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Computer Basics
Introduction to computer basics
Key Topics
Electrical Pulses
One’s and Zero’s
Size definitions
Reasons For Conversions
Reasons For Conversions
Working In Base 10
Working with base 2
Converting to Binary Example1
Converting to Binary Example 2
Hexadecimal Numbers
Table of conversion
Converting to a Hexadecimal Number
Converting Numbers Example 2
ASCII
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-
Computer
processing is designed around binary
and
we should have some familiarity with binary if we will be working
computers.
-
The
process for the conversion of decimal
numbers
to binary
and
hexadecimal
is
a straightforward and practical.
-
Electrical
pulses
-
One’s
and zero’s
-
Size
Definition
-
Reasons
for Conversion
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Since computers use electrical
pulses to communicate then a pulse = yes = 1 and no pulse =No = 0.
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Therefore computers work by
using ones and zeros which is in reality using the binary
numbering system.
-
Each one or zero defines a bit
of data.
-
8 bits of data is equivalent to
one byte of data.
-
10101101 = 1byte of data.
-
Information
is usually defined in bytes.
-
The
quantities of space within the different devices
such
as the hard drive
or
the memory
are
measured in proportions of bytes.
-
8
bits = 1 byte
-
1024
bytes = 1KB (Kilobyte)
-
1024
KB = 1MB (Megabyte)
-
1024
MG = 1GB (Gigabyte)
-
1024
GB
=
1 TB (Terabyte)
-
1024
TB = 1 EB (Exobytes)
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Although
binary
defines
how computers work, humans work in decimal
and
find it difficult to understand binary.
-
Hexadecimal
numbers are used because
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When we deal with numbers
larger then 8 bits in modern computers that are 32/64 bits it becomes
difficult to keep a tab on all the ones and zero’s for human beings.
-
They provide an easy conversion
route to binary
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You will need to be able
convert
decimal
numbers into binary
and hexadecimal
and vise versa as part of your
job.
-
The situations where conversion
is useful include: -
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Defining the IRQ
, DMA
and IO address
.
-
When dealing with TCP
/IP
addresses
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When dealing with jumper
setting and SCSI
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We
are familiar with base 10
-
Within
base 10 the largest single digit number we can have is 9
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To
calculate the value of a number
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Is
equivalent to: - (5x1000)+(3x100)+(2x10)+(1x8) = 5328
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10011000
is equivalent to: - (1x128) +(0x64) +(0x32)+(1x16)
+(1x8)+(0x4)+(0x2)+(0x1)
= 128+16+8=152 in decimal
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ASCII
stands for American Standards Code
for Information
Interchange
pronounced as asskee.
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All
characters on the keyboard
have
been defined with individual ASCII binary
byte
equivalents.
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The
character A=65 dec = 01000001 bin =41 hex
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The
character a=97 dec = 01100001 bin =61 hex
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The
character? =63 dec = 00111111 bin =3F hex
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ASCII is a universal standard
that means that all systems
recognize ASCII from PC’s to Unix
systems to Apple systems
Questions
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Convert the decimal
number 57 to binary
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00011100
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01010101
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00111001
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00111101
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Convert the decimal
number 85 to binary
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00011000
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01110101
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10101010
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01010101
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00110101
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Convert the binary
number 11010101 to decimal
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23
-
56
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123
-
213
-
234
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Convert the binary
number 01110101 to decimal
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223
-
156
-
117
-
113
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234
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Convert the binary
number 11010101 to decimal
-
23
-
56
-
123
-
213
-
234
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Convert the binary
number 11010101 to hexadecimal
-
AB
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5C
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D5
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DF
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F2
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Convert the binary
number 11010111 to hexadecimal
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AB
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FC
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D5
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D7
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FF
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DA
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Convert the binary
number 11111111 to hexadecimal
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AB
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5C
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D5
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DF
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FF
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Convert the binary
number 11111101 to hexadecimal
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AB
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5C
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FD
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DF
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F2
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Convert the Decimal number 145 to
hexadecimal
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223
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45
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91
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78
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200
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Convert the Decimal number 192 to
hexadecimal
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D2
-
45
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91
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C0
-
DF
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Convert the Decimal number 255 to
hexadecimal
-
BD
-
45
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91
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CD
-
FF
Answers to questions
1.
D
2.
D
3.
D
4.
C
5.
D
6.
C
7.
D
8.
E
9.
C
10.
C
11.
D
12.
E
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