I am a stranger here ,where can i get the operation for free.thank you!
We get asked this queston approximately 9,000 times daily. If you do not wish to do a search, then I'll have to tell again how, "os purity" arguments notwithstanding, UNIX is an operating system design, not a blue box emblazoned "UNIX" that you go out and buy.
There are many OSes built to this design with greater and lesser degrees of compliance to the standard. You have your pick of BSD, Linux, Solaris, IRIX, QNX, AIX, SCO, HP-UX, Apple OSX...
Of these I'd reccomend Linux because it's free and compatible with nearly all common consumer machines(read, intel x86), but you'll find no shortage of other reccomendations here.
u can go to ubuntu.com and order for ubuntu linux(not unix!!!) and it will be shipped to you free of cost. you can also download it from that site. you can also download many otehr .iso files for other linux's for free....depends on whther you have unlimited net access at ur disposition 