Units of storage:

8 bits = 1 byte
1024 bytes = 1 Kilobyte
1024 Kilobytes = 1 Megabyte
1024 Megabytes = 1 Gigabyte
1024 Gigabytes – 1 Terabyte
1024 Terabytes = 1 Petabyte

Translation of high-level program code to binary (machine code):

• interpreters – translates source code to machine code line by line, spots errors more easily but takes longer.
• compilers – translates the source code to machine code in one step, does not spot errors as line being typed, but more efficient. Creates a run time version (object code) that can’t be edited.

Use of binary to represent and store:

• Real numbers uses mantissa & exponent – 0.256 X 10⁵
  Mantissa = 256 Exponent = 5
• Characters – ASCII allocates a different binary code to each letter, A = 00100001
• Instructions, machine code – Binary instructions the processor can understand 10101011101
• Graphics bit-mapped and vector
  • Bit-mapped graphics are made up of pixels
  • Vector graphics are described in text <rect width=”300″ height=”100″ style=”fill:rgb(0,0,255);stroke-width:3;stroke:rgb(0,0,0)”>

Basic computer architecture:

• Processor (CU Ah Luv U Right)
  • Registers – temporary storage locations holding data being processed
  • ALU – deals with comparisons and arithmetic calculations
  • control unit – controls all other parts of the processor, ensures instructions are carried out in the correct order
• Memory
  • Random Access Memory – temporary data storage only held as long as the computer is switched on.
  • Read only memory – Permanent memory not lost when the computer is switched off, can’t be changed.
• Buses
  • data – carries data to and from the processor, memory and other devices. Bi-directional
  • address – carries address info from processor to the memory.
  • control – made up of a number of separate wires.
• Interfaces
  • allows a processor to send and receive data to and from peripherals like printers, scanners, keyboards and projectors.
  • Bluetooth – Wireless
  • USB – Wired