Initrd is a initial ram disk for loading a temporary file system into memory in the boot process of the Linux kernel.
This process happen before mounting root filesystem.
For a beginner its very hard to understand but i try to simplify.
To mount the root filesystem the OS must understand the underlying hardware structure
IDE/SATA,SCSI ,SAN DISK.
filesystem architecture such as LVM, RAID
So if this is not understand properly in boot process ,the boot will fail.
Linux guys come up with idea of detecting all this by means of process which is nothing but initrd process .
In this process all the necessary drivers needed to complete the prerequisites to mount root filesystem is done.
Hope you understand.
Last edited by pinga123; 05-07-2012 at 12:16 AM.