Keywords Summary For AS Level

Chapter – 1

Data, Information, Knowledge and Processing

 Difference between Data, Information and Knowledge

• Data – Raw facts 

• Information – Data items that give context and meaning

• Knowledge – Understanding of what information is about (here)

 Sources of DATA (here)

o Static Data

 Data that never change

o Dynamic Data

 That updates as a result of a change in the source

o Direct (Primary Source) (here)

 Collected directly by the user and used only for the intended usage of the data

o Indirect (Secondary Source) (here)

 Already existing data used for another purpose.

 Coding of Data

o Process of representing data by assigning a code to it for classification or identification

 Need to encode data (here)

o Computers understand only binary digits hence analog information has to be coded

 Encryption (here)

o Scrambled data

o Cipher Text

 Methods of Encryption

o Symmetric Encryption

 Both sender and recipient possess the encryption key

o Asymmetric Encryption

 Public key – By all senders

 Private key – only by the recipient

 Encryption Protocols (here)

o SSL – Secured Socket Layer 

o TLS – Transport Layer Security

 Validation and Range of methods (here)

o Presence Check

o Range Check

o Type Check

o Length Check

o Format Check

o Lookup Check

o Consistency Check

o Check Digit

 Verification and Range of Methods

o Visual Verification

o Double Data Entry

 Proof Reading (here)

o Process of checking the information 

Codecs (here)

            For encoding and decoding audio and video files 

Chapter – 2

Hardware and Software

Hardware Devices – physical components of a computer system

 Motherboard

          Printed Circuit Board that connects the main components

 Random Access Memory RAM (here)

o to store currently active programs and data

o Volatile in nature

 Read Only Memory ROM –

o Permanent and non-Volatile

o Used for booting process

 Graphics Card

• Display the output image onto the monitor

 Hard Disk Drive (HDD) (here)

•  Common form of secondary storage device
• Uses platter for storing device

 Solid State Drive (SSD) (here) 

• Uses static parts
• Stores in flash memory

 Cloud (here)

• Data stored on banks of servers
• Accessible anytime with the help of Internet

 Optical Character Reader (OCR) (here)

Picture analyzed and character recognized

 

 Magnetic Ink character Recognition

Reads the MICR code from a cheque

 Operating System- OS (here)

o Controls and Manages the hardware

 Device Drivers (here)

o To connect the devices to the computer

 Utilities

o Software that do core programs

• Anti-Virus (here) & (here)
•  Backup (here)
• Data Compression(here)
•  Disc Fragmentation(here)
• Formatting(here)
•  File Copying 

 Compiler (here)

o Converts a high level language to machine language

 Interpreter

o Translate a program line by line

 Linker

o Combines object files together 

o Word Processing (here)

• To process words

o Spreadsheet (here) & (here)

• To perform calculations and modeling

o Database Management System (DBMS) (here) (here)

• To manage and manipulate data

o Graphics manipulation Software

• To work on an image

o Photo Editing Software

• Focused on editing the photographs

Web Authoring Software(here)

 Used for creation and editing website

Custom-written software(here)

Tailored made for an organization

o Off-the-shelf software

General purpose software available to large market

Conference

o Audio

o Video (here)

o Web

Chapter – 5

Digital Divide

Digital Divide (here) (here)

Chapter – 6

Using Networks

Networking computers

o Client – Connected to a server (here)

o Server – Caters to the client requests

o Peer – another machine on the network(here)

o LAN – Local to a building (here)

o WAN – Connection of different LANs spanning huge area (here)

o VPN – Virtual Private Network (here) (here) (here)

o Intranet – Confined to an organization (here)

o Extranet – Access to the partnering companies of the organization (here)

o Internet – Interconnection of different networks (here) (here) (here) (here) (here) (here)

o The world wide web – Global Network around the world (here)