speed at which information/data is transferred TO the user’s computer
upload speed :
– speed at which information/data is transferred FROM user’s computer
– speed at which information/data is transferred TO the Internet/server

• Binary can represent two states because computer circuits use transistors, which can either be on or off

• A compiled program will only execute on a processor of specific type/family/with same instruction set
• A program run using an interpreter can execute on a computer with any type of processor;

• The different factors that can influence the performance of a network include: bandwidth, network design, data collisions, and excess broadcast traffic.
• The bandwidth can influence through the method of transmission and medium used

• The number of FDE cycles run per given time/second
• the frequency that the clock ‘ticks’
• 3.8 billion cycles/instructions per second

Phased:
Advantages:

• only a small part of the operation affected if new system fails
•  no need to pay for two sets of wages

Disadvantages:

•  time consuming (each part needs testing fully before expanding system)

Pilot:
Advantages:

• if new system fails, only that part will be affected
• possible to gradually train staff on pilot before whole system changes over

Disadvantages:

•  time consuming (waiting to see how pilot works before rolling out to rest of the organisation)

Direct:
Advantages:

•  less likely to malfunction since fully tested
• immediate benefits/less time wasted
•  reduced costs (only one system so no need to duplicate staff)

Disadvantages:

• disastrous if the new systems does fail

Parallel:
Advantages:

•  if new system goes down, there is a backup system in place
• possible to gradually train staff/staff have time to get used to the new system

• It sends control signals that manage the transfer of data and instructions within the CPU
• It decodes an instruction using an instruction set

A computer system refers to computer components that collectively function as a single unit to achieve the desired goal. It can also be defined as a collection of hardware, software, and liveware that work together to receive, process, and manage data

• To detect and remove errors
• To confirm if the program produces the expected output

Network Failure - when the network becomes faulty or the network is down, users may not access network resources hence operations of an organization may be brought to a standstill

Security Issues:  A computer network can be accessed thus there is an increased chance of hacking

The rapid spread of viruses: Viruses can easily spread to terminals of a computer network which may be very expensive to clear

Cultural and moral effects: adult content may be shared in a networked environment which may be of negative impact on teenagers

• virtual memory

• The OS allocates CPU time to each process, and prioritises them in the order of importance

• allowing the network to share resources like files and software for printers and computers
• support the network's implementation of security features
• controls user accounts
• supplies network administrators with network monitoring tools.

SECTION A (40 MARKS)

Answer all the questions in this section

1.Computer systems are built from three types of physical components: processors,memories and 1/O devices.

  a) State two tasks of a processor                                                            (2 mks)

  b)State function of 1/O devices                                                               (1 mk)

2. Threats to the safety of computer systems take many forms such as:  white-collar crime, natural disasters, vandalism and carelessness.Give on way as to how each of these forms of threats can be controlled.    2 mks)

3.a) Explain the term nibbles as used in data representation in computers

   b)Perform the following binary arithmetic giving the answers in decimal notation.     (3 mks)

       i)1110.01111 + 11010001 .011

        ii) 1001011.011 - 111.111

     4  a)  Distinguish between machine and assembly language           (2mks)

         b) State the type of translator necessary for a program written in:         (2mks)

            i) High level language

           ii)Assembly language                                                    

5. Briefly explain the purpose of the following types of program documentation: (3mks)

    a)  User manual

     b) Reference guide

     c) Quick reference guide

6. State any two features of a user-friendly program.      (2mks)

7 a) Distinguish between labels and formulae with respect to spreadsheets (2mks)

   b) Consider the entries in the cells below.

State the value displayed in cell C13                                      (2 mks)

8.List three differences between wide area Networks (WAN) and Local Area Networks (LAN)      (3mks)

9. Study the flowchart segment below and state the last value printed from the flowchart.         (2 mks)

10.  a) What is an expert system                                                        (1mk)

      b)State any two components of an expert system                     (2mks)

11. give two reasons why optical disks are better storage media compared to floppy diskettes  (2mks)

12.What are the Dos commands used for the following?                       (2mks)

            a) Changing directories

            b) Viewing directories

           c)  Renaming directories

            d) Deleting a directory

13. Distinguish between copying and moving text                                  (2mks)

14. a) Name two methods of paper orientation                                (1mk)

     b)Name two keys used to delete text in a document   (1 mk)

15.Name two features a Database package                                             (2mks)

SECTION B (60 MKS)

Answer question and any other three questions from this section

16.       Study the flowchart below and answer the questions that follow.

 a)Write a high-level language program for the above flowchart (7mks)

 b)List the outputs of the flowchart above                                 (5 mks)

 c) Modify the flowchart so that it adds up all its outputs and displays the sum obtained  (3mks)

17. A computer specification has the following details:

•  Pentium II
• 1.44 MB floppy disk drive
• 20 GB hard disk
• Full multimedia
• 17” SVGA monitor
• Pre-installed operating system
• Pre-installed office suite

     a)  What is meant by

       i)  1.44 MB floppy disk drive?

       ii)20 GB hard disk?

      iii) 17” SVGA monitor

     b) Which operating system might be pre-installed in this computer and why?         (2mks)

     c) List three multimedia components                                          (3 mks)

      d) i)  what is meant by computer aided manufacture?        (2 mks)

          ii)  Give two examples of computer aided design software.       (2mks)

18. a)Give three examples of network software                                          (3mks)

     b)List any three items that may be referred to as data terminal equipment in a network     (3 mks)

     c)Briefly explain the following terms as used in networking   (4mks)

      i) Remote communication

      ii)Distributed processing

      d) State three advantages and two disadvantages of mesh network topology. (5mks)

19. a)  a company has decided to computerize their operations.  They have decided to purchase package instead of developing their own programs.  Give three advantages and two disadvantages of this approach. 5mks)

      b) i) explain why a value such as 611233444555 may be displayed as ######### When typed in a cell of a spreadsheet (2mks)

       ii)  How can the problem in b (i) above be corrected?      (2mks)

      c) With reasons, briefly describe the most appropriate type of printer output device for the output of:  (6mks)

      i) Customer invoices on multi-part stationery

     ii) Letters to customers

     iii)Detailed engineering designs

20. a)  Distinguish between the following pair of terms                                (6mks)

      i) Data verification and data validation

      ii)Data encryption and passwords

• ICT provides graphic design tools that allow marketers to create visual content for ads , websites and even social media
• computers enable marketers to produce video content crucial for modern digital marketing using video editing tools 
• Computers are used to distribute and analyze online survey polls  that help in understanding customer preferences
• Social media platforms offer ad placement based on user demographics and interest
• Online marketing
• Social media marketing
• Target marketing
• Email marketing
• Blogging

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