Transcript How Computers Work

CIT 1100
The evolution of the computer:
 The first known device used to assist with
mathematical calculation was the Abacus
developed around 3000 BC
 In 1617, John Napier created a mechanical
calculator; referred to as Napier ’s bones it was a
crude slide rule
 In 1672, Blaise Pascal developed the first
mechanical adding machine, capable of addition
only
 In 1822, Charles Babbage created the Difference
Engine which is touted to be the first general
purpose computing machine
Replica of Charles Babbage’s Difference Engine
Based on the decimal
number system and was
powered by cranking a
handle
The London Science Museum
The first devices were designed to
assist with mathematical computations
 All were mechanical, large, slow and
cumbersome
 Capable of precise error free
calculations
 Based on decimal numbering system
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Personal computers (PCs)
Desktop computers
Notebook (laptop) computers
Tablet PCs
Handheld computers
PDA (personal digital assistant)
MP3 players
Mainframe computers
Supercomputers
Special Purpose Devices
 Every automobile built since 1995
 Airplanes
 Boats
 Mall lighting systems
 Home security alarms
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Music
Visual Art
The Graphic Arts industry has changed
dramatically through computers as well
Extremely powerful Supercomputers are used to
create modern 3-D models used in animation,
games and military simulations
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Banking
◦ On-Line banks
◦ Credit Cards
◦ ATM Machines
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Retail Sales
◦ Book Stores are being replaced by on-line sales
 Amazon Kindle
 Digital Print Media
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Internet Commerce increased from $500 million
in 1996 to over $6 billion in 2000
Any individual with a Web Site can compete with
a multinational corporation
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Games
Today, many of us regularly play computer
games on the Internet that enable us to talk
run, and explore with people all over the world
at the same time
Interactive game play can incorporate players
from all over the world
Computing devices have transformed modern
life in ways too numerous to list
Computers are basically machines, made up of different components  A modern computer consists of three major
components:
1. Hardware
◦
Physical thing that you can touch or hold in your hand
Operating system
2.
◦
Controls the hardware and enables users to interact
with the computer (interface)
Applications
3.
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Programs that allow you to do specialized tasks
Computers work through three stages:
1.
Input
2. Processing
3.
Output
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The user initiates the action by doing
something:
◦ Clicking the mouse
◦ Typing on the key board
◦ Touching the touch screen
This is input
Components inside the system take over at
that point The operating system instructs the hardware
how to handle your request
At the heart of every computer is a central
processing unit (CPU), usually a single, thin
wafer of silicon and millions of tiny transistors
The CPU handles the majority of the processing
tasks and is the "brain" of the computer
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Once the computer has processed the
request, it shows you the result by changing
what you see on the monitor or playing a
sound through the speakers
This is output
There are nine steps that apply to most computers and
computing devices when you want to get something
done
1.
2.
3.
4.
5.
6.
7.
8.
9.
Power up
Processing parts prepare for action
User provides input
Input commands are processed
CPU send output information to your output devices
Output devices show you the results
Repeat steps 3-6 until complete
Save your work
Power down the computer
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Computers have a piece of hardware called a
power supply that plugs into some kind of
power source, like an AC outlet on a wall
Once power is applied the power supply
delivers voltage to system components to
initialize them
The power supply connecting to devices
The Power Supply is vital to the operation of
many components inside the system  If there is a problem it can effect the system in
many ways
◦ If the power supply is completely dead obviously the
entire system would not operate
◦ If the required voltage levels expected from the
power supply were incorrect it can effect
components differently
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A good rule to follow is to suspect the easy
things first, if the system is dead, is it plugged
in?
There are five main parts that handle processing:
CPU, Motherboard, RAM, Hard drive, and Operating
System - Here's how they are initialized:
 The hard drive is a storage device, holding the
operating system and programs
 The CPU can't work with the software directly from
the hard drive because the hard drive is too slow
 The CPU needs to load the operating system into
special high speed memory called random access
memory (RAM) to be able to work with the OS
 All software used by the computer has to load into
RAM before it can be used
To
speed the
up the
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to
the
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Random
Access Memory RAM is added
needed
by the CPU
the
CPU
Load the
application
WORD
Here it Comes
Load the
application
WORD
High Speed RAM
delivers data to the CPU
Speed
Limit
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Here it
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Speed
Limit
30
Once the program is in RAM, the CPU sends the update to
the video card and monitor displaying the output
At some point in the process, especially when
creating an original item, you'll want to save your
changes
 You can do this at the end, when you're satisfied
with your work, or when you need to stop for a
while and want to pick up later where you left off
 Up to this point all your work is maintained in
RAM which is Volatile, so if power is lost you so
is your data
 Saving your work copies the data back onto the
hard drive which is nonvolatile
Call this
letter to mom
Save the work and call
it letter to mom
Copy data back from
RAM onto Hard Drive
Nearly every modern computing device has
some kind of sleep mode, a way for the device
to shut almost everything down automatically.
 In Windows 7, for example, go to the Start
button and hover over the arrow next to Shut
Down and select Sleep.
 This means you don't have to turn off the
computer or device every time you walk away
for a few minutes