• Guided media uses cables to connect to computers whereas unguided media uses waves.

• their small wavelength allows conveniently sized antennas to direct them in narrow beams, which can be pointed directly at the receiving antenna

• It prevents double-booking which could happen in paper-based booking system
• The customer gets immediate feedback on the availability of seats
• The customer can make  booking at any time of the day
• Emails provided by customers during booking can be used by companies for advertisement

• Used to resize the image
• Used to rotate the image
• Used to move the image

A backup is a copy of data that can be used if the original data is lost.

(a) Linear/Cascade/Waterfall

• a project is divided into stages or phases
• it is sequential, each stage needs to be completed before moving on
• clear goals are set for each stage

(b) Iterative Methodology

• effective in producing a working prototype in a short period of time
•  involves extensive user input and testing
• based on build – test – evaluate process, the philosophy is re-build until users are completely satisfied
• features user input throughout the process which enables ongoing, responsive changes to be made to the design.

• Refers to the scrambling of data into unreadable form before transmission over a telecommunication media  OR
• transformation of data from plaintext to ciphertext

1. Availability in the market
2. Initial and maintenance cost
3. User friendliness
4. Compatibility
5. User needs

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

• Easy to add nodes
• Managed centrally
• Fewer data collisions
• A single node failure does not affect the rest of the network

(a) Cookies

• Information that a website stores about a user on their hard disk; this enables
  the website to remember details about the user when they next visit the website.

(b) Spyware

• Program installed on a PC to gather information about the user. It monitors
  every key press and relays the information back to the home base

(c) Phishing

• Sending an email that claims to be from a legitimate company; the recipient is then directed to a bogus website where their personal details will be collected

(d)Spam

• Junk/ (unsolicited) electronic mail advertising products and services sent to a general mailing list.

(e) Pharming

• Malicious code installed on a PC or on a server. This code directs users to a
  a fraudulent website without their knowledge.

• 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

• it has a header that contains the destination address, the packet number, and the originator’s address
• it has a payload
• it has a trailer.

Advantages

• on-line catalogues can be viewed
• much larger choice of products
• product reviews obtainable before purchase
• orders placed over internet any time day or night
• download software purchased straight away
• good and services usually cheaper on the internet
• programs that can search for best price/cheapest
• very fast placing an order has been placed as customer name, address
• and credit card details are stored so no need to re enter
• buy goods from anywhere in the world
• no need to go to shop/save travelling time

Disadvantages

• spam
• need a credit card to shop on-line/not everyone has a credit card
• hackers could retrieve credit card numbers and use them to buy goods
• security fears - of giving credit card number over the internet/fraud
• goods must be delivered/can not have the goods immediately
• can not touch/handle/see the goods

1. Hardware failure
2. Corrupted software files
3. Hacking into the system
4. Power failure

• not able to directly manipulate the hardware
• may need to wait for translation before running
• the program may be less efficient.

• Installing the latest versions of antivirus software
• Avoiding downloads from untrusted sites
• Scanning removable storage media for viruses before use
• Scanning attachments for viruses before opening or downloading

• a computer that responds to requests to provide information and services over the Internet - an Internet server
• defines how messages are transmitted and formatted over the Internet-HTTP
• software that enables users to access/view documents and other resources on the Internet - Browser     
• numerical ID for each device on the Internet-IP address
• unique ID for a network interface card  -MAC address

• A HDD can contain multiple platters (disks);
• A disk/disks that move/spin
• Each platter is divided into sectors;
• The disks are spun at a very high speed (approximately 7,200 rpm to 10,000 + rpm);
• Read\write heads (move across the disk to) read and write data;
• There is one read\write head for each side of a platter ie two heads per platter;
• Data is written to\read from the disk by magnetising\polarising\sensing microscopic regions on the disk;
• Data is organised in concentric rings called tracks;
• There is a small circuit board on the drive that controls the reading and writing of data;
• Data is transferred from and to the disk via a cable/electrical current being passed;
• The intersection of sectors and tracks are called blocks;
• Data is read 1 block at a time

Shielded twisted pair cable:
A twisted pair cable is made up of four pairs of twisted copper wires, a shielded twisted pair cable applies a shield to each one of the pairs on a cable or to all of the pairs together. This shield can reduce EMI (electromagnetic interference), which would be emitted from heavy machinery. This increased data transmission quality in the workshop. STP can also reduce crosstalk.