WEBVTT

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Course two Module 2 converting binary
numbers to hexi decimal numbers.

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Hexadecimal again is a base 16 numbering.

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System numbers and letters are used
to represent zero through 15.

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Zero through nine are just the digits
zero through nine, 10 through 15.

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The numeric values of 10 through 15
are represented as the letters A to F.

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Hexadecimal is used as an easier to
understand representation of binary data.

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What that means is our tools are not
going to show us a binary representation

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of the data because it would
just be too much to look at.

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That's why we use hexdecimal
because it is more compact and

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much easier to interpret and view.

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But remember,
data is not stored on disk in hex.

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It is stored in binary and
again, that's either a wonder.

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Zero, a positive or
negative charge on the disk itself.

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Your forensic tools will perform
the conversion to hex for

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you to convert by an area to hex.

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The first thing we want to do is we want
to split the bite into two nibbles and

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we talked about bites and
nipples in our last section.

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A bite being an eight bit value and
a nibble being Half a bite,

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a four bit value.

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So we would go ahead and

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in this case in our example we
have the hexdecimal number five f.

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So we're going to split that,
the left and right nipple.

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The left nipple would be the five and
the right nibble would be the f.

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going to take our columns and
we're going to re

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weight them Instead of having 1,248,

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16 32 64 and 1 28.

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We're going to have columns
numbered 1248 And 1248.

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We'll start with the F.

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We know the numeric value of F is 15.

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So we're going to go ahead and
put a one in the eight column,

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one in the four column and
a one in the two columns and a one.

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The one call the numeric

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value of five is five.

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So we would have a zero
in the eight column,

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a one in the four column 80 in the to
column and a one in the ones column.

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And that is how we would convert our
hex a decibel number to decimate.

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We would now have to go ahead and
re wait the columns for

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each nibble back to
their original numbers,

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which again would be 1,2,4,8,

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16,32, 64, 128.

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Here we can see our columns are related.

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We have R one R two or four or
eight or 16 32 60 four and 1 28.

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We would again go through
the same process we

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did before adding all
these numbers together,

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I would add the 64 to 16 plus
eight plus four plus two plus

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1 which would convert our hexidecimal
value back into a decimal Value of 95.

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Of note is the least significant bit
is the bit furthest to the right and

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that would be the ones column in this case
and the most significant bit is always

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going to be the bit Further to the left
and in this case that is the 1/28 column.

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That will become more important
as we move through the course.

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So you can see we have the number 95.

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We split our two nibbles.

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We would drop our values down into our
re rated re weighted columns 84-1.

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We would have all ones there that
would give us a total of 15 And

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15 in Hexi decimal is F.

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And then we would look to our left
nipple and we have our columns

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of 1248 again we would add our
column values that have ones

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in them together which would be the four
And the one and we would get a five.

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So hexi decimal five f.

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is decimal 95.

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Now we're going to take a quick look
at a decimal value of two bites.

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And another way to convert it.

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We talked about decimal hex
to decimal being A Base

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16 Numbering System With a column of 016,

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256 and then 4096.

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And how this works is the column furthest
to the right is 16 to the zero power.

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Next would be 16 to
the one Which would be 16,

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16 to the to which would be 256 and

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16 to 3rd Which would be 4,096.

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Now we would take our bites and

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put them in the columns to A and three B.

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Three B.

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Being the columns on the left to A.

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Being the columns to the right.

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We would multiply three times 4000

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96 Come up with 12,288.

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Next we have our hex value
of B which we know is 11.

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So we would multiply 11 times 256 and

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we would get the number of 2816.

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Next we Would go to our
16's column 16 to the first

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power where we have a value of two for
the two first two and to a.

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We would multiply 16 times two and
come up with 32.

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Now we would go to our column furthest to
the right which would be our value of A.

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And we know A in hexidecimal
decimal number of 10 so

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16 to the zero power is zero.

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So we would just have 10.

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Now we would take all of our numbers and
add them together.

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So that is 12 288 plus 2816.

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For a three A to B for our three B.

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Excuse me then we would add 32 plus 10 For
our two a.

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And we would have a total of 15 146.

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So the two byte value,
which would be a word,

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two bites of hexi decimal
three B to A is 15,100 and 46.

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In your path folder there
are worksheets with

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hexdecimal two decimal values
that you can convert and

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also binary values that you can
convert from decimal to binary.

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There's also an answer sheet in there with
the examples so you can do some practice

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and make sure you've grasped the concept
before you move on to the next course.

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In our next block, we're going to talk
about negative numbers, how we get

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a negative number and that's going to
involve something called a signed integer.