Computers

Computers

1. Systems Architecture

   • CPU - Made up of 3 main components
     • control unit
       • The component of the CPU that manages instructions.
     • Arithmetic and logic unit
       • A component of the CPU that performs arithmetic and logic calculations
     • Immediate access store
       • Holds the data needed straightaway by the control unit.
     • CPU Speed
       • Clock speed
         • speed at which the CPU can carry out instructions is called the clock speed. This is controlled by a clock.
           • CPU fetches and executes one instruction. The clock speed is measured in cycles per second, and one cycle per second is known as 1 hertz.
             • The higher the clock speed a CPU has, the faster it can process instructions.
       • Cores
         • A dual core processor can fetch and execute two instructions in the same time
       • Cache
         • most common used instructions and data are stored in the cache
   • Von Neumann Architecture
     • John von Neumann invented the processor architecture which stores a program in memory
       • processing architecture that all CPUs use.
       • processor has five special registers which it uses for processing:
     • data and instructions are both stored as binary digits
       • data and instructions are both stored in primary memory
         • instructions are fetched from memory one at a time and in order (serially)
           • the processor decodes and executes an instruction, before cycling around to fetch the next instruction
             • the cycle continues until no more instructions are available

2. Logic Gates

   • Circuit components which take several inputs, compare the inputs with each other, and provide a single output based on logical functions
     • input
       • Data which is inserted into a system for processing and/or storage.
     • Output
       • Data which is sent out of a system.
   • NOT
   • OR
   • AND
   • Boolean
     • A data type in computing which only has two possible values, true or false.
       • binary
         • A number system that contains two symbols, 0 and 1. Also known as base 2
     • truth table
       • Used to assess possible results of a Boolean algebra statement
     • True or False

3. E-Safety

   • Staying safe online
     • Cyberbullying
       • DPA (Data Protection Act)
         • Social media
           • Safeguarding
             • Hacking
               • Use Virus protection software
               • Spyware
       • Report online bullies
     • Don't tell people your email address
     • Never give out your real details

4. Python Programming

   • A high-level programming language
   • Variables
     • Used to store Text or Numbers
     • NAME
     • TYPE
     • VALUE
     • Variables have names
     • String=Text
     • Integer=Number
     • Use quotes " " in text strings