• URL is clicked/typed into a web browser address bar. The page is requested (by the web browser) so HTML and files are fetched from a web server and the browser collates the page, which is then displayed on the monitor.
• OR
  URL is clicked/typed into a web browser address bar (1). The browser locates the IP address either in cache or using a DNS server and the browser sends a request to the web server with that IP address web server uses HTTP to send back the requested web page and the browser displays the content of the page .

• Labels
• Values
• Formula
• Functions

• A denial of service strategy usually works flooding the target host or network with traffic until the target can’t respond or crashes. The targeted systems operations are affected when users are unable to access information systems and or network services

Input : An algorithm can take 0 or more inputs well defined outputs

Finiteness: an algorithm must terminate in finite time and after finite number of steps. 

Definiteness : an algorithm must be clear and unambiguous. Each and every step of an algorithm must be clear and precise and it must have only one meaning

Feasibility: should be feasible with the available resources

Output : must produce at least one well defined output

Independent : should have a step-by-step directions which is independent of any programming language

Correctness: should solve the problem it is designed to solve

Efficiency: must take the shortest time possible to run and should require the least memory space. It should use a minimum number of computation steps and memory to produce the desired  output. takes little time and memory to run

Generality: should not be limited to a specific case. It should work for all the valid inputs. works for many possible inputs

Effectiveness : should statements that are relevant to the problem. Every step must be basic and essential. 

Advantages

• Sharing of software and data files
• Sharing of hardware, e.g. printers
• Communication

Disadvantages

• Security of files is more of a problem

• virtual memory

(i) Jobs collected together for processing at a later time
(ii) Output produced quickly enough to affect the next input
(iii) User has direct contact with the processor
(iv) User cannot communicate directly with the processor

• Bus topology is characterised by common transmission media shared by all the connected nodes
• Star topology is characterised by a central switching node connected directly to each of the multiple nodes in the network

Advantages of Star topology over Bus topology

• Faster communication as compared to bus topology
• Independent line of connection allows freedom of removing or adding nodes

Disadvantages of Star topology over Bus topology

• Expensive as compared to the bus topology
• Long cable length

Router

• Repeaters : amplify data signal thereby extending the physical coverage of a network. It can connect two LANs locally.
• Bridges: connect similar types of networks e.g a token ring to another token ring
• Routers: link networks of different types
• Gateway: allows computers in a network to connect regardless of their topology

input

• from sensors
• from camera images [Max 2]

processing

• analyse data from sensors
• calculate average traffic flow/speed
• send signals to adjust change lights/timing

output

• change lights at the junction
• change timing plan

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

• Network operating systems
• Protocols

c) Distinguish between a source program and a compiler as used in computer programming. [2]

Source program is the original program in a high level language as written by the programmer while a compiler is a program translator that converts source program to object code.

MAR( memory address register)

• Stores the address/location where data will be read/written/accessed/fetched
• stores address/location of data/instruction being processed
• stores address/location of data/instruction next to be processed

MDR or  memory data register

• Stores the data/instruction that is fetched/read from memory
• stores the data that is to be written to memory
• stores the data/instruction from the address in the MAR
• stores data/instruction next to be processed

 Program counter

• Stores the address/location of the next instruction to be run
• stores the address/location of the current instruction being run

Accumulator

• Stores the result of manipulation/process/calculation

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

• Reads the data/packet to find the recipient's address 
• Has physical connections to >=2 different networks
• Holds a routing table
• Stores information about (IP) addresses 
• Keeps packets inside a network by not forwarding them 
• Forwards data / directs/forwards/sends packets 
• Chooses the most efficient path to the next node

1. SECTION A
2.  Answer all questions in this section
3. What is a computer?                                                                                                            1mks
4. State three physical components that make up a computer                                                 3mks
5. State the hardware technological differences between the second generation and third generation computers                                                                                                          2mks
6. State and explain three characteristics of a computer                                                         3mks
7. State the functions of the following special memories in a computer                                3mks
8. Buffers
9.  
10. Registers
11. Cache
12.  
13. Define the following as used in data representation in a computer                                  (5mks)
14. Bit
15.  
16.  
17. Byte
18.  
19.  
20. Nibble
21.  
22.  
23.  
24. Word
25.  
26.  
27.  
28. Word-length
29.  
30.  
31. State two reasons why a DVD is superior to a typical compact disk                               (2mks)
32. State three advantages of flat panel monitors over cathode ray tube monitors                   3mks
33. Explain the following terms as used in word processing                                                  3mks
34. Section breaks
35. Thesaurus
36. Superscript
37. State two advantages of  impact printers                                                                             2mks
38. State the function of the following keys on the computer keyboard                                  3mks
39. Enter key
40. Insert key
41. Delete key
42. State the technology used by the following secondary devices to store data                      3mks
43. Magnetic storage devices
44. Solid state storage devices
45. Optical storage devices
46. State three reasons why an operating system is important in a computer                         3mks
47. A typical computer’s main memory consists of both volatile and non-volatile memory.
48. i)  Explain what is meant by the term volatile memory                                          (1mark)
49. ii) What is normally stored in the non-volatile part of a computer’s main memory (1mark)
50. Explain why having cache memory can improve the performance of the CPU         (2mks)
51. What is a computer system?                                                                                           (1mk
52. Give two differences between a solid state drive (SSD) and a hard disk drive (HDD)   2mks
53. State three categories of software classified according User license agreement              (3mks)
54. State two disadvantages of Random Access Memory                                                       (1mk)
55.  
56.  
57. a) Explain the functions performed by the following components of a processor   (2 marks)
58. Control unit

• It refers to a computer that controls other computers in a network and monitors user's access to the shared resources.

• Overtype mode: deletes the current text at the cursor position and replaces the existing characters with new text
• Insert Mode: pushes the existing text away as new text is inserted between the existing text