You can have only up to 4 fdisk primary partitions by design and Solaris 10 doesn't allows to create extended partitions (OpenSolaris recently removed that limitation). You can have up to 16 slices inside the Solaris partition but I suppose there is no more room to set one in your setup.
What I would suggest would be to create an additional primary partition with the remaining 50 GB and use it as a ZFS pool. You will have then the possibility to create a virtually unlimited number of file-systems in the pool.
jilliagre and incredible..
really sorry for not replying to your posts. My monitor is not working now and it is under service. Thanks a lot for your replies. I will get back soon with more doubtss.... thank u ........