CompanyCompany
LOGOLOGO
Looking Inside the Computer Looking Inside the Computer
Lecture 03: Roadmap
Parts of the Computer System Hardware Software Data User
The Information Processing Cycle Essential Computer Hardware
Processing Devices Memory Devices Input Devices
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Parts of the Computer System
Computer systems have four parts Hardware Software Data User
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Parts of the Computer System
Hardware Mechanical devices in the computer Anything that can be touched
Software Tell the computer what to do Also called a program Thousands of programs exist
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Parts of the Computer System
Data Pieces of information Computer organize and present data
Users People operating the computer Most important part Tell the computer what to do
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Information Processing Cycle
Steps followed to process data Input Processing Output Storage
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Information Processing CycleInformation Processing Cycle
Essential Computer Hardware
Computers use the same basic hardware Hardware categorized into four types Input devices Processing devices Memory devices Storage devices
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Computer HardwareComputer HardwareComputer HardwareComputer Hardware
Mother BoardMother Board
Cont.
MotherBoard also called System Board Adaopter cards, process Chips, Memory
Chips. Small chips of silicon Circuits are attached on chips. Circuits have microscopic path for current
flow. Transistors and capcitors. Transistors open and close for electricity
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Essential Computer Hardware
Input devices Allows the user to interact Input devices accept data
Keyboard, mouse
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The Keyboard
The most common input device Must be proficient with keyboard Skill is called keyboarding
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The Keyboard
How keyboard works Keyboard controller detects a key press Controller sends a code to the CPU
Code represents the key pressed Controller notifies the operating system Operating system responds Controller repeats the letter if held
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The Mouse
All modern computers have a variant Allows users to select objects
Pointer moved by the mouse
Mechanical mouse Rubber ball determines direction and speed The ball often requires cleaning
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The Mouse
Optical mouse Light shown onto mouse pad Reflection determines speed and direction Requires little maintenance
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The Mouse
Interacting with a mouse Actions involve pointing to an object Clicking selects the object Clicking and holding drags the object Releasing an object is a drop Right clicking activates the shortcut menu Modern mice include a scroll wheel
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The Mouse
Benefits Pointer positioning is fast Menu interaction is easy Users can draw electronically
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The Mouse
Mouse button configuration Configured for a right-handed user
Can be reconfigured Between 1 and 6 buttons Extra buttons are configurable
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Variants of the Mouse
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Variants of the Mouse
Trackballs Upside down mouse Hand rests on the ball User moves the ball Uses little desk space
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Variants of the Mouse
Track pads Stationary pointing
device Small plastic rectangle Finger moves across
the pad Pointer moves with the
pointer Popular on laptops
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Variants of the Mouse
Track point Little joystick on the keyboard Move pointer by moving the joystick
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Devices for the Hand
Pen based input Tablet PCs, PDA Pen used to
write data Pen used as
a pointer Handwriting
recognition On screen keyboard
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Devices for the hand
Touch screens Sensors determine
where finger points Sensors create an X,Y
coordinate Usually presents a
menu to users Found in cramped or
dirty environments
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Devices for the hand
Game controllers Enhances gaming experience Provide custom input to the game Modern controllers offer feedback Joystick Game pad
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Optical Input Devices
Allows the computer to see input Bar code readers
Converts bar codes to numbers UPC code
Computer find number in a database Works by reflecting light
Amount of reflected light indicates number
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Optical Input Devices
Image scanners Converts printed media into electronic Reflects light off of the image Sensors read the intensity Filters determine color depths
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Optical input devices
Optical character recognition (OCR) Converts scanned text into editable text Each letter is scanned Letters are compared to known letters Best match is entered into document Rarely 100% accurate
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Audiovisual Input Devices
Microphones Used to record speech Speech recognition
“Understands” human speech Allows dictation or control of computer Matches spoken sound to known phonemes Enters best match into document
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Audiovisual Input Devices
Musical Instrument Digital Interface MIDI Connects musical instruments to computer Digital recording or playback of music Musicians can produce professional results
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Audiovisual Input Devices
Digital cameras Captures images electronically No film is needed Image is stored as a JPG file Memory cards store the images Used in a variety of professions
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Essential Computer Hardware
Processing devices Brains of the computer Carries out instructions from the program Manipulate the data Most computers have several processors Central Processing Unit (CPU) Secondary processors
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Processing DevicesProcessing Devices
Cont.
Processors have two main parts
1.Control Unit
Interpret each instruction and take appropriate action
Traffic Control
1.Arithmetic logical unit
Perform arithmetic operation
And comparison too.
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Cont.
Registers
High speed storage
Temporary hold data
Different registers hold specific data
e.g Store fetching detail from where ALU performs computation
Sytem Clock
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Cont.
Heat Sinks:
Small ceramic or metal absorbs heat and disperse heat.
Heat Pipes:
Heat sinks consume more space
Liquid Cooling:
Flow of liquid that transfer heat fluid radiator type grill which cools the liquid and return to processor.
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Cont.
Parallel processing. Memory
Voltaile memory: loss contents
Non-Voltaile memory
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Essential Computer Hardware
Memory devices Stores data or programs Random Access Memory (RAM)
main memory Volatile Stores current data and programs More RAM results in a faster system
Read Only Memory (ROM) Permanent storage of programs Holds the computer boot directions
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Memory DevicesMemory Devices
RAM: Volatile MemoryRAM: Volatile Memory RAM: Non-Volatile MemoryRAM: Non-Volatile Memory
Cont.
Types of RAM:
• DRAM: Chips need to be re-energized.
i. SDRAM: faster, use system clock
ii.DDR SDRAM: transfer twice data for each clock.
iii.Rambus DRAM: use rambus channel, pipelining, parallel channels.
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Cont.
SRAM: need not to be re-energize, use transistors instead of capacitors.
Cache uses SRAM technology. Megnatoresistive RAM(MRAM):
Use magnetic pattern than electric charges.
More capacity, faster, consume less power.
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Cont.
Types of ROM:
Data can not be modify.
PROM: data is microcode
EEPROM:
Erase micocode by electrical signals.
Cache:
L1 cache: on processor. Stores 8KB to 128KB.
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L2 Cache:
On processor.
64KB to 16 MB
L3 cache: on moterboard.
2MB to 6MB
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Essential Computer Hardware
Storage devices Hold data and programs permanently Different from RAM Magnetic storage
Floppy and hard drive Uses a magnet to access data
Optical storage CD and DVD drives Uses a laser to access data
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Storage DevicesStorage Devices
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DRAM
Dynamic random-access memory (DRAM) is a type of random-access memory that stores each bit of data in a separate capacitor within anintegrated circuit. The capacitor can be either charged or discharged; these two states are taken to represent the two values of a bit, conventionally called 0 and 1. Since capacitors leak charge, the information eventually fades unless the capacitor charge is refreshed periodically. Because of this refresh requirement, it is a dynamic memory as opposed to SRAM and other static memory
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