Hardware

Hardware

1. Motherboard

   • Cpu
     • Central Processing Unit
     • Arithmetic Logic Unit: processes and manipulates data - It performs simple calculations - it is also able to perform comparisons on data which allows programs to make a choice – e.g. in a high-level language, an IF statement.
     • Control Unit: It ensures that all processes take place at the right time and in the correct order.
     • FDE
       • Step 1: The processor checks the program counter to see which instruction to run next.
         • Step 2: The program counter gives an address value in the memory of where the next instruction is.
           • Step 3: The processor fetches the instruction value from this memory location.
             • Step 4: Once the instruction has been fetched, it needs to be decoded and executed. For example, this could involve taking one value, putting it into the ALU, then taking a different value from a register and adding the two together.
               • Step 5: Once this is complete, the processor goes back to the program counter to find the next instruction.
                 • Step 6: This cycle is repeated until the program ends.
     • Registers: storage location found on the CPU where data or control information is temporarily stored. They are usually much faster to access than internal memory, since they have to be accessed so often. An accumulator is a common example of a register. This is the register used by the ALU to store the results of its calculations
     • Internal Memory: sometimes called level 1 cache memory - is fast access temporary storage on the CPU. Data is moved from the registers to the internal memory when it is not being used. Data from the internal memory can then either be written to RAM or called back into the registers for further processing.

2. Storage

   • Secondary Storage
     • Optical storage uses technology such as lasers. Laser beams are projected onto a CD/DVD or Blu-ray disk and if light is reflected back, then data is read as a 1 and if light is not reflected back, data is read as a 0. Lasers are used to read and write information to a disk
     • Solid State
       • Media such as USB flash memory sticks.  It is called solid state as it does not have any moving parts, such as a read-head in magnetic storage.  Solid state storage is increasingly used to replace both magnetic and optical storage, especially in mobile devices, where its low power consumption and high speed access is advantegeous

3. Embedded Systems

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