Revision notes:

c.p.u
A central processing unit (CPU) also referred to as a central processor unit is the hardware within a computer that carries out the instructions of a computer program by performing the basic arithmetical, logical, and input/output operations of the system.

Cores
A multi-core processor is a single computing component with two or more independent actual central processing units (called "cores"), which are the units that read and execute program instructions. The instructions are ordinary CPU instructions such as add, move data, and branch, but the multiple cores can run multiple instructions at the same time, increasing overall speed for programs amenable to parallel computing. Manufacturers typically integrate the cores onto a single integrated circuit die (known as a chip multiprocessor or CMP), or onto multiple dies in a single chip package

L.A.N
LAN Advantages:
• Workstations can share peripheral devices like printers. This is cheaper than buying a printer for every workstation.
• Workstations do not necessarily need their own hard disk or CD-ROM drives which make them cheaper to buy than stand-alone PCs.
• User can save their work centrally on the network’s file server. This means that they can retrieve their work from any workstation on the network.
• They don’t need to go back to the same workstation all the time.
• Users can communicate with each other and transfer data between workstations very easily.
• One copy of each application package such as a word processor, spread sheet etc. can be loaded onto the file and shared by all users.
• When a new version comes out, it only has to be loaded onto the server instead of onto every workstation.

LAN Disadvantages:
• Special security measures are needed to stop users from using programs and data that they should not have access to;
• Networks are difficult to set up and need to be maintained by skilled technicians.
• If the file server develops a serious fault, all the users are affected, rather than just one user in the case of a stand-alone machine

Networks
A computer network or data network is a telecommunications network that allows computers to exchange data. In computer networks, networked computing devices pass data to each other along data connections. The connections (network links) between nodes are established using either cable media or wireless media. The best-known computer network is the Internet

Hardware needed to connect to the internet

If you already have a PC with keyboard, mouse, etc. and an operating system installed (such as Microsoft Windows) it will depend on whether you are using: dial-up you will need a modem which connects from your computer to the telephone line or, broadband you will need either: a USB broadband modem which connects your computer to the telephone line, or: an ADSL Modem/Router which plugs into your telephone line and (depending on which kind of ADSL Modem/Router you get) some way of