Transcript power point

A
computer is an electronic device that
receives data (input), processes data, stores
data, and produces a result (output).
 It performs only three operations
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Arithmetic operations (adding, subtracting,
dividing, and multiplying.)
Logical comparison values (equal to, greater
than)
Storage and retrieval operations
 Big
deal..? Why and how do you use
computers and which kinds do you use?
Digital versus Analog
A
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digital device uses discrete data.
Discrete data is distinct or separate.
Ex: Numbers or digits.
 Most
computers today are digital. Their
circuits have only two possible states, such
as “Off” and “On” or “0” and “1”.
Digital versus Analog
An analog device operates on
continuously varying data.
Continuously varying data has an
infinite number of possible states.
Digital versus Analog
A
digital thermometer will give a specific
numerical reading when used to measure
someone’s body temperature.
 An old fashioned mercury thermometer’s
reading of someone’s body temperature
could be interpreted differently by different
users.
Type
Size
Power
Purpose
Supercomputers
Largest
Fastest processing
speeds compared to
other computers
•Cost can be several million
dollars
•For corporations with lots
of data to be processed
Mainframe
computers
Large
Less powerful than
supercomputers but
large compared to
personal computers
•Can cost hundreds of
thousands of dollars
•Performs centralized
processing tasks for many
users
Minicomputers
Larger than
microcomputers
but smaller than
mainframe
computers
Same as
microcomputers
•Used for companies with
many users and large
amounts of data and can
run on any computer
hardware
Microcomputers and
notebook computers
Fits on a desktop
Not meant for large
amount of data
•Writing papers, tracking
finances, playing games,
connecting to the Internet.
PDA’s, Cell phones, calculators, interactive books, digital cameras, game systems are accepted
as they make everyday tasks easier to accomplish.
Role: The CPU also called microprocessor, or
brain of the computer, contains millions of
switches and pathways to help the computer
make decisions. The switches control the flow
of electricity as it travels across the pathways.
Computer programs are special instructions
written to tell the computer which switches to
turn on or off.
 Speed: deciding factor on which computer to
purchase. The system clock is an electronic
pulse used to synchronize the processing and
determines the speed of the processor, measured
in megahertz. The higher MHz the faster the
computer.

Computers only understand machine language,
or binary, which is ones and zeros.
 Through the pathways and by turning switches
on and off the CPU processes ones and zeros
 When electricity is present it represents a one.
The absence of electricity represents a zero.
 Coding Systems such as American Standard Code
for Information Interchange (ASCII) determines
which combination of zeros and ones represents
the letter A or the number 1.
 Each one or zero is a bit, and eight bits or
combinations of ones and zeros represents a
byte.

 RAM
– (random access memory) often
referred to as main memory is the data,
information, and program instructions
temporarily stored on a RAM chip. If there is
a power loss this is the information lost. The
amount of Ram can help increase how fast
the computer processes data.
 ROM – (read only memory) stores specific
instructions needed for computer operations.
The computer can read from a ROM chip but
cannon write or store data on this chip.
 Secondary
storage devices are used when you
want to store a file or information
permanently
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Computer’s hard disk drive
Floppy disk
CD-RW/DVD-RW/BD Rewriter
Thumb drive
A
network connects one computer to other
computers and peripheral devices
 Allows computers to share:
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Data – special group projects, databases, etc.
Hardware – printers or scanners
Software – instead of purchasing programs for
each individual computer, a site license can be
purchased for the number of users and it is less
expensive
Files – collaborative, allows users to work
together
A
server is a computer connected to a
network that distributes and stores resources
for other network users.
 With proper licensing, many network users
can use the same applications and data files
simultaneously and share other resources,
such as storage space or a printer.
 Local
Area Network (LAN) –
a network located in a limited area.
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LANs are found in most businesses.
Many campuses use LANs.
A
network interface card (NIC) –
a key hardware component.
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Connects a workstation to the network.
A circuit board that sends data between the
workstation and the network.
 Wide
Area Network (WAN) –
a network that covers a large geographical
area. TENET is a classic example.
 All types of networks require special
networking hardware and networking
software to allow different computers to
communicate with each other.
 The
Internet - largest of all networks.
 Communication standards called protocols
allow for global exchange of information.
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Transmission Control Protocol (TCP)
Internet Protocol (IP)
 Intranets
are LANs or WANs that use these
communication standards or TCP/IP.
 Special hardware (modem) and software
(browser) are required.
Speed versus Cost
 How
fast are you able to access and save
data on the hard drive?
 How fast will application software open?
 How quickly will software respond to
commands?
 How quickly will your printer produce a
document?
Capacity versus Cost
 How
many applications can you store on a
hard disk drive?
 How much data can you store on a secondary
storage device?
 How many applications can be opened
simultaneously?