Course two Module 2 converting binary numbers to hexi decimal numbers.
Hexadecimal again is a base 16 numbering.
System numbers and letters are used to represent zero through 15.
Zero through nine are just the digits zero through nine, 10 through 15.
The numeric values of 10 through 15 are represented as the letters A to F.
Hexadecimal is used as an easier to understand representation of binary data.
What that means is our tools are not going to show us a binary representation
of the data because it would just be too much to look at.
That's why we use hexdecimal because it is more compact and
much easier to interpret and view.
But remember, data is not stored on disk in hex.
It is stored in binary and again, that's either a wonder.
Zero, a positive or negative charge on the disk itself.
Your forensic tools will perform the conversion to hex for
you to convert by an area to hex.
The first thing we want to do is we want to split the bite into two nibbles and
we talked about bites and nipples in our last section.
A bite being an eight bit value and a nibble being Half a bite,
a four bit value.
So we would go ahead and
in this case in our example we have the hexdecimal number five f.
So we're going to split that, the left and right nipple.
The left nipple would be the five and the right nibble would be the f.
going to take our columns and we're going to re
weight them Instead of having 1,248,
16 32 64 and 1 28.
We're going to have columns numbered 1248 And 1248.
We'll start with the F.
We know the numeric value of F is 15.
So we're going to go ahead and put a one in the eight column,
one in the four column and a one in the two columns and a one.
The one call the numeric
value of five is five.
So we would have a zero in the eight column,
a one in the four column 80 in the to column and a one in the ones column.
And that is how we would convert our hex a decibel number to decimate.
We would now have to go ahead and re wait the columns for
each nibble back to their original numbers,
which again would be 1,2,4,8,
16,32, 64, 128.
Here we can see our columns are related.
We have R one R two or four or eight or 16 32 60 four and 1 28.
We would again go through the same process we
did before adding all these numbers together,
I would add the 64 to 16 plus eight plus four plus two plus
1 which would convert our hexidecimal value back into a decimal Value of 95.
Of note is the least significant bit is the bit furthest to the right and
that would be the ones column in this case and the most significant bit is always
going to be the bit Further to the left and in this case that is the 1/28 column.
That will become more important as we move through the course.
So you can see we have the number 95.
We split our two nibbles.
We would drop our values down into our re rated re weighted columns 84-1.
We would have all ones there that would give us a total of 15 And
15 in Hexi decimal is F.
And then we would look to our left nipple and we have our columns
of 1248 again we would add our column values that have ones
in them together which would be the four And the one and we would get a five.
So hexi decimal five f.
is decimal 95.
Now we're going to take a quick look at a decimal value of two bites.
And another way to convert it.
We talked about decimal hex to decimal being A Base
16 Numbering System With a column of 016,
256 and then 4096.
And how this works is the column furthest to the right is 16 to the zero power.
Next would be 16 to the one Which would be 16,
16 to the to which would be 256 and
16 to 3rd Which would be 4,096.
Now we would take our bites and
put them in the columns to A and three B.
Three B.
Being the columns on the left to A.
Being the columns to the right.
We would multiply three times 4000
96 Come up with 12,288.
Next we have our hex value of B which we know is 11.
So we would multiply 11 times 256 and
we would get the number of 2816.
Next we Would go to our 16's column 16 to the first
power where we have a value of two for the two first two and to a.
We would multiply 16 times two and come up with 32.
Now we would go to our column furthest to the right which would be our value of A.
And we know A in hexidecimal decimal number of 10 so
16 to the zero power is zero.
So we would just have 10.
Now we would take all of our numbers and add them together.
So that is 12 288 plus 2816.
For a three A to B for our three B.
Excuse me then we would add 32 plus 10 For our two a.
And we would have a total of 15 146.
So the two byte value, which would be a word,
two bites of hexi decimal three B to A is 15,100 and 46.
In your path folder there are worksheets with
hexdecimal two decimal values that you can convert and
also binary values that you can convert from decimal to binary.
There's also an answer sheet in there with the examples so you can do some practice
and make sure you've grasped the concept before you move on to the next course.
In our next block, we're going to talk about negative numbers, how we get
a negative number and that's going to involve something called a signed integer.