BSD and System V

[cybo]

I'm relatively new to UNIX and Linux. Recently I got a book on UNIX: UNIX for the Impatient. Really good one. It had a chapter on BSD and System V, tried to explain differences between them but I still couldn't figure it out. Does anyone know what is the difference between BSD and System V and which one is Ubuntu?

Thnx

[ibutho]

Linux is neither SysV nor BSD although it has some elements from both of them. Wikipedia provides detailed info about both of them (search for system v and bsd).