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COMPUTING :D :D :D :D






















































UNIT ONE


Page 2

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Contents

Components of a Computer System 3
The Systems Life Cycle 4
Categories of Software 7
User Interfaces 8
Bits, Bytes and Number Systems 9
Validation and Verification 13
Computer Hardware 14
Data Transmission 19
Networks 21
Legal Framework 24






























































2

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Components
of
a
Computer
System





Hardware-The
physical
components
of
a
computer



Software-All
of
the

programs
that
run
on
the

computer
system
for

example
the
OS
and

application
software

Systems
software-
Controls
the

hardware...includes
the

OS


















































and
utility
software

Application
packages-
Allow
the
user
to

perform
everyday
tasks



Input
devices-Allow
data…

Page 4

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The
Systems
Life
Cycle



A
continuous
process
used
to
ensure
the
successful
development
of
a

system.

-Problem
definition:

Forms
the
basis
of
the

requirements
for
the
new

system.
There
must
be
a

problem
with
the

existing
system
for

a
new
one
to
be

developed.

-Feasibility
study:

The
aim
is
to…

Page 5

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·The
test
strategy,
test
plan
and
test
data

·Conversion
Plan
-
how
the
new
system
is
to
be
implemented

Documentation
including
systems
and
operations
documentation

Prototyping-building
a
working
model
of
a
system
in
order
to

evaluate
it,
test
it,
or
have
it
approved
before
the
final
product
is

built.

-Implementation:…

Page 6

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Developers
often
have
to
rework
earlier
stages
in
light
of
experience

gained
as
the
development
progresses.
A
project
milestone

terminates
each
stage,
and
the
end
user
has
very
little
say
in
the

development
process.
















































































6

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Categories
of
Software



Generic
Applications
Packages-Software
packages
that
have
a
range

of
everyday
functions
depending
on
their
purpose,
for
example
Word

Processors
and
Database
software.
Businesses
may
use
this
kind
of

software
for
Stock
Control,
Order
Processing
etc.



Utility
Software-"house-keeping"
software.
Designed
to
keep
the

system
running
as
smoothly
as…

Page 8

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· Multi
user-Two
or
more
users
can
communicate
with
a

computer
at
a
time,
accessing
via
a
terminal









User
Interfaces



Command
line-Mainly
used
by
advanced
users,
word
based

commands
are
entered
to
carry
out
tasks.



Menu
driven-Rarely
used
on
computers,
users
navigate
through
a

series
of
menus.



Natural
language-Where
the…

Page 9

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Bits,
Bytes,
and
Number
Systems
<3
<3



Units
of
storage:

·1
bit
-
a
single
1
or
0

·1
nibble
=
4
bits

·1
byte
=
8
bits

·1
Kilobyte
(Kb)
=
1024
bytes
(210)

·1
Megabyte
(Mb)
=
1024
Kb
=
1,048,576
bytes
(220)

·1
Gigabyte
(Gb)
=
1024…

Page 10

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Sign
and
Magnitude-The
first
bit
signifies
a
positive
or
negative
sign

so
negative
numbers
can
be
represented.
1=negative
0=positive

For
example,
the
binary
for
35
is:



+/-
64
32
16
8
4
2
1



0
0
1
0
0
0
1
1





The
binary
for
-35
in
sign
and
magnitude…

Comments

Karolis

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Why is there a huge chicken on the front page?

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