2. Definition of a Computer
“A computer is an electronic device, operating
under the control of instructions stored in its
own memory unit, that can accept data
(input), process data arithmetically and
logically, produce information (output) from
the processing, and store the results for
future use.”
3. Functions of a Computer
• Four operations performed
• The four operations are referred to as the
information processing cycle: Input,
Process, Output, and Storage.
• Computers transform raw data into
information
• People who use this information are
referred to as end users, computer users or
users
4. Introduction to Computer Hardware
• Hardware vs Software
Hardware is everything you can touch and see
Examples: Monitor, hard drive, CD-ROM, computer
cables, keyboard, mouse, modem, printer, etc.
5. Software
• Software are programs & applications
– Part of computer that cannot be seen
– Needed for computer to function
– Designed to solve common or custom problems
– System vs Application Software
6. Systems Software
• Consists of programs to control the
operation of computer
• Operating System - DOS
• Booting Process
• GUI - Graphical User Interface
7. Application Software
• Word Processing Software
• Electronic Spreadsheet Software
• Database Software
• Presentational Software
• Communication Software
• Electronic Mail Software
8. Components of a Computer
• There are four components to a computer
– Input Devices
– Processor Unit
– Output Devices
– Auxiliary Storage Devices
9. Input Devices
• Input Devices enable the user to enter data
into memory
• Examples of input devices:
– Keyboard
– Mouse
– Scanner
– Touch Screen Input
– OCR
10. The Processor Unit
• The Processor Unit is comprised of two
components:
– Central Processing Unit (CPU)
– Memory
11. CPU
• Interprets instructions to the computer
• Performs logical and arithmetic operations
• Causes the input and output operations to
occur
• A Pentium Pro Microprocessor can perform
approximately 250 million instructions per
second (MIPS)
12. CPU TYPES
• Intel, Advanced Micro Devices (AMD),
Motorola, Cyrix
• X86 family of processors: 8080, 8086,
8088, 80286, 80386, 80486, Pentium (P5),
Pentium Pro, Pentium II
• MMX - additions to the CPU programming
that allow for better and faster multimedia
tasks like graphics and sound.
13. Computer Memory
• RAM - Random Access Memory
– Computer’s primary storage of data to be
processed
– Silicon chips that store data and instructions as
electronic currents
– CPU can manipulate electrical currents
– Contents of RAM will be lost when power is
turned off
14. Computer Memory
• Usually measured in MB or KB (e.g.: 8 MB
of RAM)
• 1000 KB approximately = 1 MB
• 1 MB contains approximately 500 pages of
text information.
• More RAM = faster processing rate
• Applications determine how much RAM
needed
15. Computer Memory
• ROM - Read Only Memory
– Instructions and data are hard coded on the
silicon chips
– Examples: BIOS (Basic Input-Output
System)
• gives computer the initial instructions to get it
started once computer is turned on.
16. Cache
• Temporary holding area where the system
stores frequently accessed information
• Allows the processor to operate faster
• Size measured in KB (e.g. 256K or 512 K)
• Cache associated with the terms L1 or L2
• L1 is internal to the microprocessor
• L2 is separate from the microprocessor
17. Output Devices
• Output Devices make the information
resulting from processing available for use
• Examples of Output Devices:
– Printers
– Computer Screens
– Speakers
18. Computer Screens
• Also called monitor or Cathode Ray Tube
(CRT)
• Flat panel screens - LCD (Liquid Crystal
Display)
• Screen is made up of pixels
19. Auxiliary Devices
• Also know as Secondary Storage Devices
• Examples of Auxiliary Devices:
– Floppy Disks
– Hard Drives
– CD-ROM
– Tape Backup Drives
– ZIP Drives
21. Floppy Disks
• Disadvantages:
– Slow access time
– Low capacity
• Access time is measured in milliseconds
(ms)
• Formatting and protecting floppy disks
22. Hard Disks
• Secondary Storage Device
• Able to store large amounts of data
• Internal vs External
• Storage measured in MB’s or GB’s
• Access time measured in milliseconds (9-28
ms)
• Compression programs are used to save
storage space
23. CD-ROM
• Compact disk read-only memory disks are
used to store large amounts of prerecorded
information
• Since programs are getting bigger, it is a
good medium for storage of programs
• Drive Speeds: 4X, 6X, 8X, 10X, 16X, 20X,
24X
• Read-Write CD’s are now available
24. Tape Backup Drives
• Used primarily for backup important
information on HD as a precaution against
system failure or crashes
• Can be used to archive information
• Can store large amounts of information, but
access time is slower than floppy or hard
disks
25. ZIP and JAZ Drives
• The Zip drive uses special high capacity
disks (100MB) to store information
• Access times vary, but oftentimes are as fast
as hard drive
• Extremely convenient for transferring or
storing large amounts of data
• JAZ drives similar to Zip, but can store up
to 1 GB of info on 1 disk
26. Monitor
• Measured diagonally in inches
• Actual viewable area is less
• Monochrome
– Black and white display
• Color Monitors
– SVGA, VGA, EGA, CGA:
27. Monitor
• Image consists of small dots or pixels
• More pixels = clearer image
• Monitor needs monitor controller
(Video/Monitor card) to function
– Memory on monitor controller accelerates
display on image
– Accelerator chip speeds up display as well
28. Modem
• Device that allows transfer of data over
phone lines (internet access, faxing, etc..)
• BAUD - Speed of modem measured in bits
per second or bps
• Examples: 14.4 bps (or 14,400 bits per
second), 28.8 bps, 33.6 bps, etc..
• Internal or External
29. Modem
• 56K Modems are now available, but actual
speeds depend on the phone lines and the
technology used by your ISP (Internet
Service Provider)
30. Next Class
• We will meet in TAH 1007
• Bring your book and a floppy disk
• Read first two chapters of textbook
