Computing topics 1-4

Computing topics 1-4

1. Topic 3: Software

   • A program that controls, or makes use of the hardware
     • Three types, development, system and application
   • • 4 Jobs: Providing a User Interface Memory management Hardware management Handling files
   • System Utilities
     • Security
       • Antivirus
       • Spyware protection
       • Firewall
     • Disk organisation
       • Defrag
       • File Transfer
       • Formatting
   • Types:
     • Off the shelf
       • Proprietary
       • Open source
     • Bespoke

2. Topic 1: Fundamentals of computing

   • What is a computer system
     • An integrated collection of electronic or mechanical parts which work together for a common purpose
   • Man-Made Systems
     • A system which is made by man
     • E.G. The Railway, Computers, The Canal Network, Traffic light network
   • What is a system
     • It must take in something, do something with it and then output it
   • What does a computer system include?
     • An Input Device
     • An Output device
     • A Processor
     • A Storage Device
   • Testing
     • Alpha: Company Only
     • Beta: Certain members of the public
     • Sets out to purposely break the system
     • Tested against two key areas:
       • To identify any weaknesses in the system in meeting specification
       • To identify coding Errors
   • Standards
     • De Facto
       • Common Usage
       • E.G. HTML
     • Proprietary
       • Owned by 1 company
       • E.G. Windows
     • Industry
       • Agreed across the industry
       • E.G. The USB
     • Open
       • Publicly available
       • E.G. The World Wide Web
   • Issues
     • Ethical
       • Ethics refer to what we think is morally wrong or right
       • Some are laid down by the British Computing Society (BCS)
     • Legal
       • Designated by law
       • Data Protection Act
         • 8 Principles
           • 1: Data must be fairly and lawfuly collected
           • 2: Personal Data can only be held for specified, lawful purposes
           • 3: Personal Data should be adequate and relevant
           • 4: Personal Data should be accurate and up-to-date
           • 5: Personal data should not be kept any longer than necessary
           • 6: Data must be processed in accordance to the subject's rights
           • 7: Appropriate security measures MUST be taken
           • 8: Personal Data cannot be transferred out of the EU unless it has similar legislation
       • Computer Misuse act
         • Against illegal access to computers
     • Environmental
       • Computer insides contain poisonous metals
       • Virtual servers: Lots can be stored on a single physical one
       • Steps for recycling: 1: Ask self if you can upgrade current version. 2: Ask if company or council have recycling scheme. 3: If neither has one, give to charity. 4: Permanently delete personal data

3. Topic 4: Representation of Data

   • Binary to denary
     • TABLE!!
       • Headings: 128, 64, 32, 16, 8, 4, 2, 1
   • Denary to Binary
     • TABLE!
       • If heading goes into it or remainder, put a one underneath then takeaway heading
   • Hexadecimal
     • 0-9, normal, 10-15 A-F
   • Character sets
     • Each letter given value in binary

4. Topic 2: Hardware

   • Input, Output and Input/Output devices
     • Input Take input, convert it into binary
       • E.G. Keyboard, Mouse etc.
     • Output: Takes processed binary and presents it
       • E.G. Screen
     • Input/Output
   • Secondary Storage
     • Primary Storage = ROM(Uneditable) or RAM(Volatile)
     • Stores files
     • E.G. CD, Tape, Solid State
   • The CPU
     • 3 Parts
       • ALU
       • CU
       • Registers
     • AKA the Processor
     • Fetches code, decodes it then executes it
     • Testing process is called benchmarking
     • Factors affecting performance are:
       • Type(CISC or RISC)
       • Clock speed(Processes per second)
       • Cache Size
       • Cores
         • The three parts per core
   • Motherboard and Buses
     • Motherboard: A circuit board on which the CPU sits
     • Bus: A circuit on the motherboard that connects the CPU to something
   • Binary Logic
     • Binary: A number system of 1s and 0s
     • 3 main gates
       • AND
         • If both numbers=1, gate=1
       • NOT
         • Turns 1 to 0 etc.
       • OR
         • If ANY numbers =1, gate=1
   • ROM/RAM
     • ROM: Permanent Storage of BIOS
       • Non-Editable
     • RAM: Temporary storage for modules and code for running programs
       • Volatile
   • Virtual Memory
     • When RAM is full, a protion of the hard drive is reserved for the same task