Is it time?

[eerrrr]

Ohh, this is rare. A post form eerrrr in the Tech forum!
Anyway,  I was thinking of having a go at learning something techy. I've been thinking of it for a while. And I was wondering if I could have you help? I was thinking about learning things about Hex first, but I have no idea how hard these things get. Which would be simple one to start with?
Oh yeah, I also have no idea where to start. Are there any free websites that could teach me the basics of a language?
Thanks.

[The Skillster]

ok errr, heres the basics of the hexadecimal numerical language  
0,1,2,3,4,5,6,7,8,9,a,b,c,d,e,f,10,11...1a..20.
see my point? its like normal numbers but ur adding A-F on as XTRA numbers so its 0-F instead of 0-9.
i thinks thats enuff for one lesson?

[eerrrr]

       
Heh, only kidden'. So it's instead of having loads of numbers it can add a letter from A-F to each number? Ok.
Thanks Skillster!

[Alhexx]

eerrrr: It's good to hear that u want to join us. So I'm going to help u where I can.

Well, I guess teaching the basics through a board is going to be a bit work...  

But well, Skillster has posted the basic basic   . If u understand that, what he posted, it's a good beginning. I'm postin' some values that you will have often to do with: (I store them as Bytes, means a 2 digit hexadecimal number)

Hex         Dec
00          Well, 0
0F          16
10          17
64          100
FF          255

Well, that's how the HEX-editors show the byte values. You should use a hex editor that can convert hex values into decimals and the other way. (I use Hexworks for this)(Ok, I mostly use Ultraedit, but it can't convert 'em)

 - Alhexx

[eerrrr]

Um, right. Is there a connection between the Hex and the Decimal value? Or can it only be converted using a program? Ok, thanks Alhexx.

[Sir Canealot]

*looks at topic*
And these numbers and letters mean something eventurly then?

[eerrrr]

I was just wondering. What can I do wth hex? So far with hex editors I'm guessing you get the address on the left, the hex numbers in the middle and the binary output on the right. But what can I do with hex? Like, is it used to write files and stuff cos I often hear The SaiNt mentioning looking through the FF7PC hex files or something. I was just wondering what the point of Hex is.

EDIT:
Wooo I've got a better view now. I just started playnig around with a hex-editor I downloaded (Hex Workshop) and opened some files. In an HTML file I understand that each two hex digits makes a text character. So would be 3C48 544D 4C3E? Heh, I havent memorized each charecter to each hex byte yet! I just copy and pasted that. Hmm, its starting to make more sense...

[This message has been edited by eerrrr (edited August 10, 2001).]

[The SaiNt]

I hope my explaination is clear.  

The hex format is basically just a way of representing data on the PC.
The hex format is a number format that has a base of 16.

If you don't understand what a base of 16 is, well then read on.

code:

 1
+1
--
 2
--

[/quote]
This kind of addition is used in the base 10 system. Take notice of this:-

code:

 1
+9
--
10
--

[/quote]
What has happened here? Since the biggest digit is 9, when I add 1 to it, the number "spills" over to the next possible placing making the total 10.

So, now let's try changing things a little and moving to base 2, which means the largest number is 1.

code:

 1
+1
--
10
--

[/quote]
Eh? That wasn't what they taught me in primary school? I thought 1 + 1 is 2?
Actually this works the same way the 9 + 1 example worked for base 10. For base 10 the largest digit was 9 so the "spill-over" only occurs at when you add 1 or more to 9. For base 2 however, the largest digit is 1 so the "spill-over" happens immediately.
Understood? If yes, then let's continue on.

Now what happens if I decide to use base 16?
The maximum digit would be 15 wouldn't it? Now you come across a problem, how can you tell if 215 really means
215 or does it mean 21 as the first digit and 5 as the second?
That's why the hex system was created.
In the hex system, the numbers go like this:-
0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F
Using this system a single character can represent 16 different numbers
1 represents 1
2 represents 2
3 represents 3
.
.
.
A represents 10
B represents 11
.
.
.
F represents 15
So, in a hex editor, you will find that hex numbers are grouped in 2 digits at a time or maybe more(depends on your configuration). Each hex character can represent 16 different numbers so 2 hex character can represent 256 different numbers(16x16). So, it is directly possible to convert hex numbers into decimal(base 10) numbers.

Now, when you look into a file using a hex editor like Hex workshop, the address's(offsets) appear on the far left. The hex numbers appear in the center and the ASCII representation appear on the right. You don't really have memorize what each hex number represents. The ASCII format is only certain "mask" applied onto the hex numbers. Earlier, I told you that the hex number F can represent 15 right? Using the same method, the hex number 3C should give you 60 decimal. If I were to apply an ASCII mask, the hex number 3C would represent "<"
See where I'm getting? ASCII is only one method of using hex numbers to represent the data. There are probably millions of methods of using hex numbers to represent things. Hence, we take such a long time to figure out FF7's file formats.

[Alhexx]

eerrrr: Trying around is one of the best ways to learn - learning by doing.

SaiNt: Interesting lesson - but you're right.

- Alhexx

- edit -
Oopps, just have to correct sth. from my first post:
Hex   Dec
0F  15
10  16

Thanx to you, SaiNt!

[This message has been edited by Alhexx (edited August 10, 2001).]

[Threesixty]

You lost me on the 3C equals 60.

OH wait....
**************************
3C
if C=12
same as
3(12)

The first number means 3x16 and the bracket number is to be added

....if it was algerbra it would be {3y+12=x ; y=16} or {3(16)+12=x}

so I caculate the first number by:
3 x (16 base) = 48

48(12)
then add the non bracket number by the bracket number
48+12 = 60
************************

But FF = 255?

*****************
calculations:
F=15
15 x (base 16) = 240
240+15=255
****************

so what is 256?

I guess zero is considered a number.....

16x16=256, but FF=255 (nothing should be higher than F in your Base 16, thingy)

...only way that you can say that base 16 has 256 values in it, is to say that zero is a value itself......no wonder this is so confusing!

[Clone5]

You don't have to stick with just one byte.  You can express 255 as 00 FF instead of just FF.  When you add one to and "F", it would go to 10.  Same would happen with FF.  When FF was added to 01 you would get 01 00, which is 256.

[This message has been edited by Clone5 (edited August 11, 2001).]

[Sukaeto]

It's not really confusing, we're just used to the decimal system (using ten base numbers), hex is just a way of counting using sixteen base numbers.  The reason why hex is used in computing is because it is MUCH simpler to convert between hex and binary than it is to convert between decimal and binary.

Each hex base number has a unique 4 bit value in binary.  Since there are only 16 possible combinations for a 4 bit binary segment, once you know which 4 bit segment equals which hex base number, converting between the two is extremely simple.

0000 = 0
0001 = 1
0010 = 2
0011 = 3
0100 = 4
0101 = 5
0110 = 6
0111 = 7
1000 = 8
1001 = 9
1010 = A
1011 = B
1100 = C
1101 = D
1110 = E
1111 = F

Knowing that, you can take any hex number and convert it to binary:

E.g FAC7 = 1111101011000111

Converting from hex to binary is equally as easy:

E.g. 1001011010011011 can be split into 4 bit segments: 1001 0110 1001 1011 and then translated into hex by looking at the chart above: 969B

If a binary number DOESN'T split into all even 4 bit sections, such as 11 0101 1100, just add two as many zeros in front of the first segment to make it equal 4 bits: 0011 0101 1100, making that number 35C in hex.

[Alhexx]

all: Holy ****!

eerrrr: Ehm, still alive? Or commited suicide   ?

- Alhexx

[eerrrr]

Wow! Thanks a lot! I was waiting around here for ages yesturday for replies, then I went on the scheduled Legacy chat. JP and Dag were on and they taught me loads of stuff! In about two hours they taught me that binary to hex table TiadaghtonDude wrote, stuff about bits and a load of other stuff. But thanks everyone for posting these, I'm still a bit confused about the Base 16 thing and stuff but I'll read through it again. So is that like the basics of hex? Or is that around everything? I have no idea how learning hex will be useful to me but it seems that all of you know it so I guess I should too.
So what should I do now? Learn more about hex or start learning a language? How did you guys learn your languages? Did you get lessons or learn stuff for free on the internet? I'd like to learn stuff for free off the internet, then when I get to college I should be more than ready to do well in a computing course.

Alhexx: I couldnt find Hexworks, so I ended up downloading Hex Workshop, and I downloaded UltrEdit I think, just haven't tried it yet. And yes, I just about survived all that.
Thanks everyone!            

EDIT:
Why am I editing this? It's been quite a while since I posted it. Anyway, I decided to start learning VB. I found a pretty good site called   http://www.vbweb.co.uk" TARGET=_blank>VBWeb   which has a good beginner's tutorial. But I dont have a program. I've got the Office 2000 VB prog but thats supposed to be crap. Does anyone know where I can download Visual Basic for free? Or am I gonna have to go buy it?

EDIT:
Oh dear. I found something which looks like Visual Basic on Morpheus, but it's 70MB. Hmm, maybe I can get it off my dad's friend cheap.

[This message has been edited by eerrrr (edited August 11, 2001).]

[This message has been edited by eerrrr (edited August 11, 2001).]