A
computer
is an electronic device that
receives data (input), processes data,
stores data, and produces a result
(output).
It performs only three operations
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
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.
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
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
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
Secondary storage devices are used
when you want to store a file or
information permanently
Computer’s hard disk drive
Floppy disk
CD-ROM
A
network
connects one computer to
other computers and peripheral devices
Allows computers to share:
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
