CPU

HARDWARE

A CPU, is the brain of the computer system, it stands for Computer, Proccesing, Unit.

It works by looking up what to do with the input, for example you press print, CPU, collects the information needed to do it in the  ROM (Read Only Memory) and then stores that temporarily in the RAM (Random access memory) while it is waiting to process it. It then does what it tells it to do, for example prints the paper.

It is super fast at doing this. This is the endless cycle of fetch, decode and excecute. Fetch the information, turn it into binary code, and do the action/output.

Cache memory is often inside the CPU, it is used to store instructions that are used to repeatedly run programs, it is extremely fast and used to speed up the process.

Binary Logic

Binary is just 0's and 1's,  they can be used to represent all numbers.
it is used because they can be represented easily using an on/off state or switch.
computers use logic gates to manipulate the data.

AND GATE
only 1 if there are two 1's

this table shows the inputs and what the output would be

OR GATE
only 0 when there are two 0's

NOT GATE
output is opposite to input

This is what happens when you combine and  then not

ROM, FLASH, VIRTUAL AND CACHE MEMORY

Input and output

We need input and output devices because to make something happen, you need to be able to give it info on what to do, and it needs to then do something.

Possible input devices could be your body, via 3d sensers, our brains. Outputs can be almost anything, like a picture, video, movement, ordering something online.

Input and output devices, can help people with specific needs a lot.  For example we can communicate with Stephen hawking using eye sensers, in the past, their would be no real way of communicating with him.

If you are paralysed, in the future, they could hook you up to a brain sensor and you could communicate that way.

Order stuff online, even be hooked up to some sort of machine, that you could walk around using, and pick stuff up.

Secondary storage

Stores information when the power is off.

There are 3 main types, optical, magnetic and solid state.

We need it because otherwise we would have to upload data every time we turn it on, but using secondary data, the data will stay as it doesn't dissapear over time.

Magnetic storage

Reliable, lots of storage at a low cost, can be internal or external.

Hard drive, normally in the computer itself, most of them have one.

Optical storage

Lots of storage at low costs, small and easy to distribute, they are robust and are normally read only,

Includes CD's and DVD's.

http://www.amazon.co.uk/TDK-CD-R80CBA10-B-CD-R-80min-Spindle/dp/B000A33TD2/ref=sr_1_2?ie=UTF8&qid=1382346135&sr=8-2&keywords=blank+cds

10cds with 700mb each for under £3 or equivalent of 30p each

Solid state

Includes stuff like USB, can be more expensive than other storages, flash memory, fast access times.

Include USB's or memory sticks.

This one costs £20 with 16GB memory space.

http://www.amazon.co.uk/Kingston-Technology-16GB-DataTraveler-DT101G2/dp/B003MWJKVI/ref=sr_1_1?ie=UTF8&qid=1382346591&sr=8-1&keywords=USB