Computing

Computing

1. Binary Logic

   • Data is represented as binary logic because it is simple for the computer to understand as it only contains two sates 1 = ON 0 = OFF
     • Binary numbers are stored in the system at different voltage levels
     • The electronic circuits in computers can be wired together to form logical calculations
     • These circuits are based on logic gates - AND, NOT and OR

2. CPU

   • CPU's have multiple processing units, each one is called a core
     • Each core can run multiple programs at the same time
     • Some cores are faster than other's but better cores are often expensive
   • Clock speed is the measurmenet of cycles per second
     • Clock speed determines the overall performance of the CPU
       • The faster the clockspeed the faster the computer runs
   • The CPU processes data
     • It uses a three step system - FETCH,DECODE and EXECUTE
     • Cahce is a form of short term memory
       • It can be quickly acessed by the CPU and often holds frequently used important instructions
       • The more cache the CPU has the better it's overall performance

3. Memory

   • ROM stands for Read Only Memory
     • ROM is Non-Volatile meaning it doesnt delete it's self when the system is shut off
     • It stores frequently used instructions for when the computer boots up
     • Often mounted on the mother board
   • RAM stands for Random access memory
     • Volatile memory meaning it deletes it's self when the system powers down
     • It temporarily stores programs and data that are being used at any given time
     • Allows users to multi-task when switching between different windows
     • The more RAM a user has the more programs they can have open at any one time
     • Flash memory is where the hard disk is used to temporarily store some of the RAM contents
   • Advances in technology offer more RAM,Cache,Rom,Secondary storage capacity etc at a higher access speed allowing systems to store more and run faster

4. Secondary storage

   • Magnetic hard drives use metal platters coated in a magnetic material and a series of read/write heads
     • This allows data to be accessed by read heads as the disk spins up to 7000 rpm
     • New data can be added to the hard disk via the write head
     • Hard drives are often contained internally and have to be taken out
     • Hard drives have a large storage capacity but slow access speed compared to other secondary storage
   • Optical storage is where data is burned on the surface of a disk using laser beam
     • One data has been burned on it cannot be re-written
     • Optical storage is very portable
     • Optical storage disks have a low capicty
   • Solid-State devices such as flash cards use a series of logic gates
     • They are very portable
     • Data can be read/written unlike optical storage
     • They can be easily removed - often inserted in a USB port

5. INPUT/OUTPUT devices

   • INPUT DEVICEs
     • MOUSE
     • KEYBOARD
     • MICROPHONE
     • JOYSTICKS
     • GAMING CONTROLLERS
     • WEBCAMS
     • REMOTE CONTROLS
     • SCANNERS
   • OUTPUT DEVICES
     • PRINTER
     • PLOTTER
     • SPEAKER
     • HEADPHONES
     • MONITOR
     • VIRTUAL REALITY HEADSETS
   • INPUT?OUTPUT DEVICES
     • VOICE_ACTIVATED SYSTEMS
     • EYE TRACKING
     • MULTI-TOUCH GESTURES
     • FINGER PRINT RECOGNITION