CS (140) - INTRODUCTION TO COMPUTERS
Teacher: Dr. Shrestha
Materials for class (3)
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GOALS FOR TODAY:
Take examination (2) on materials from Chapters (3) and (4)
Learn materials from Chapters (5) and (6)
Lecture and Lab
HOMEWORKS DUE TODAY:
Graphics embedded invitation card prepared by using PAINT
Decimal to binary and binary to decimal conversion
Mathematical equations
Exercises based on your visit to following websites:
MICROSOFT'S WINDOWS -
LINUX -
WEB SHOPPING -
ACTIVE DESKTOP -
MICROPROCESSORS -
UNIVERSAL SERIAL BUS -
DESKTOPS AND NOTEBOOKS -
TV TUNER CARDS AND VIDEO CLIPS -
Web site - http://www.mhhe.com/it/oleary/exercise.mhtml
ASSIGNMENT:
Read and review materials from Chapters (5) and (6)
Test (3) on these materials next class
Exercises on Internet
Construct a table by using WORD
Use EXCEL to prepare a table and a graph
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Save days' work in your diskette !
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CHAPTER (5) - INPUT AND OUTPUT
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KEY IDEAS
KEYBOARD ENTRY
Keyboard entry can be categorized as keyboards and terminals.
Keyboards
Both traditional and natural keyboards have various types of keys
including escape, function, numeric, windows, spacebar, and
navigator. They also include toggle keys and combination keys.
Terminals
These devices connect to host computer or server. There are four
kinds of terminals:
(1)DUMB- sends and receives only; no processing
(2)INTELLIGENT - sends, receives, and processes; popular type is Net PC.
(3)NETWORK - provides low cost alternative to intelligent terminal.
(4)INTERNET - accesses Internet and displays on a television set; does
not require microcomputer. It is also called as Web terminal or Web
appliance.
DIRECT ENTRY
Direct entry devices can be categorized as pointing, scanning, or
voice-input.
Pointing
Pointing devices allow users to directly use their hand to input
data. Most common use is the mouse. Three similar devics are
trackballs, touch surfaces, and pointing sticks. Others include:
Joysticks - control game action by varying pressure, speed, and direction
Touch screens - touching finger to screen control operations
Light pens - directed at screen controls operations
Digitizers - convert images to digital data
Digital cameras - record photos on disk and in memory
Webams - used for Internet broadcasting
Digital Video cameras - record motion digitally on tape, on disk, or in
memory
Digital notebook - electronic pad records handwriting as digital data
Scanning
Scanners convert images to digital data. Widely used scanning devices
include image scanners, fax machines, bar-code readers, Magnetic-ink
character recognition (MICR), Optical character recognition (OCR), and
Optical Mark recognition (OMR) devices.
Voice-Input
These devices convert a person's spoken words into digital data. Voice
recognition systems are a combination of hardware and software that allow
users to operate microcomputers and create documents using voice
commands. Two types are:
Discrete-speech recognition system - recognizes only individual words
Continuous-speech recognition system - recognizes individual words and
phrases in context
MONITORS
Monitors create images on screen by individual dots called pixels. Dot
pitch is the distance between pixels. The three most
common pixel standards are:
Pixels - Picture - Elements
Standard VGA (Video Graphics Array) - Pixels 640x480 - 13 inch monitor
Standard SVGA (Super Video Graphics Array) - Pixels 800x600 - 15 inch
monitor
Standard XGA (eXtended Graphics Array) - Pixels 1024x768 - 17 and 19 inch
monitor
Standard SXGA (Super eXtended Graphics Array) - Pixels 1280x1024 - 19 and
21 inch monitor
Standard UXGA (Ultra eXtended Graphics Array) - Pixels
1600x1200 - 19 inch monitor
Cathode Ray Tubes (CRT)
CRTs are the most common type of monitor. Similar to televisions
in size and technology, they are typically placed on a system unit
or directly on a desk. Primary advantages of CRTs are low cost and
excellent resolution or clarity.
Flat-Panel Monitors
Flat-panel monitors are widely used for portable computers and
are becomming more popular for desktop systems because they are less
bulky and flat. Two basic types are:
Passive-matrix - require little power but images not as sharp
Active-matrix - require more power, are more expensive, but
produce sharper images
PRINTERS
Output from monitors is called soft copy. Outptut from a printer is
called hard copy. Three widely used types
are:
(1) PRINTER:
Ink-jet
CHARACERISTICS:
High color quality, inexpensive, sprays drops of ink on paper
TYPICAL USE:
Internal and external communications, advertising pieces
(2) PRINTER:
Laser
CHARACTERISTICS:
Very high quality, uses photocopying process
TYPICAL USE:
Desktop publishing, external documents
(3) PRINTER:
Thermal
CHARACTERISTICS:
Very high quality, uses heat elements on special paper
TYPICAL USE:
Art and design work
PLOTTERS
Plotters produce multicolor bar charts, maps, architectural
drawings, and three-dimensional illustrations. Four types are:
Pen
Pen plotters create a drawing by moving a pen or pencil over
drafting paper. They are the most popular and least expensive.
Ink-Jet
Ink-jet plotters are fast, quiet, and very good at producing
solid-color output. The jets, however, can become clogged and
require maintenance.
Electrostatic
These plotters use electrostatic charges to create high quality
and high volume output on specially treated paper. Costly chemicals
considered dangerous to the environment, however, are required for
the development process.
Direct-Imaging
Direct-imaging plotters use electrically charged pins to create
two-color output on special heat-sensitive paper. Due to expensive
paper requirements and limited color output, these plotters are
speciality devices.
VOICE-OUTPUT
Voice-output devices make sounds resembling human speech. The
most widely used devices are stereo speakers and headphones.
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CHAPTER (6) - SECONDARY STORAGE
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KEY-IDEAS
FLOPPY DISK
Floppy disks are also known as diskettes or simply as disks. They are
inexpensive, direct access, and removable storage media. Floppy disks
are primarily used to save and transport documents.
Today's Standard
Today's standard floppy disk is the 1.44 MB 3.5 inch 2HD. It is by
far the most widely used floppy disk today. Due to its relatively low
storage capacity, however, it is expected to be replaced by higher
capacity floppy disks.
Tomorrrow's Standard
Three types known as floppy disk cartridges are competing to become
the next standard. They are:
ZIP DISKS - 100 MB capacity; considered by many to be the leading contender to
replace today's storage standard
SUPERDISKS - 120 MB capacity; SuperDisk drives are able to read today's
standard disks.
HIFD - 200 MB capacity; HiFD drives are able to read today's standard
disks.
Parts of a Floppy Disk
Data is recorded on disk in rings called tracks. Each track is
divided into wedge-shaped sections known as sectors. The process of
preparing a disk with tracks and sectors is called formatting or
initializing.
HARD DISK
Hard disks provide direct and fast access to data on rigid disks.
Compared to floppy disks, they are much faster and provide much greater
storage. Hard disks are typically used to store programs and large
amounts of data. Three types are internal, hard-disk cartridge, and
hard-disk pack.
Internal Hard Disk
An internal hard disk is also known as a fixed disk because it is
attached within the system unit. They are typically enclosed with one or
more metallic disks to protect against a head crash.
Hard-Disk Cartridge
Unlike internal hard disks, hard-disk cartridges are removable and
only the number of cartridges limits the amount of storage capacity. Two
well-known hard-disk cartridges are Jaz and SparQ.
Hard-Disk Pack
Hard-disk packs consist of several platters and have a capacity that
greatly exceeds both internal and hard-disk cartridges. Hard-packs are
used primarily by minicomputer and mainframe computer systems.
Performance Enhancements
Three ways to improve hard disk performance are:
While floppy and hard disks use magnetic changes to represent data and
programs, optical storage uses reflected light.
OPTICAL DISK
Optical storage uses reflected light. Pit and land on the disk's
surface represent 1 and 0. A laser directs light on the surface, and the
amount of reflected light indicates either a 0 or 1.
Compact Disk
Compact Diskes or CDs are the most widely used optical disks today.
With a typical capacity of 650 MB, there are three basic types:
CD-ROM - Compact Disk-Read Only Memory; widely used to distribute large
databases, references, and large application packages
CD-R - Compact Disk Recordable; also known as WORM (Write Once Read Many),
used to archive large amounts of data
CD-RW - Compact Disk Rewriteable; reusable; used to create and edit large
multimedia presentations
Digital Versatile Disk (DVD)
Digital Verstile disks are similar to the CDs with far greater
capacity. Present capacity is 4.7 GB moving to 17 GB soon.
Three basic types are:
DVD-ROM - Digital Versatile Disk - Read Only Memory; like
CD-ROM with over seven times the capcity; widely used to
distribute full length feature films with theater-quality video
and sound
DVD-R - Digital Versatile Disk - Recordable; due to higher
cost not as popular as CD-R; expected to replace CD-R as
prices decline
DVD-RAM & DVD-RW - Digital Vesatile Disk - Random Access
Memory & Digital Versatile Disk Rewriteable; two recently
introduced standards for reusable DVD disks; used to develop
very large scale multimedia projects
MAGNETIC TAPE
Magnetic tape is a sequential access storage medium. It is used
primarily to back up or duplicate data and programs. Two types are
streamers and tape reels.
Magnetic Tape Streamers
Magnetic tape streamers are also known as backup tape cartridge units.
Used almost exclusively with microcomputers, these units use tape
cartridges to back up hard disks.
Magnetic Tape Reels
Magnetic tape reels are used to back up minicomputer and mainframe
storage devices. The tape is run on magnetic drives or magneetic tape
units.
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