How is a ramdisk different from an initrd. Can we choose either of them as our root file system? If not, what are the typical usages?
A ramdisk is exactly what the name says - a disk in RAM. Essentially a chunk of memory is presented as if it were a disk. A ramdisk can be partitioned / formatted (for any file system) and mounted, just as a normal disk can be. Yes, a ramdisk can be used as thye root file system. In fact, ramdisk is very commonly used to host the root filesystem in embedded systems (Typically, compressed ramdisk images are permanently stored in flash memory, and upon boot up, they are uncompresses in RAM and mounted to /). initrd (Initial ramdisk) is a USAGE of ramdisk, in which the kernel modules / files needed by the kernel at a very early booting stage can be made available. An initrd is mounted as a temporary root file system while booting. This initrd contains the minimal drivers (eg SCSI) that are needed to locate the actual root filesystem on the disk. Hence initrd = a usage of ramdisk. Regards, Rajat -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
