Understand Computer Hardware

Understand Computer Hardware

1. Computer Components

   • Processors
     • CPU - Central Processing Unit
       • Manages all the hardware
         • Input-Process-Output Cycle
         • Storage Devices
           • Internal
           • External
           • Records locations for future retrieval
       • Initially single core
         • 1 instruction at a time
         • Multicore
           • Multi-instruction
       • Components
         • Control Unit
           • Instructions received and undertaken in correct order
             • Input/Storage Devices
               • Temp Store: Registers
         • ALU
           • Mathematical/logical operations
             • Complete instruction
             • And
             • Or
             • Not
           • Data --> Accumulator
   • Motherboards
     • Main printed circuit of a PC
       • Other components such as the CPU connected via sockets
       • Printed circuits from data highway
         • Data can be stored where needed and retrieved when required
       • Specific to each CPU - not interchangable
   • Storage
     • Registers
       • Small and fast
       • Chiefly used by the CPU
         • Stores...
           • ALU processed data
           • Instructions on what to do with the data after processing
           • Operating System Data
             • Oversees basic tasks
     • SAS
       • Most widely used storage protocol
       • Serial Attached SCSI
         • Follows same protocol as SCSI
           • Transmits data serially
             • 3.3 gigabits of data sec-1
             • 128 devices
   • Ports
     • Location where a communication channel enters/leaves a system
       • Point at which a device is plugged in
         • Usually has an interface
           • Interface converts data to correct format
       • Each port has a number
         • Easy to ID and select peripherals
         • Ports can be identified by their external shape
     • USB
       • Universal Serial Bus
         • Standard for digital data comms
           • SHORT distances
           • Covers..
             • Cables
             • Connectors
             • Protocol
       • Connect with standalone devices
         • Printers
         • Camcorders
         • Cameras
         • MODEMs
         • Mobile devices
     • Firewire
       • Similar to USB architecture
         • Conforms to IEEE 1394 standard
           • Don't need to be linked via computer
           • P2P
       • High speed transfer of a lot of data
         • Media devices to computers
     • Network Ports
       • Physical ports that connect computers to...
         • MODEMs
         • Routers
         • LANs
     • Ethernet Ports
       • Cable based networks
         • Linked directly to network card
     • Serial Advanced Technology Attachment
       • SATA
         • Hard Drives
           • Computer
         • Linked to motherboard
           • 7-pin ribbon cable
   • Memory
     • RAM
     • ROM
     • Cache
   • Expansion Cards
     • Printed circuit boards
       • Smaller than the motherboard
       • Connector allows them to be plugged into motherboard
   • Power Supplies
     • PSU
       • AC from mains
         • Converted to DC
       • Require cooling system
         • PCs
           • Fans
         • Larger
           • Water coolant system
     • Backup Generator

2. Types of Computer System

   • Embedded
     • Computers in other things (eg fridges or cars)
     • Internet of Things
       • Global network of connected objects
         • Not limited to traditional computers
           • Anything with a RFID chip
             • Radio Frequency ID
             • Constantly getting smaller and cheaper
               • Increasing connectivity
   • Mainframe
     • HUGE
       • Designed to solve scientific and engineering problems
         • Performs complex calcs/manipulation, collection and storage of lots of data
     • Reliable and secure
       • Rigorous backups
       • Component redundancy
         • If a component fails another will take its place
           • IPO cycle not interrupted
     • Expensive
     • Require teams of experts to oversee use
       • Process large amounts of data quickly
         • Banks
         • CC companies
   • Quantum
     • Experimental
     • Use qubits
       • Not limited to 2 states
       • Represent atomic particles
         • Several states at the same time
     • Many million times quicker

3. Connectivity Methods

   • Wired
     • Copper
       • Twisted Pair
         • Often used in telephone systems
         • Pair of insulated wires are twisted together
           • Several twisted pairs = twisted cable
         • Shielded
           • Combine shielding and cancellation
             • Metallic jackets
       • Coaxial
         • Copper cores surrounded by...
           • Dielectric insulators
           • Woven copper shielding
           • Outer plastic sheath
         • Can be used near other metal
     • Fibre
       • Fastest WIRED
       • Thinner = better signal
       • Travels at speed of light
         • Unidirectional
           • At least two must be placed in a cable
   • Wireless
     • Bluetooth
       • Short range communications
         • 2 devices
         • Network hub not required
         • Within 10m
     • Infrared
       • Must be in line of sight AND only few m apart
         • Works well over short distances
       • Infrared LED received by photodiode in receiver
         • TV remote control
       • Relatively cheap
     • Microwave
       • Analogue or digital
       • Short RW via microwave towers
       • Must be in line of sight
         • No obstructions between microwave antennae
     • Laser
       • 10km range
         • Compromised by fog/haze
           • Droplets refract light
       • Can send large quantities of data
         • Devices must be in line of sight
         • Used in satellite to satellite communication
     • GSM
     • 3G/4G
     • Wi-Fi
       • Connects devices via network hub
       • Up to 94m depending on freq.
         • Compromised by obstructions
           • More than 1 network access point may be required

4. Communications Hardware

   • Switch
     • Receives packets and forwards them to specified device
   • Router
     • Forwards packets between networks
     • Must be linked to at least 2 networks
   • Hub
     • Central connection point for all devices on a network
       • All devices have equal call on resources
         • Receive copies of all packets
   • MODEM
     • Modulator Demodulator
     • Converts between analogue and digital signals
       • Data transmitted along telephone lines.
   • HYBRID
     • Combination of all
     • Generally suited for personal use
       • Can't meet commercial specs
   • Wireless Access Point (WAP)
     • Allows networks to connect to a wireless one
     • Router can be a WAP but WAP cannot be a router