First off all:
HI there. I’m one of the new writers on this fab page of wisdom.
I will mostly be talking gibberish as Skulbru is, but I will try to write most about CCNA.
Before we get started, be advised, I’m currently taking the CCNA course part time.
What that means is that the info published should not be taken as the definite fact.
I’m writing what I have come to think is the correct fact. But I may just be wrong ;0)
Back to the topic!
Binary and Hex is not that different from our number system.
You have been taught since kindergarten that we are counting in 10’s.
0,1,2,3,4,5,6,7,8,9,10 and then
11,12,13,14,15,16-20 and so on.
The binary system is counting in 2’s and the hex is using 16’s.
While this may seem confusing, it’s not. Let’s look at the numbers in a different way:
In the first picture we can see all 3 “language’s” .
Note that Hex start has the letters A-F where we normally have 10-15.
To get higher numbers you simply add more letters/numbers to the line..
Binary is a little bit more confusing for starters. There we only have 1’s and 0’s.
What we have to remember is that it’s no different than regular decimal language.
We still count the places that are marked on or off.
Have a look at the next picture and maybe you will get a better idea of what I’m trying to explain.
If you look closely you will see that Binary is really easy, it’s just 1′s and 0′s that mark a position.
And you start counting from left to right.
Meaning that the binary value of 1111 1111, really means that all positions are on.
To be specific: 128+64+32+16+8+4+2+1, and that equals the decimal value of 255.
Also notice that the values multiply from the 1 value.
What’s worth to remembering is that if you are to write in binary you have to start off from the left.
For example you can’t write the decimal number of 78 as anything else than 1001 1100.
Why do we need these ways of counting numbers you may ask?
Well either one is fine. But the human mind has difficulties with counting all the 111110000111.
The computers don’t. For them it’s the perfect way, because the computer can then use voltage on or off, or high and low, to communicate with others.
Just like we used the Morse code to communicate back in the days of early radio.
The hex on the other hand is relatively easy to understand and could just as easy been our proffered math language to use today.
Computers today use binary on the most basic level of communication, and then moves over to hex.
Hex is based, as I said before, on 16. This means that it’s just another way of counting the on and of positions.
We use this in the OSI model. It’s a guideline as to how computers and programs are to communicate. The 1 layer is called the physical layer and only operates with 1’s and 0’s.
The second layer is the Data-Link layer and talks with hex.
I will get more into these subjects later on.
But when you read hex values you will see that when it comes to computers they will mostly start as 0x. This is Cisco’s way of telling us that this is a hex value.
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Your binarycode for the number-two in your list is wrong
ah crap. yeah i will change the formula as soon as possible.
There its done ive corrected the error.
that’s what happens when you write late at nigth…
/cheer