An Introduction to Microcomputers

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An Introduction to Microcomputers
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Have You Had Contact With a Computer Today?
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What Is a Computer?
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Input
Output
Processor (CPU)
Main Memory
Auxiliary Storage
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I. Hardware

• The physical components of a computer
• Anything that you can touch or see
• Includes the processor, memory, input-output
  devices, and storage

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Input
Output
Processor (CPU)
Main Memory
Auxiliary Storage
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A) The Central Processing Unit (CPU)

• The computer brains
• Two components
• l control unit
• l arithmetic/logic unit

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• Computers are not capable of thought
• Computers can only recognize two distinct states
  produced by
• l electricity
• l magnetic polarity
• l reflected light

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B) Memory

• 1) read only memory (ROM)
• l permanent
• l non-volatile
• l installed by manufacturer and cannot be
  altered
• l holds the programs that start or boot the
  computer

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• 2) Random Access Memory (RAM)
• l Temporary / Volatile
• l Short-term holding area used as the
  workspace
• l Holds data files and programs currently in
  use
• l Random Access vs. Sequential Access

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• 3) Measuring Memory
• l Bit The smallest unit of memory
• l Byte 8 bits
• l One byte is the smallest block of memory
  addressed. One byte is equivalent to a single
  character.

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• l Kilobyte 1024 Bytes (KB)
• l Megabyte 1,048,576 Bytes (MB)
• l Gigabyte 1,073,741,824 Bytes (GB)
• l Terabyte 1,099,511,627,776 Bytes (TB)

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Input
Output
Processor (CPU)
Main Memory
Auxiliary Storage
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• B) Storage
• 1) Magnetic Disks
• l The disk surface is coated with millions
  of tiny iron particles
• l The read/write head charges these pieces
  of iron to store data
• l The read/write head is charged by the
  disk to read data

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Floppy Disk
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• A) 3½ inch floppy disk
• - Hardshelled diskette
• l three storage capacities
• - 720 KB double-sided,
  Double density (DSDD)
• - 1.44 MB double sided, High
  density (DSHD)
• - 2.88 MB disks
• l portable

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• b) Hard Disks ( Fixed)
• l Non-Removable Disk Storage
• l Primary storage device for all
  microcomputers today
• l Faster retrieval than a floppy
• l Much greater storage capacity than a
  floppy disk
• - 80 MB to 47 GB

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External Zip Drive
Internal Zip Drive
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• C) ZipÔ Cartridge
• l Larger capacity than a floppy
• l 100 MB 250 MB
• l Internal or external drive
• l Portable
• l Inexpensive

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External Jaz Drive
Internal Jaz Drive
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• C) JazÒ Cartridge
• l Larger capacity than a ZipÔ
• l 1 GB 2GB
• l External drive
• l Portable
• l Fast data Retrieval
• l More expensive than a ZipÔ

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Magnetic Tape Drive
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• e) Magnetic Tape
• l Data is stored on the surface of magnetic
  tape
• l Sequential access ( Slow )
• l Large Capacity ( 12 to 1260 GB)
• l Best used for rarely used data or hard
  disk backup

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• 2) Optical Storage Devices
• l Use laser beams to read data from the
  disk
• l Have one long tract that starts at the
  outer edge and spirals inward toward the
  center
• l Are the main alternatives to magnetic
  storage today

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CD ROM
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• a) CD-ROM
• l Compact DiskRead Only Memory
• l Same technology as music CDs
• l Can store up to 650 MB
• l Relatively fast data retrieval

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• b) DVD
• l Digital Versatile Disk
• l Can hold from 4.7 to 17 GB
• l can be used to store massive computer
  applications or full- length movies complete
  with digital sound
• l Relatively fast data retrieval

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• c) Other Optical Storage
• 1) WORMWrite Once, Read Many
• l Once etched into the surface, data
  cannot be changed
• l Vast permanent storage
• 2) Magneto-Optical
• l A CD capable of being rewritten

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CD Writers
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Input
Output
Processor (CPU)
Main Memory
Auxiliary Storage
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Keyboard
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• C) Input Devices
• 1) Keyboard
• l Most common input device
• l 4 Parts to the standard keyboard
• 1) Alpha-numeric keys
• 2) Numeric Keyboard
• 3) Function Keys
• 4) Cursor- movement keys

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• 2) Mouse
• 3) Track Ball
• 4) Light Pen
• 5) Touch Screen
• 6) Image Scanner
• 7) Voice Recognition
• 8) Bar-code readers
• 9) Optical Character Readers

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Input
Output
Processor (CPU)
Main Memory
Auxiliary Storage
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• C) Output Devices
• 1) Monitor
• l CRT or LCD
• l Monochrome or Color
• l Display is made up of pixels (
  picture elements)
• l Video card is the interface between
  monitor and CPU

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• 2) Printer
• l Three principal types
• a) Dot-Matrix
• l impact printer
• l least expensive
• l lowest quality

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• b) Laser
• l non-impact printer
• l highest quality print
• l quiet and fast
• l most expensive
• C) Ink-Jet
• l good quality, speed
• l less expensive than laser
  printers

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• 3) Sound
• 4) Voice Synthesis

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Input
Output
Processor (CPU)
Main Memory
Auxiliary Storage
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I. Software

• Software makes a computer useful
• Step-by-step instructions
• Stored as files on a disk
• Loaded into and executed from RAM
• Two types System and Application

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A) System Software

• l Computer oriented software
• l Coordinates actions of Hardware
  components
• l Runs the application software
• l Include
• Operating Systems
• System Utilities

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B) Application Software

• l User Oriented
• l Purpose Specific
• l Examples
• Microsoft Office
• Word Perfect
• Netscape
• Turbo Tax