CSCI-100 Introduction to Computing Hardware Part II.

CSCI-100CSCI-100Introduction to ComputingIntroduction to Computing

HardwareHardwarePart IIPart II

© Prentice-Hall, Inc

Digitizing the Real WorldDigitizing the Real World

ScannerScanner Digital cameraDigital camera Speech recognitionSpeech recognition Sensing devicesSensing devices Audio and video digitizersAudio and video digitizers

ContinuousContinuous & Discrete Signals& Discrete Signals


Audio InputAudio Input Computers can accept input from a microphoneComputers can accept input from a microphone An expansion card called a An expansion card called a sound cardsound card records records

and plays back sound files and plays back sound files Sound files contain digitized sound dataSound files contain digitized sound data Popular sound file formats include:Popular sound file formats include:

Windows WAVWindows WAV Moving Pictures Expert Group (MPEG)Moving Pictures Expert Group (MPEG) MP2 and MP3MP2 and MP3 Musical Instrument Digital Interface (MIDI)Musical Instrument Digital Interface (MIDI)


Audio DigitizersAudio Digitizers Audio digitizers capture Audio digitizers capture

spoken words, music spoken words, music and sound effects and and sound effects and convert them to convert them to digitized soundsdigitized sounds

These sounds can be These sounds can be stored in a computer’s stored in a computer’s memory and modified memory and modified with computer software with computer software

Sound CardSound Card

Functions: Functions: facilitates the input and output facilitates the input and output of audio signals to and from a computer of audio signals to and from a computer under control of computer programs under control of computer programs play previously recorded sound (translates a play previously recorded sound (translates a

digital file into sound)digital file into sound) to record new sound (translate sound into a to record new sound (translate sound into a

digital file)digital file)


Digital Cameras Digital Video

Digital Input: Digital Digital Input: Digital Cameras and Cameras and Digital VideoDigital Video


Video DigitizersVideo Digitizers Video digitizers capture input from video sources such as Video digitizers capture input from video sources such as

video camera and convert it to a digital signal that can be video camera and convert it to a digital signal that can be stored in memory and displayed on a computer screenstored in memory and displayed on a computer screen

Data RepresentationData Representation

Binary Numbers!!!Binary Numbers!!!

Sound Sound pitch pitch number number binary number binary number

Letter Letter number number binary number binary number

ImageImage color at each pixel color at each pixel number number binary binary numbernumber

Data RepresentationData Representation

But how many bits are needed to store But how many bits are needed to store n n symbols?symbols?

Or, how many bits are needed to represent n Or, how many bits are needed to represent n numbers?numbers?

loglog22nn


Output Devices: Engaging our SensesOutput Devices: Engaging our Senses

Output devices are peripheral devices that enable Output devices are peripheral devices that enable us to view or hear the computer’s processed dataus to view or hear the computer’s processed data Visual outputVisual output – Text, graphics, and video – Text, graphics, and video Audio outputAudio output – Sounds, music, and synthesized – Sounds, music, and synthesized

speechspeech


MonitorsMonitors

A monitor is a peripheral device which A monitor is a peripheral device which displays computer output on a screendisplays computer output on a screen

Types of monitors:Types of monitors: Cathode-ray tube (CRT)Cathode-ray tube (CRT) Liquid Crystal Display (LCD or flat-panel)Liquid Crystal Display (LCD or flat-panel)

CRT LCD


Cathode-ray tube (CRT)Cathode-ray tube (CRT)

Resemble televisions Resemble televisions Use picture tube technologyUse picture tube technology Less expensive than a LCD Less expensive than a LCD

monitormonitor Take up more desk space Take up more desk space

and use more energy than and use more energy than LCD monitorsLCD monitors


Screen TalkScreen Talk

Monitor sizeMonitor size - measured as a diagonal line - measured as a diagonal line across the screenacross the screen

PixelsPixels (or picture element) - tiny dots that (or picture element) - tiny dots that compose a picturecompose a picture

ResolutionResolution - the number of pixels displayed - the number of pixels displayed on the screen (the higher the resolution, the on the screen (the higher the resolution, the closer together the dots)closer together the dots)


Monitor SpecificationsMonitor Specifications

Screen sizeScreen size – The diagonal measurement of the screen – The diagonal measurement of the screen surface in inches (15, 17, 19, 21)surface in inches (15, 17, 19, 21)

ResolutionResolution – The sharpness of the image determined by – The sharpness of the image determined by the number of horizontal and vertical dots (pixels) that the number of horizontal and vertical dots (pixels) that the screen can display (800 x 600, 1024 x 768, 1600 x the screen can display (800 x 600, 1024 x 768, 1600 x 1200)1200)

Refresh rateRefresh rate – The speed at which the screen is redrawn – The speed at which the screen is redrawn (refreshed) and measured in Hertz (Hz) (60Hz, 75Hz)(refreshed) and measured in Hertz (Hz) (60Hz, 75Hz)


Image QualityImage Quality

Image quality is Image quality is affected by resolution affected by resolution and color depth (or bit and color depth (or bit depth)depth)

Color depth refers to Color depth refers to the number of bits the number of bits used to represent a used to represent a pixel.pixel.


PrintersPrinters

A printer is a A printer is a peripheral device that peripheral device that produces a physical produces a physical copy or copy or hard copyhard copy of of the computer’s outputthe computer’s output


Inkjet Laser

Types of PrintersTypes of Printers

Inkjet printer,Inkjet printer, also called a also called a bubble-jetbubble-jet,, makes makes characters by inserting characters by inserting dots of ink onto paper dots of ink onto paper

Letter-quality printouts Letter-quality printouts Cost of printer is Cost of printer is

inexpensive but ink is inexpensive but ink is costlycostly

Laser printerLaser printer works like a works like a copier copier

Quality determined by dots Quality determined by dots per inch (dpi) producedper inch (dpi) produced

Color printers available Color printers available Expensive initial costs but Expensive initial costs but

cheaper to operate per cheaper to operate per pagepage

ModemModem

Connects you computer to the outside Connects you computer to the outside worldsworlds

Modulate - Converts a digital signal into an Modulate - Converts a digital signal into an analog oneanalog one

Demodulate - Converts an analog signal to Demodulate - Converts an analog signal to a digital one.a digital one.

ModemModem = = MoModulate dulate demdemodulateodulate ExampleExample

ModemModem

Speed is measured in BPS (Bits per Speed is measured in BPS (Bits per second)second)

Standard speed is 56k BPS Standard speed is 56k BPS


Storage DevicesStorage Devices

Storage devices are categorized by:Storage devices are categorized by:The type of operations they performThe type of operations they perform

The method they use to access the The method they use to access the informationinformation

The technology they useThe technology they use

Their location in the storage hierarchyTheir location in the storage hierarchy

Their capacity and speedTheir capacity and speed


Sequential vs. Random Access Sequential vs. Random Access StorageStorage

SequentialSequential –– Storage devices that read and write Storage devices that read and write data in a serial (one after the other) fashiondata in a serial (one after the other) fashion

Random-AccessRandom-Access – Storage devices that read and – Storage devices that read and write data without going through a sequence of write data without going through a sequence of locationslocations

Tape Drive – sequential storage

Hard Disk – random-access storage

Floppy Disk Drive – random-access storage


Storage Technologies: Magnetic Storage Technologies: Magnetic and Opticaland Optical

Magnetic Magnetic – Storage devices use disks or tapes that – Storage devices use disks or tapes that are coated with magnetically sensitive materialare coated with magnetically sensitive material

Optical Optical – Storage devices that use laser beams to – Storage devices that use laser beams to read patterns etched into plastic disksread patterns etched into plastic disks

Magnetic Storage Optical Storage – CD/DVD drive


Optical Disk StorageOptical Disk Storage

Microscopic indentations called Microscopic indentations called pitspits scatter the laser scatter the laser beam’s light. A light-sensing device receives no light beam’s light. A light-sensing device receives no light from the pits. A signal is sent to the computer from the pits. A signal is sent to the computer corresponding to a 0 in the binary systemcorresponding to a 0 in the binary system

Flat, reflective areas, called Flat, reflective areas, called landslands, bounce the light , bounce the light back to the light sensing device, which sends a signal back to the light sensing device, which sends a signal corresponding to a 1 corresponding to a 1

Cross-section of a disk Disk surface magnified


CD-ROM Discs and DrivesCD-ROM Discs and Drives CD-ROM stands for Compact CD-ROM stands for Compact

Disc-Read Only MemoryDisc-Read Only Memory

CD-ROM drives can not write CD-ROM drives can not write data to discsdata to discs

They are capable of storing They are capable of storing ~700 MB of data~700 MB of data

They are used for storing They are used for storing operating systems, large operating systems, large application programs, and application programs, and multimedia programsmultimedia programs

CD-ROMs and RecordablesCD-ROMs and Recordables

1st CD-ROMs had speeds of 600 1st CD-ROMs had speeds of 600 millisecond access time and transfer rates millisecond access time and transfer rates of 150 KB.of 150 KB.

32 times the original speed (32X).32 times the original speed (32X).


CD-R and CD-RW Discs and CD-R and CD-RW Discs and RecordersRecorders

CD-RCD-R Discs can be read Discs can be read

and written toand written to Discs can only be Discs can only be

written to “once”written to “once” CD-R drives are CD-R drives are

capable of reading capable of reading and writing dataand writing data

CD-RWCD-RW Discs can be read and Discs can be read and

written towritten to Discs are erasableDiscs are erasable Discs can be written to Discs can be written to

many timesmany times CD-RW drives are CD-RW drives are

capable of reading, capable of reading, writing, and erasing writing, and erasing datadata


DVD-ROM Discs and DrivesDVD-ROM Discs and Drives DVD stands for Digital Video DiscDVD stands for Digital Video Disc DVD technology is similar to CD-DVD technology is similar to CD-

ROM technologyROM technology DVDs are capable of storing up to DVDs are capable of storing up to

17GB of data17GB of data The data transfer rate of DVD drives The data transfer rate of DVD drives

is comparable to that of hard disk is comparable to that of hard disk drivesdrives

DVD-R and DVD-RW drives have DVD-R and DVD-RW drives have the ability to read/write datathe ability to read/write data

PortsPorts

Serial port: one bit at a timeSerial port: one bit at a time Parallel portParallel port USB port (Universal serial port): USB port (Universal serial port):

USB can connect computer peripherals (such as mice, keyboards, USB can connect computer peripherals (such as mice, keyboards, digital cameras, printers, personal media players, flash drives, digital cameras, printers, personal media players, flash drives, Network Adapters, and external hard drives to the computer. Network Adapters, and external hard drives to the computer.

For many of those devices, USB has become the standard For many of those devices, USB has become the standard connection method. connection method.

USB was designed for personal computers, but it has become USB was designed for personal computers, but it has become commonplace on other devices such as smartphones, PDAs and commonplace on other devices such as smartphones, PDAs and video game consoles, and as a power cord.video game consoles, and as a power cord.

Other types of ports.Other types of ports.


CSCI-100 Introduction to Computing Hardware Part II.

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