Uncompressing initrd ??

[Onkar <onkar.n.m@xxxxxxxxx>]

Hi all, 
             I want to see the contents of the initrd image. In that direction  It would be nice to know how grub uncompresses the intitrd image ?? Please give me some pointers as to how do I see how grub uncompresses the initrd .. In fact what is initrd image and is it compresses using cpio utility ??


Thanks & regards,
Onkar Mahajan