first of all thank you all of you for helping me..:) i got this correct, libzypp is backend of yast,which is writen in c++. Yast core is the collection of the lower level libraries and YCP (Yast Control Programming) language is the API of yast. It is writen in these 3 language or 1 of them is the main language and the other 2 are just languages for bindings? Yast module=firewall,software management etc? (according to "man yast" firewall=module) libyui is a part of yast core?which is his actual work and how it is working in combination with Qt frameworks? zypper and yast share some code or they are two differend frontends for libzypp? Also seeing the bugzilla i saw that there is no much work for qt programing for yast.Is that correct? looking at yast's svn repo i found out some *.cc,i know that they are related to c++,but can u explain it more to me? sorry for my big reply and thank you for your time :) -- To unsubscribe, e-mail: yast-devel+unsubscribe@opensuse.org For additional commands, e-mail: yast-devel+help@opensuse.org