5. Progress of Technology through
Time
ENIAC
=
Current Technology
Composed of 17,000 vacuum tubes, 70,000 resistors, and
10,000 capacitors, the ENIAC (Electronic Numerical
Integrator and Computer) weighed over 30 tons and took up
1800 square feet of floor space. Completed in 1945, the
ENIAC was used for ballistics work and later on for weather
prediction.
Today’s technology uses vast numbers of
electronic components in the form of miniaturized
integrated circuits contained on silicon chips.
Modern day desk calculators exceed ENIAC’s
computational power and speed by far.
8. Components of a VGA Monitor
Electron Guns
Three electron guns located
at the back of the monitor’s cathode-
ray tube send out three electron beams
for each of the primary colors.
Magnetic Deflection Yoke
This mechanism uses electromagnetic
fields to bend the paths of the electron
streams.
Shadow Mask
The beams pass through holes in a
metal plate called a shadow mask.
The mask keeps the electron beams
precisely aligned, so that colors are
accurate. The monitor’s dot pitch
is a measure of how closely the
holes are spaced apart.
Phosphor Coating
The phosphor coating is a material
that glows when struck by an electron
beam. The screen is made up of
triads of red, green, and blue phosphor
dots. As the energy in the electron
beam increases, the phosphor dots
glow brighter. To create different
colors, the intensity of each of the
three beams is varied.
9. Computer Memory
SIMM
Single Inline Memory Modules are the most
popular memory module of present day
computers. The small circuit board contains
three to nine DIP chips. SIMMs range in size
from 4MB to 32MB of memory.
DIP
Dual Inline Pin memory modules were once
used for main memory in older computer
systems. Now they are used as components
on SIMM chips and are also used in cache
RAM.
ROM
A Read Only Memory storage device has
instructions permanently embedded in its
circuits. ROM chips contain programs that
start the computer and perform system
diagnostics.
Virtual Memory
When a computer runs out of real memory
(storing information in RAM), it employs
a software technique to generate virtual
memory, storing and swapping information
on the computer’s hard drive.
10. Hard Disk Storage
Sealed Metal Housing
The housing protects the internal
components from dust particles that could
block the gap between the read/write heads
and the platters, causing the hard drive to
crash.
Drive Spindle
The drive spindle is connected to a
motor which spins one or more
magnetically coated platters at several
thousand revolutions per minute. More
platters mean greater disk storage
capacity.
Head Actuator
This component moves the
collection of read/write heads
across the surface of the platters
with extreme accuracy. It aligns
the heads with the tracks that
lie in concentric circles
on the platters.
Read/Write Head
These read/write heads move in
unison across the surfaces of the
platters. The heads write data to
the platters by aligning magnetic
particles on the surface and read
data by detecting the polarity of
the particles.
Sector
When formatting the hard drive, the
computer divides the disk into radial
sections called sectors.
Track
Circular and concentric paths
the read/write heads follow
when reading information from
the disk.
11. How a Mechanical Mouse
Works
As the ball rotates it turns the two
rollers mounted perpendicular to one
another. One roller corresponds to
vertical movements of the mouse,
another corresponds to horizontal
movements.
Two small switches in the front of the
mouse register left and right mouse
clicks.
A perforated wheel and a photoelectric switch
measure the rotations the ball makes as the
mouse is moved, thus moving the cursor on the
screen. The photoelectric switch consists of a
light-emitting diode (emitter) on one side,
and a phototransistor (receiver) on the
other side. The perforated wheel is
sandwiched between the two,
turning the switch off and on
as it rotates.
A third roller is used
not for measurement,
but instead to keep
the ball in place as
the user moves the
mouse.
12. Major Components of a Motherboard
SIMM RAM Bank
Single Inline Memory Module
stores data to be used by the
microprocessor.
ROM BIOS
Basic Input/Output System
stores permanent instructions
that start the computer.
Power Connector
Supplies power to the
motherboard.
16 Bit ISA Slots
Allows expansion of computer
through modem, sound and
video cards.
32 Bit PCI Slots
Allows expansion cards that
can transfer data faster than
ISA slots.
Battery
Provides power
for the system
clock.
Cache RAM
Stores and retrieves information
for the microprocessor at a faster
rate than SIMM RAM so
instructions can be executed faster.
Microprocessor
Single integrated circuit that
executes the majority
of the instructions
to process
data.
13. External Modem
Plugs into computer externally
Internal Modem
Fits inside computer
Modems can send data from one computer to another using telephone lines.
Modems are used in almost every aspect of work. Businesses use them to transfer
files, data, and money. They are also used for teleconferencing, which allows people
in various locations to communicate over vast distances; these are sometimes called
virtual meetings. Schools use them to provide access to the Internet.
Modems
14. Microsoft Office is one of the most popular
software suites available for business,
educational, and personal computer use.
• Word processor
• Database program
• Spreadsheet
• Presentation software
• Information management
Software suites are full-
featured versions of several
different programs
packaged together.
Software Suites
15. •Artificial Intelligence - Computer
brains that become self-teaching and
self-thinking.
•Cloning - Duplication of cells and
DNA to create an exact copy of an
organic being.
•Cybernetics - The union of the
organic and inorganic.
•Virtual reality - All-encompassing
computerized microworlds for
business and entertainment.
What does the Future Hold for
Computers and Society?
16. Detecting Computer Viruses
What is a computer virus?
A computer virus is a relatively small program that
can vary in its destructiveness from being a minor
nuisance, to a major disaster. Three common methods
of access include:
1) Disk in drive A: with virus program
2) Downloaded files through BBS/Internet
3) Via LAN server
What types of viruses are there?
• Logic bombs wait until a specific action is taken.
• Time bombs activate on a certain date.
• Trojan horses appear to be legitimate programs but
when opened, damage software codes.
• Worms burrow through and between networks to
change or overwrite data.
2
3
1
17. Data Encryption
Modern encryption techniques use complex mathematical algorithms that scramble and lock confidential data
contained in e-mail messages and binary files. There are two fundamental approaches to encryption: public-
key encryption and conventional encryption. Both require user passwords. Conventional encryption uses two
identical or symmetrical keys that both the sender and the recipient have. Public-key encryption uses two
different keys to encrypt and decrypt files. The advantage is that only one key needs to be kept secure and that
key doesn’t need to be shared.
Public-Key Encryption (Asymmetrical)
Conventional Encryption (Symmetrical)
File encrypted with public key Locked file sent to recipient File decrypted with secure key
File encrypted Locked file sent to recipient File decrypted with identical key
18. The Future of Computing:
Parallel Processing
Deep Blue
Pathfinder and Sojourner on Mars
Parallel processing subdivides the processing workload with multiple processors, enabling a
computer to complete a task in shorter time. Examples of parallel processing computers include
Cray supercomputers, IBM’s chess master Deep Blue, and NASA’s Mars Pathfinder.
Cray supercomputer
19. Society and the Future of Computing:
Telecommuting
Since the word was first coined over
20 years ago, telecommuting has
grown to be an increasingly viable
alternative work structure that not
only increases productivity but
lowers operating costs and worker
turnover as well.
Advantages
• Greater employee retention and lower turnover
• Reduces traffic congestion and taxes for road
repair and new highway construction
• Reduces absenteeism
• Reduces pollution
Disadvantages
• Requires greater discipline and self-motivation
• Greater number of distractions at home
• Reduced on-site interaction with clients
and coworkers
