How to partition a disk for installing Ubuntu?
I bought a new laptop with following configuration: 640gb hard disk and 4gb RAM with pre installed windows 7. right now the hard disk partition is dynamic in nature. now I want to multi boot my system with windows 7 and ubuntu,may be A third OS in future. so kindly please suggest me the appropriate partition scheme along with the file system which can work efficiently. roughly I want 3 primary and 1 extended partitions.I am not able to decide about the sizes of each.I need to share my data with both the operating systems.kindly mention in detail about the partition scheme ? thanks in advance