meaning of different memories

BIT: a bit is short for binary digit and is the smallest data in a computer. a bit has a single binary value, either 0 or 1.

Mb: MB is short for megabit, this is mainly used for download speed.

MB: MB, meg or mbit is a common measurement used with computer storage media, a

megabyte is equal to 1,048,576 bytes.

KB: KB short for kilobytes are most often used for small sized files.

GB: A GB is short for gigabyte and is a measure of computer data storage capacity and is roughly a billion bytes.

TB: Terabytes are most often used to measure the storage capacity of large storage devices.

Bytes: The byte is a unit of digital information in computing and telecommunications that most commonly consists of eight bits.

1 bit (a 0 or 1 binary digit)

A bit is the smallest amount that a computer can store (using ON or OFF in a circuit).

1 nibble = 4 bits

1 byte = 8 bits (an ASCII character takes 1 byte.)

So 1 byte = 2 nibbles!

1 kilobyte = 1024 bytes

1 megabyte = 1024 kilobytes           (or 1024 x 1024 bytes)

1 gigabyte = 1024 megabytes           (or 1024 x 1024 kilobytes)

1 terabyte = 1024 gigabytes

exam questions

The traffic lights in town are controlled by a computer system.The towns council os concerned about the reliability of the system. 

Explain, using examples from the  traffic light system, what is meant by reliability and why the town needs the system to be reliable.

Reliability is when something has to be trusted e.g. if a institution installed a new computer system they would have to regularly check if its reliable otherwise it could crash and peoples work   could get lost,

 This is the same way the traffic light computer system works  but instead the affect it would have would be more severe because if people were driving and all of a sudden the traffic light computer system crashed and the traffic lights stop working people could get in to accidents to prevent this they should check the computer system regularly and do regular test on computer systems warn and people that it is likely for the computer system to crash and they should be careful and be aware of the traffic lights in case  they stop working.

legislation

Ethical and environmental considerations

Explain what is meant by E-waste?
 WEEE encourage consumers to recycle unwanted electrical items known as E-waste.

Discuss the environmental issues that arise when they are disposed of in landfill sites?
the environmental issues that arise when used electronics are disposed of in landfill sites is that people live there and have farms the only reason why countries do this is because that area or country is too poor to do anything about it.

professional standards

1.Explain what professional standards are, why professional standards are necessary 
and the problems that arise if there are no standards.

professional standards are needed to share data and hardware peripherals across the world so everybody can use the same data if there were no professional standards no one would be able to connect with each other.

2.Name a standards organisation responsible for setting industry-wide standards

Defecto
Propietry
USB-universal serial bus is used to transfer data between devices.
Bluetooth-allows us to connect with wireless devices, but only from short distances.
Not all standards are hardware some could be software.

b) Give examples of standards these organisations are responsible for.



What is meant by ‘propriety standards’?



What is a ‘de facto’ standard?
a de facto standard is one created almost by default because of one dominant player in that industry.

What are ‘open standards’?
A open standard is the specification for hardware or software that are developed by a standards organization.

http://www.cambridgegcsecomputing.org/fundamentals-of-computer-systems-main#top

reliability of computer systems

Reliability is crucial and unreliable systems can cause disaster.
Name one example of a computer system in the airline, medical or banking industries
and explain why it needs to be reliable. 

The reliability of computers is important because if a bank decided to install a new computer system without checking it multiple times it is likely it could crash or freeze this could cause a lot of problems e.g  people wouldn't be able to access their bank accounts to make a payment or withdraw money from cash machines it could get the company in trouble or if the airline installed a new computer system and it froze while the plane was flying with passengers on the plane the airplane would crash and everyone on the plane will die.

Give examples of two different measures that can be taken to improve the reliability of
computer systems. 

One way company's could prevent this is by having regular check ups to see if there are any problems another way to prevent this is by warning people what they are doing so people know there might be technical difficulties and they should expect it.

Glossary

Computer system-a serious of input that is processed by a computer

Hardware-the computer itself

Software-operating information used by a computer

Input- things put into the computer (keyboard, mouse, memory stick, sensors and bar code readers.

Output-things that come out of the computer (monitors, headphones, speakers and printer projectors.

Process-   processing is the stage where the input data is manipulated in order to produce meaningful information.

Storage- storage for work to be saved into the computer (hard disks)

Elements of the CPU

-the CPU consists of 3 major components

-the Arithmetic and logic unit (ALU)

-The memory unit

-The control unit (CU)

The ALU- does mathematical tasks rapidly performs calculations and logic operations from 1/10

(ON/OFF) data from the memory unit. The ALU transforms the digital data and outputs the resulting value

The memory unit

 Consists of a small number of memory registers which will store items of data and send them to the ALU for processing. The results of the processing will be copied back to the memory unit for storage.

The CU is in charge of processing it interprets the software instruction and sends the right data and operation to the ALU. It accepts the results of the processing from the ALU.