Originally Posted by anant tailor
[SIZE="5"]how many types of partitions and file systems are in linux?[/SIZE]
Partitions are not a linux thing. There are many systems to define partitions on a physical disk. In the world of personal computers the most widely used model is the MBR model, which defines up to four primary partitions. One of these primary partitions might be of a special type, name it "extended partition". Primary partitions and extended partitions are mostly the same thing, with the particularity that extended partitions can hold inside additional "logical drives". This is a way to overcome the hard-limit of only four primary partitions that the MBR has.
Another famous model is EFI, which overcomes many of the limitations of MBR, however it's not widely supported yet.
You can read about both (EFI and MBR) in the wikipedia, there are very good articles there if you need more info.
About filesystems, well, you could write a few books about that actually. The so-called standard Linux fs, nowadays and for a long long time now, if ext2/3 (and now ext4, though it's not as tested as ext2/3).
But linux support natively many other fs's. The concrete number of fs's that your kernel will support depends entirely on the options you enabled when compiling it and the kernel version you are using. Most distros also patch the kernel to get support for additional fs's (for example, reiser4), and there are also fs's that are supported via userland modules written for FUSE (sshfs, ntfs-3g, etc.) or VHBA (cdemu). So, it's not trivial matter.