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what should i do if i want to have got TCP in my OS. i know that i shoul use first ARP, later IP and then my lovely TCP but what before ARP??

Before anything you're going to need a network driver for your ethernet card... that would be my first step.

--Jeff

where can i find infromations about it??

Hello,
the following six PDF documents discribe the functionning of NICs of different brands and different types. One of them even contains some assembler source code for a driver. The files are 3 megs. I hope they will help.
3c90xb.pdf
3c90xc.pdf
dp8390details.pdf
dp8390overview.pdf
ne2000.pdf
writingdriversforthedp8390.pdf

thank you very much!!! i'm sure that it help me
ok, what i should do now (if we think i have got driver for my ethernet card)

Hello,
you could probably begin studying some network protocols and network programming.
You may find some useful informations in these sites.
http://www.ecst.csuchico.edu/~beej/guide/net/
http://www.rfc-editor.org/rfcsearch.html

did you mean that i now must make sockets in my OS??

Implement the exact API from for example BSD sockets or Winsock ... no, that should not be necessary unless you want.
Implement something that follows a similiar concept - in the end you'll end up doing this no matter what you do, as this is what TCP/IP basically is.