COMPUTER PLATFORMS

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COMPUTER PLATFORMS
Input, Output, and Storage Introduction to
Basic Computer Architecture Week 2
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Week 2

• Input, Output, Storage
• Devices
• Media
• Computer Architecture
• The CPU
• ALU
• Control unit
• Registers
• Buses
• Von-Neumann

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Input

• Sending information to the computer
• Issuing the computer with a command
• Devices for Input
• Keyboard
• Mouse
• Scanner
• Camera
• Joystick / Gamepad
• Microphone (Transducer)
• Lightpen
• Barcode Reader
• Fingerprint Scanner

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Output

• Returning the result of a process
• Querying the user
• Providing the user with feedback
• Devices for Output
• Monitor
• Printer
• Plotter
• Digital Projector
• Speakers
• Synthesiser
• Robot / Machine
• LEDs

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Storage

• Place to keep important data
• Kept on a storage medium
• Magnetic, Optical, physical
• Devices for Storage
• Hard Disk Drive (HDD)
• Floppy Disk Drive (FDD)
• Zip Drive
• Tape Drive
• CD / DVD (ROM, RW, R)
• Memory Chips (USB sticks, Flash memory)
• Punched Cards
• Barcodes

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Computer Architecture

• Whats in the box?

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Ports

• Physical interface or socket to connect a device
  to a computer
• Interfaced to the computers motherboard
• Two main types of port
• Serial
• Data is transferred in streams
• One bit after the other
• Parallel
• Data bits are transferred alongside each other in
  waves (concurrently)
• Common ports
• USB (Universal Serial Bus)
• Serial (9-pin) (15-pin game port)
• Parallel (25-pin)
• SCSI (Small Computer Systems Interface)

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Sound Graphic Cards

• Interface directly onto the motherboard
• Graphics Card usually uses the AGP (Accelerated
  Graphics Port)
• Provides basic and / or advanced graphics
  capability
• Often have graphics co-processors
• On-board VRAM (Video RAM)
• Sound card uses a PCI (peripheral Component
  Interconnect) slot
• Allows computer to output sound to speakers and
  record sounds.
• Adds MIDI (Musical Instrument Digital Interface)
  capability

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Hard Disk Drives (HDD)

• Magnetic storage medium
• Uses rotating metal disks (platters)
• Use read and write heads to store and retrieve
  information
• Large storage capacity

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Floppy Disk Drive (FDD)

• Magnetic storage medium
• Uses rotating single, thin magnetic disk
• Requires a drive to read the disk, which has the
  read/write heads
• Small storage capacity
• Typically 1.44 Mb (High Density 3.5)
• Portable
• Cheap

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Magnetic Disks

• How the disk works

Cluster
Sector
Track
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BIOS

• Basic Input Output System (BIOS)
• Provides the computer with basic functionality
• Built-in software, no disk access
• Usually a ROM chip on the motherboard
• Common BIOS manufacturers
• Award, Compaq, HP
• Settings are saved to a CMOS chip, powered by a
  battery
• CMOS Complementary Metal Oxide Semiconductor

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Random Access Memory (RAM)

• Used to store instructions that are in current
  use
• Two main types of RAM
• Static RAM (SRAM)
• reliable
• does not need to be constantly refreshed
• fast
• expensive
• Dynamic RAM (DRAM)
• more common
• slower than SRAM
• cheap
• must be constantly refreshed
• Both volatile (contents lost when power is off)

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Random Access Memory (RAM)

• Cache Memory
• Essentially RAM that the CPU can access quickly
• Is physically close to the processor
• Usually always SRAM
• Therefore, small sizes are common compared to
  size of RAM
• Two levels of cache memory
• Level 1 - Situated inside the processor
• Commonly 512 kb
• Level 2 - A separate RAM chip on the motherboard
  or in expansion slot
• Commonly 1024 kb (1 Mb)

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Central Processing Unit (CPU)

• CPU has three important parts
• ALU (Arithmetic and Logic Unit)
• Control Unit
• Registers

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Central Processing Unit (CPU)

• Arithmetic Logic Unit
• Handles mathematical and logical functions
  (numerical)
• Deals with non-numerical logic operations
• Control Unit
• Handles all low-level hardware operations
• Input Output Devices and CPU
• Carries out instruction handling
• Fetch Execute Cycle
• Registers
• Storage areas within the CPU
• Accessible at high speed
• Anything for processing must be kept in a
  register
• Can also hold the address of a memory location

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Buses

• A collection of wires which connects together the
  internal components of the computer
• Allows transfer of data
• Main types of bus
• Data bus
• Carries actual data bits (information)
• Address bus
• Transfers locations where data should be sent
• Control bus
• Carries status information

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Buses

• How buses fit into the computer system

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Computer Architecture

• The Von Neumann Model
• 1903 - 1957
• Mathematician
• Quantum physicist
• Worked on ENIAC
• Electronic Numerical Integrator and Computer
• Major development in computer technology
• Responsible for developing the Fetch Execute
  Cycle, and his namesake -
• Von Neumann Model
• The original computer geek?!

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Week 2

• What we know now!
• Input, Output, Storage
• Devices
• Media
• HDD
• FDD
• How magnetic Disks work
• Computer Architecture
• BIOS
• Ports
• The CPU
• ALU
• Control unit
• Registers
• Buses
• Von-Neumann