@sharmin, please do not compare linux with windows. both of are different kernel and different platform now a days.
and about your question no# 2, In modern times in Unix-like systems, especially Linux, directory structure is defined by the Filesystem Hierarchy Standard. that's why linux does not need drives.-- Regards, Saeed Ahmed Rajshahi, Bangladesh Blog: http://saeed05.wordpress.com -- Follow Me Linkedin <http://www.linkedin.com/in/sas05>Twitter<http://twitter.com/saeed05> -- Ubuntu Bangladesh | http://ubuntu-bd.org ubuntu-bd@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bd
