Input, Process, Output
Supplemental Lecture Notes
Typical System
Computer case
Monitor
Printer
Speakers
Modem
Keyboard
Mouse
Computer Components
Power supply
Hard drive
Expansion card
Expansion slot
System board
CD-ROM or DVD-ROM
Floppy disk
Drive bay
Central Processing Unit (CPU)
Random access memory (RAM)
Power Plays
The capacity of a power supply is measured
in watts
Computer uses 250; light bulb uses 60
Can use
Surge protector
UPS
Ports
Ports are connectors at the back of a
computer system that you use to plug in an
external device. This allow instructions and
data to flow between the computer and the
device
Any Port in a Storm
Parallel port – 25 holes; female connector; LPT1; printer or
storage devices
Monitor port
Keyboard port
Serial port – 9 or 25 pins; male connector; COM1; mouse
or modem
Game port
Network port
USB port
127 devices
Printer, modem, joy stick
Growing
An expansion card is a circuit board that
lets you add new features to a computer
Video
Modem
Sound
Network Interface
Upgrades
Upgrading refers to replacing an old or obsolete
component with a newer component to improve
the efficiency of the computer
Upgrading also can include adding a new
component like a tape drive or DVD to increase
the capabilities of a computer
Increasing the amount of memory in a computer is
one of the most effective upgrades you can
perform
Input and Output
Chapter 2
Mouse Actions
Click – selects
Right click – displays commands
Double click – opens
Drop and Drag – moves items on screen
Mice
Types
Conventional
Wheel mouse
Wireless mouse
Programmable mouse – e.g. three buttons
Optical sensor mouse
Other devices
Touchpad
Trackball
Pointing stick
Keyboards
There are 101 keys on a keyboard to help you
input information
Function keys let you perform specific task
Can use CNTL-x shortcuts to execute
commands
CNTL-C – copy
CNTL-X – cut
CNTL-V – paste
Windows key will quickly display the start
menu
Printers
Speed of a printer is measured in pages per minute
(PPM). A higher speed represents faster output
Resolution determines the quality of images
A higher resolution results in sharper images
Printer resolution is measured in dots per inch (dpi)
600 dpi is acceptable; 1200 is better for images
Resolution expressed with two numbers represents dots
per inch across and down
Types of Printers
Ink-jet: has a print head that sprays ink
through tiny nozzles onto a page
2 to 10 pages (ppm)
360 to 2400 dots per inch
Color printers spray cyan, magenta, yellow
and black to create different colors
Laser-printer
Works like a photo copier
Speed of 4 to 16 pages
Have a CPU
600 to 2400
Memory – 2mb to 8 Mb
Other Types
Dot matrix
Print head contains small blunt pins that strike
an inked ribbon
Useful for multi-part forms
LED printer
Similar to lasers but cheaper
Color photo printer
Multifunction Printer
Print Buffer and Spoolers
Printer buffer: section of memory printer
stores information waiting to print
Printer spooler: program on your computer
that stores information waiting to print
Stores more information than the buffer
One spooler for each connected printer
Monitors
Video cards translate instructions from
the computer into a form Most
computes the monitor can understand
require at least 2 mb of video card
memory
Accelerated Graphics Port (AGP) – uses
AGP bus to communicate directly with
main memory
3D Graphics Accelerator has chip called a
GPU optimized for 3-D graphics
Monitor Metrics
The smaller the dot pitch, the crisper the
image
0.28mm is acceptable
Refresh rate is measured in hertz (Hz)
Times per second computer redraws the image
72 Hz or more is acceptable
Resolution
Amount of information a monitor can display
Measured by the number of horizontal and vertical
pixels
Monitors switch settings based on the resolution
and refresh rate of video card
Video card determines number of colors a monitor
can display
256 suitable for most home use
24-bit displays more colors than eye can distinguish
Communications
Modems let a computer exchange
information through telephone lines
Speed of a modem determines how fast it
sends and receives messages
56,000 bps (56 Kbps)
V.90 standard: receive 56K and send 33.6K
Speed at which information flows depend on
the quality of the phone line
A modem needs a communications
package to manage the transmission of
information
Data compression – squeezes together data
High-speed Connections
ISDN – Integrated Services Digital Network
Digital phone line
56 Kbps to 128 Kbps
Cable Modem
Same cable as TV
4000 Kbps
DSL – Digital subscriber line
High speed digital phone line
1000 – 6000 Kbps
Satellite
Sound Cards
Sampling Rate: at least 44.1 KHz
Full-duplex
Talk and listen at same time
Musical Instrument Digital Interface (MIDI)
support
Wavetable synthesis
Actual recordings
FM synthesis
Imitated sounds
TV Tuner Cards
Require a video card to operate
Scanners
A scanner is a device that reads
images and text into a computer
Most scanners come with Optical
Character Recognition (OCR) software.
This software places scanned text into a
document that can be edited in a word
processor
Color dept is measured in bits and
indicates the number of colors a scanner
can detect
36 bit color depth is acceptable
Resolution
Resolution determines the amount of detail
a scanner can detect
Ranges from 600 dpi to 2400 dpi
You usually don’t need to scan at a higher resolution
than a printer can produce or a monitor can display
– Most monitors are 73 dpi
– Printers vary
Cameras
Resolution is measured in megapixels
1000 x 1000 pixels
1, 2 and 3 megapixel cameras are available
Digital video cameras use a Charged Coupling Device
(CCD) to capture video
Quality depend on amount of detail a CCD can detect
Most CCD’s have resolution between 250,000 and 700,000 pixels
Web cameras – resolution and speed determine quality of
image
Common transfer rates
15 frames per second at 640 x 480 pixels
30 frames per second at 352 x 288 (clearer but smaller)
MP3
Sound format used to CD-quality music
over the Internet
Compresses sound
Commonly 64 bit memory
USB and Firewire
High-speed ports that allow information to quickly
transfer between a computer and an external
device
USB
Supports up to 127 device
– USB 1.0: 12 megabits per second
– USB 2.0: 480 Mbps
FIREWIRE
63 devices at 400 Mbps
Can purchase Firewire expansion card
Processing
Chapter 3
CPU (Central Processing Unit)
Processes instructions, performs calculations,
and manages the flow of information
Performance:
CPU speed is a major factor in determining how fast a
computer operates (faster the speed, faster computer
operates)
Measured in megahertz (MHz) A clock cycle relates to the
clock that controls the timing in the microprocessor.
For example, a 900MHz (megahertz) clocked
microprocessor generates 900 million clock cycles per
second.
Each generation of CPU is more powerful than the
one before. It's clock cycles are faster at a given speed
Processing
The Central Processing Unit (CPU) is the
main chip in a computer
Processes instructions
Performs calculations
Manages the flow of information
Types of CPUs
Intel Pentium Processor
Speeds of 450 MHz to 1.13 GHz
Intel Celeron
Needs of home machines (500-700MHz)
AMD Athlon Processor
Business and home use
AMD Duron Processor
Home use
VIA Cyrix Processor
Inexpensive CPU
Processing
Random Access Memory – Temporarily stores data
inside a computer
Constantly overwritten
Measured in megabytes (MB)
64 minimum these days100 MHz (millions of cycles per
second)
Dynamic RAM is type of memory chip that makes up
memory in many computer systems. Access speed measured
in megabits
Most system boards can support access speed of Single Inline
Memory Module (SIMM) – 9 memory chips
Dual Inline Module (DIMM) – 18 memory chips
If you have limited memory or you have many
programs open, your computer may need to use part of
the hard drive to simulate more memory
Using Memory Cache
1. Look through documents on your desk
(internal cache)
2. Look through documents in your desk
drawer (external cache)
3. Looking through documents in your filing
cabinet (RAM)
Using Memory Cache
1. Look through documents on your desk
(internal cache)
2. Look through documents in your desk
drawer (external cache)
3. Looking through documents in your filing
cabinet (RAM)
Math Coprocessors
A special processing unit that assists the CPU in
performing certain operations.
A math coprocessor is a chip or part of a chip that
specializes in doing math. Hardware that attaches to
the motherboard or is part of the CPU.
Extends the capabilities of a CPU in a transparent manner.
Performs mathematical computations, particularly floatingpoint operations.
Besides being able to add, subtract, multiply and divide
floating-point numbers, they can also operate on them to
perform comparisons, square roots, logarithms, sine, cosine,
tangent, absolute value, and remainders
Also called numeric coprocessors or
floating point units (FPU).