Network devices:

HUB - This is cheaper than a switch. It does not learn where each device is so it sends a message to every device connected to it so it is slower since it takes up the network bandwidth. This is an example of a broadcast device.



Switch - This device is similar to a HUB however this device learns where each device is connected to it so after each message it stores where the device is. This means that it is quicker since there is less network traffic and only the device you want to send the message to receives it. This are examples of a uni and multi cast devices.



Router - This forwards data packets between computer networks. This creates an overlay inter network. It has 2 or more data lines connecting to different networks. Routers have different types of ports (RJ45, RJ11, Serial and Wi-Fi)




A broadcast is when data is sent to all devices on the network.
A multicast is when data is sent to some, specific devices on the network.
A unicast is when data is sent to one device on a network.

Physical connections

A cable or wire
Can be touched
Limited

Logical connections

Virtual connection
Can't be touched
Multiple connections for different things simultaneously using one physical connection

DTE/DCE:
DTE - Data transmitting equipment
- Usually an end device
- Receives clock signal
- Usually "our" stuff
DCE - Data communications equipment
- Usually a comms device
- Creates clock signal
- Usually "their" stuff

Networks

A network is 2 or more devices connected to each other by exchanging data.

LAN (Local Area Network) interconnects computers in a limited area such as a household/ building using network media. The characteristic of LAN is in contrast the WAN (Wide Area Network) LAN has a smaller geographic area and non-inclusion of leased telecommunication lines.

WAN (Wide Area Network) covers a broad area such as any telecommunications network that links across regional/ national boundaries etc. This is mostly used by businesses and governments to relay data among employee’s, clients etc. From various geographical locations, the internet can be considered a WAN as well. Essentially, it is the opposite of LAN (Local Area Network). It covers a wide area whereas LAN is limited to a local area.

PAN (Personal Area Network) is a personal area you set up with your own devices, with this you can set your own hot spot up and use your I Phone, Laptop etc.

Communication barriers

Noisy environment - This will make it hard to hear the other person so people will stop communicating there and will not see each other for a while blocking communications. To prevent this you should try to meet up in quiet locations, if you can try to make the noisy environment quieter so you can hear each other properly or find alternate means of communication.

Too far away - Will make it more difficult to find a way to communicate because you will not be able to speak to each other properly or work out hand gestures so understanding meaning will be harder. To prevent this you try to meet in person regularly or find alternate means of communication such as messaging or phone them so you can talk properly.

People not listening - Can't communicate since they won't know what you are talking about and you will have to keep repeating yourself and it will get annoying so they will probably stop communicating. To prevent this you should listen to everyone and only talk to people that will listen to you. You could also find out why people aren't listening to you and try to improve on your weaknesses in conversation.

Lack of interest - people will stop listening because the other person is boring or just not interested or been talking for too long to maintain interest. To prevent this you should show interest in what people are saying and make sure you are interesting so that people will pay attention to you. You can do this by adding humor in what you are saying or change your tone of voice so it sounds more interesting.

Different language - People can't understand what the other is saying and one word might mean something different in that language so you might insult them accidentally which makes communicating very difficult. To prevent this you should talk to people that speak the same language or try to learn different languages so you can at least communicate a bit with people of other cultures.

Eye contact - No eye contact makes it difficult to know who the person is talking too so people will either lose interest or stop listening. To prevent this you should try to maintain eye contact as long as you can while talking to people but don't stare so you don't intimidate people.

Being deaf/blind - You won't know if someone is talking if you are both deaf and blind so communication is impossible. You should describe things to blind people properly and use lots of hand gestures to deaf people.

Speaking too quiet will mean other people can't hear you so they will probably stop listening, making communication difficult. To prevent this you should try to always speak loud enough for people to hear but not too loud so that people won't want to speak with you.

If you are too tired you don't try to communicate with other people so they won't bother to try to comunicate with you either so the communication will stop. To prevent this you should try to get enough sleep so that you can enthusiastically talk to people and if you are tired try not to sound moody or uninterested in what people are saying.

Cultural differences mean that in one culture a certain hand gesture might mean something good but in another culture it will mean something bad so you could accidentally insult someone and there will not be good communication. To prevent this you should try to learn differences in cultures so you don't accidentally insult people etc and if you don't know what something means don't do it.

Poor written work with spelling/grammer errors will mean that people won't understand what you have written and could think it means something else so they will write back about what they thought it was and you will be confused because it has nothing to do with anything that was previously said. To prevent this you should check what you have written and make sure everything is spelt correctly so people can read what you mean for them to read.

Processor (CPU) - brain of the computor. Speed, measured in hertz


RAM - Stands for random access memory, it is memory, size (MB, GB, TB)


Motherboard - connectivity (what hardware you can connect to it), CPU













Hard drive - size (GB, TB)












Graphics card - Size, speed (contains RAM and GPU)

Hardware

System unit

System box

For 3 main things:
1. Protection from outside harm
2. Safety - for you from electric shocks and for the system from damage from static electricity
3. Cooling - to prevent the system from overheating and burning out. This uses fans or watercooling to create air flow to cool down specific parts of the hardware




















Processor:

The CPU is more like a very powerful calculator that can calculate billions of calculations every second and because it does this so fast it does in fact look very intelligent. Everything you do on your computer is processed by the CPU.The faster the CPU is the faster it can process calculations. Every CPU does the same thing, but it is better to have a faster CPU so it can process tasks that need to be processed faster. If you use your PC for word processing, internet, email and other basic tasks you don’t need such a powerful CPU but if you are going to use your PC for gaming or graphics design you going to have a fast CPU to processes calculations.
 


RAM:

Random access memory (RAM) is the best known form of computer memory. RAM is considered "random access" because you can access any memory cell directly if you know the row and column that intersect at that cell. RAM has different slits in the top to plug in so if the slits don't match the computor you can't use that RAM



Motherboard

The motherboard is a printed circuit board that is the foundation of a computer and allows the CPU, RAM, and all other computer hardware components to function and communicate with each other. If this doesn't work then nothing will work



Hard drive

Alternatively referred to as a hard disk drive and abbreviated as HD or HDD, the hard drive is the computer's main storage media device that permanently stores all data on the computer. It consists of one or more hard drive platters inside of air sealed casing. Most computer hard drives are in an internal drive bay at the front of the computer and connect to the motherboard using either ATA, SCSI, or a SATA cable and power cable.



Graphics card

This takes the binary generated by the CPU and produces pictures from it onto your computor monitor. This allows the computor to know where put each pixel in order to show an image. This is an important part of gaming systems. If the graphics card is low capacity then the game will have poor graphics and vice versa.




Power supply unit (PSU)

This switches the current from AC (alternating current) to DC (direct current) so the motherboard isn't fried by a high ampage and to run the processor and peripheral devices































BIOS

This is a chip located in the motherboard which contains information to how your computor should operate and ensures everything is there and in working order






Peripheral devices

Camera - Takes pictures - Can connect to USB

Keyboard - Used to type - Can connect to USB, pin DIN

Mouse - Used to controll the curser so you can do things on the computor - USB

Head phones - To listen to things - USB, audio jack

Mic - To record voice etc - USB, audio jack

Joystick - To play games - USB

Monitor - To see what you are doing - VGA, S-Video, DV-I, HDMI

Speakers - To listen to things - USB, Audio jack

Printer - To print things - USB, parallel

TVscreen - To watch TV - coaxial, composite, component, DVI, HDMI


Storage

Magnetic storage -  A disc that stores data using tiny magnetised dots. These are created, read and erased using the magnetic fields created by very small electromagnets. Used for floppy dics or hard drive. For these the dots are arranged in circles on the surface of a disc with a magnetisable coating.

Solid state storage (SSD) - Used for hard drives and USB sticks. This is based on electronic storage with no moving parts. These store data using flash memory. This is a type of electronically-erasable programmable read-only memory (EEPROM)

Optical storage - For CD, DVD, BLURAY. These use patterns of tiny dots that can be read by a laser.
Operating systems:



User interface - This allows people to interact with the computor
Application management -
Hardware management - Checks all the hardware and makes sure it works
Device driver - Make the hardware do it's job
Manages resources -
File management -
Security -
Customisation - You can customise it if you don't like how it looks



Disc clean up - This will show you what files you can delete to free up space on your computor

Defrag - Computors will  fragment data, this is splitting up a file into different parts to make it fit, Defragmentation will put all these files back together to make them load faster. However this can take a long time. Whereas if you do this frequently (e.g. once a week) then it will take significantly shorter amounts of time

Formatting

Back-up - This makes a copy of all your files incase you lose your original copy so you will always have a copy

Connection types
PATA
SATA
SCSI
VSTB
eSATA
Firewire



Hypothetical scenario

Map design, old computers, throw away, update, replace. Reasons why.