[CentOS] Clarification on Linux CD or DVD Writing

Dear All,
    Currently working setup is CentOS4.4 Linux
    I tried to google-out, but i can't able to findout

    I need some clarification about CD writer support

   1. How can i findout inserted disc is CD or DVD from command line
   2. How can i findout inserted disc is empty from command line
   3. How can i findout inserted disc size (like 700 MB or 4.7 GB) from
      command line
   4. Which writer i can use

    Please can any help me
    Thanks in Advance.

Regards
-S.Balaji