GCSE ICT/GCP Revision Guide
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Section One- What is A Computer?
editData
editData has NO MEANING
- Data is information that has no meaning.
- Data only becomes information when you know the context of the data.
- Information = Data + Meaning
Data is stored in Bytes
- Computers use a binary code (i.e. they use only 2 digits) to represent data. Usually, a circuit that's switched on represents the digit 1, and a circuit that's switched off represents the digit 0.
- Bit: Each individual 1 or 0 is called a bit - short for binary digit.
- Byte: 8 bits is called a byte.
- Kilobyte: 1 kilobyte (1 KB, or simply 1 K) is about a thousand bytes. to be exact, 1KB = 2 to the power of 10 = 1024 bytes.
- Megabyte: 1 megabyte (1MB) is about a million bytes. To be exact, 1 KB = 2 to the power of 20 = 1048576 bytes.
Computer System
editData is entered at the input stage
- information is converted into data before its entered into the computer
The computer then processes the data
- Processing involves turning the input data into something else
The results are then sown at the output stage
- Output is when the computer communicates the results of the data processing to the user.
- The two most common ways are a screen display and printed paper.
- At this point the data becomes information again
- The information obtained at the output stage might then be used as feedback to input more data. this turns the system into a cycle.
Computerised v. Manual Systems
editTypes of Computer
editNetworks - LANs and WANs
editNetworks - Different Configurations
editNetwork Security
editRevison Summary
editSection Two- The Parts of A computer System
edit9-Input Devices
editAn input device is any hardware which is used to enter data into the computer system. The input devices of a computer are
- QWERTY Keyboard
- Mouse
- Camera
- CD
- Microphone
- Scanner
- Disk Drive
- Joystick
12-The CPU
editCPU stands for Central Processing Unit
- The CPU is the portion of a computer system that carries out the instructions of a computer programs
Section Three- Using a A computer System
editSection Four- System Analysis
editSection Five- Text and Image Processing Software
editSection Six- Spreadsheets and Database
editThe Basics
editSpreadsheets are clever calculators
edit- A spreadsheet is a program that can display and process data in a structured way.
- Spreadsheets can process numbers and also handle text.
- spreadsheets can be used to:record data, search for particular items of data, perform calculations based on data, produce graphs and charts.
Data is entered into cells
edit- Spreadsheets are formed by tables- rows and columns divide them selves in to cells.
- Each cell can be recognized by using coordinates by using the row number and column letter.
Each cells can contain one of three things
editCells can only contain one thing of these three things
- Numerical Data- for example numbers, money and dates
- Text Data
- Formulas
Creating and improving
editSimple Formulas
editThe Trickier stuff
editGraphs and Charts
editSection Seven- Measurement, Control and simulation
editSection Eight- The Internet
editInternet Basic
edit- The Internet is an International Network of computers
To connect you need Special Hardware and Software:
- Most people access the internet using a PC connected to a telephone cable or cable TV services these two items can not work without a modem. A modem converts data from the computer into a format suitable for sending over the telephone or other communication line. Both ends of the connection need a modem.
- The Internet Has Two Main Parts:
1) The World Wide Web (WWW) is the part that contains web pages. 2) Electronic Mail(E-MAIL) is the part where messages are sent from one person to another - it works a bit like sending a letter.
- There is 5 step to sending an E-mail
Step 1-Create the message Step 2-Connect to the Internet Step 3-Press the send button Step 4-The message is sent from the sender's ISP to a mailbox in the computer system of the recipient's ISP Step 5-The recipient later connects to the internet, opens their e-mail account, and finds the new message
- Emails has Benfits and Problems
Emails take quick to send It is cheaper than posting or faxing The same message can easily be sent to loads of diffent people Both need Internet access and Email accounts
Using the World Wide Web-Navigating
edit- The Internet is a huge Source of Information
You can access the Internet form any computer, the Information is up to date.
- Type in the URL
URL stands for Uniform Resource Locator URLS's can not cantain capital letters or spaces or certain types of punctuation
Navigating and Downloading
editWeb Page Design
editUsing the Internet-Data Security
editUser-Generated Content
editSocial Networking
editOnline Audio and Vedio
editOnline Software
editRevision Summary
editSection Nine- Computers in the real world
editComputers in Shops
editComputers in Banks
editSection Ten- Computers and Society
editParvin+Eisha
Computers And The Law
editComputer are used to store and process important data. As it is easy to transfer data through the internet. So there are laws to protect the use of computers
The Copyright, Design and Patents Act Controls Illegal copy
editThis law was introduced in 1989, this law made it so that it was illegal to copy a file without permission from the owner, or copyright user.
Three ways that this law is broken up into:
- Using software without a proper licence. E.g. if you acquire a MS software disk and upload it onto one computer station, it is illegal to use it on any other computer station.
- Downloading text or images without saying where you have gotten it from, or with receiving the copyright owner's permission.
- Copying a computer program that you use at another place and running at a computer at home without the permission from the copyright holder.
The computer misuse act prevents illegal Access to files
editThis law was introduced in 1990 to stop hackers and viruses. The act made the following three things illegal:
- Unauthorised access to computer material. E.g. hacking
- Attainment of unauthorised access to a computer to carry out serious offence such as fraud and blackmail.
- Unauthorised changing of computer files. E.g. planting viruses and deleting files