Transcript HOW A COMPUTER PROCESSES DATA

HOW A
COMPUTER
PROCESSES
DATA
• What is hardware?
• Hardware is the electric, electronic and
mechanical equipment that makes up a
computer
• What is software?
• Software is the series of instructions that tells
the hardware how to perform tasks
• What is input and input devices?
• Any data or instructions which you enter into the
computer
• What is output and output devices?
• Output is data that has been processed into
information
What is a computer?
An electronic machine
 operates under the control of
instructions stored in its own memory
 can accept data
 manipulates the data according to
specified rules
 produces results and
 stores the results for future use
• Who is a computer user?
• A user is someone who communicates
with a computer or uses the information it
generates.
• What is data?
Data is a collection of unprocessed facts,
figures and symbols
• What is information? Information is data
that is organized, meaningful and useful
How a computer process data?
• Processing is the thinking that the computer
does - the calculations, comparisons, and
decisions.
• People also process data. What you see and
hear and touch and feel is input. Then you
connect this new input with what you already
know, look for how it all fits together, and come
up with a reaction, your output. "That stove is
hot. I'll move my hand now!" .
• The kind of "thinking" that
computers do is very different
from what people do.
• Machines have to think the hard
way
• Complex procedures must be
broken down into VERY simple
steps
Processing components
Computers processes data
• The CPU, or Central Processing
Unit, is the part of the computer
where work gets done. In most
computers, there is one processing
chip.
ALU
• ALU stands for Arithmetic/Logic Unit
• This is the part that executes the computer's commands.
A command must be either a basic arithmetic operation:
+ - * /
or one of the logical comparisons: >< =not=
• Everything has to be broken down into these few
operations.
• The ALU can only do one thing at a time but can work
very very fast.
Main Memory
• Main Memory stores the commands that the
CPU executes and the results.
• This is where the computer stores the data
and commands that are currently being used.
• When the computer is turned off, all data in
Main Memory vanishes.
• A data storage method of this type is called
volatile since the data "evaporates."
• The CPU can fetch one piece of data in one
machine cycle.
The Machine Cycle
Control Unit
This is the part of the computer that controls the Machine Cycle.
It takes numerous cycles to do even a simple addition of two numbers.
Fetch -
get an instruction from Main Memory
Decode -
translate it into computer commands
Execute - actually process the command
Store -
write the result to Main Memory
OPERATING SYSTEM
• Operating System
• This is the instructions that the computer
uses to tell itself how it "operates". It's the
answer to "Who am I and what can I do?"
• Some common operating systems are
DOS, various versions of Windows, OS/2,
UNIX, LINUX, System 7. These all behave
in very different ways and have different
hardware requirements. So they won't all
run on all machines.
Application
• Applications
• These are the various programs that are
currently running on the computer.
• By taking turns with the Machine Cycle, modern
computers can have several different programs
running at once. This is called multi-tasking.
• Each open application has to have some data
stored in Main Memory, even if the application is
on rest break and is just sitting there.
Input/Output
• Input/Output Storage
• When you enter new data, the
keystrokes must be stored until the
computer can do something with the
new data.
• When you want data printed out or
displayed, it must be stored
somewhere handy first.
Working Storage
• Working Storage The numbers and characters
that are the intermediate results of computer
operations must be stored until the final values
are calculated. These values "in progress" are
kept in temporary locations.
• For example, if the computer is adding up the
numbers 3, 5, and 6, it would first add 3 to 5
which yields a value of 8. The 8 is stored in
working storage. Then the 8 and 6 are added
and the new value 14 is stored. The value of 14
is now available to be displayed on the screen or
to be printed or to be used in another
calculation.
Unused storage
• Unused Storage
• One hopes that there is always
some storage space that is not in
use.
• If space runs out in Main Memory,
the computer will crash, that is,
stop working.