stuart cunningham - computer platforms - 2003 computer platforms input, output, and storage &...
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Stuart Cunningham - Computer Platforms - 2003
COMPUTER PLATFORMS
Input, Output, and Storage
&
Introduction to Basic Computer Architecture
Week 2
Stuart Cunningham - Computer Platforms - 2003
Week 2• Input, Output, Storage
– Devices– Media
• Computer Architecture– The CPU
• ALU• Control unit• Registers
– Buses– Von-Neumann
Stuart Cunningham - Computer Platforms - 2003
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
Stuart Cunningham - Computer Platforms - 2003
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• LED’s
Stuart Cunningham - Computer Platforms - 2003
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
Stuart Cunningham - Computer Platforms - 2003
Computer Architecture• What’s in the box?
CPU
Hard Disk Drive
RAMBIOS
Sound Card
Graphic Card
Ports
Floppy Disk Drive
Power Supply
Stuart Cunningham - Computer Platforms - 2003
Ports• Physical interface or socket to connect a
device to a computer• Interfaced to the computer’s 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)
Stuart Cunningham - Computer Platforms - 2003
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
Stuart Cunningham - Computer Platforms - 2003
Hard Disk Drives (HDD)• Magnetic storage medium
• Uses rotating metal disks (platters)
• Use read and write ‘heads’ to store and retrieve information
• Large storage capacityDisk Platter
SpindleRead/Write Heads
Stuart Cunningham - Computer Platforms - 2003
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
Stuart Cunningham - Computer Platforms - 2003
Magnetic Disks– How the disk works:
Sector
Cluster
Track
Stuart Cunningham - Computer Platforms - 2003
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
Stuart Cunningham - Computer Platforms - 2003
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)
Stuart Cunningham - Computer Platforms - 2003
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)
Stuart Cunningham - Computer Platforms - 2003
Stuart Cunningham - Computer Platforms - 2003
Central Processing Unit (CPU)• CPU has three important parts:
– ALU (Arithmetic and Logic Unit)– Control Unit– Registers
High Speed Registers
ALU Control Unit
CPU
Stuart Cunningham - Computer Platforms - 2003
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
Stuart Cunningham - Computer Platforms - 2003
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
Stuart Cunningham - Computer Platforms - 2003
Buses• How buses fit into the computer
system
INPUT OUTPUTCPU
MEMORY
ADDRESS BUS
DATA BUS
CONTROL BUS
Stuart Cunningham - Computer Platforms - 2003
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?!
Stuart Cunningham - Computer Platforms - 2003
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