Hardware

Hardware

1. Input and Output Devices

   • An input device is a piece of hardware used to put information into the computer
   • An output device is a piece of hardware used to take information out of the computer
   • Some pieces of hardware are input devices and output devices like:
     • Fax machine
     • Touchscreen
     • Headset microphone
   • Supermarket checkouts use input and output devices to do their basic functions these include:
     • Printer to print receipts
     • Touchscreen for inputing and displaying information
     • Scanner to scan the barcode
   • Specific needs
     • Some people are not able to use a computer so they use special input and output devices to help them some of these include:
       • Foot mouse
         • A mouse operated with your foot for if you have little or no arm movement
       • Braille keyboard
         • Customised keyboard that has braille as well as letters and numbers
       • Eye typer
         • Uses sensors to calculate where you are looking and it will position the mouse there.Can click by slowly blinking

2. Secondary storage

   • Secondary storage is where the computer stores all of its information
   • A computer needs secondary storage as without it you would not be able to run any programs
   • Internal
     • Internal storage is what is stored on the hard drive
   • External
     • External storage is where you store things outside of the computer itself like on a memory stick
   • Different variations of secondary storage include:
     • Magnetic hard disk
       • Internal
       • Moving parts break easily
       • Reliable
     • Tape storage
       • Large capacity
       • Serial access
       • External
     • Optical disk
       • Cheap
       • External
       • Fragile

3. The CPU

   • The CPU's sole purpose is to process data it does this using the fetch-exeute cycle
     • The fetch-execute cycle is where the CPU retrieves an instruction and carries it out
   • The Control Unit
     • The control unit is part of the CPU that directs the proccesses to where they need to go
   • The ALU
     • The arithmetic logic unit is where the CPU performs its operations
   • Registers
     • Register are a small amount of storage that is used to store the information the CPU is currently working with
   • Cache
     • Cache is a component that stores data so future requests for that data can be served faster
   • Clock speed
     • Clock speed is the amount of time it takes to procces each piece of data and is often measured in megahertz (MHz)
     • Clock speed can be sped up by by overclocking.Overclocking is the process of forcing a computer or hardware component to operate faster than its original clock speed

4. Binary logic

   • • AND gate
       • A B P 0 0 0 0 1 0 1 0 0 1 1 1
     • NOT gate
       • A P 0 1 1 0
     • OR gate
       • A B P 0 0 0 0 1 1 1 0 1 1 1 1

5. Memory

   • Latency
     • latency is how much time it takes for some data to get from one point of the computer to another
   • ROM and RAM
     • RAM
       • Random access memory is where the computer stores information so that it is closer to the CPU
       • The more RAM the computer has the better its performance as transporting the information takes time and slows down the computer
     • ROM
       • 'Read only memory' contains the boot up program for the computer
       • Different types of ROM
         • ROM - Read Only Memory, PROM - Programmable Read Only Memory, EPROM - Erasable Programmable Read Only Memory, EEPROM - Electrically Erasable Programmable Read Only Memory, Flash EEPROM memory
     • Their characteristics
       • RAM
         • Volatile
         • Can be modified
         • Runs applications
       • ROM
         • Non-volatile
         • Can not be modified
         • Runs boot up functions

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