(resolved) Re: Ramdisk on fixed disk: how?

B. James Phillippe (bryan@terran.org)
Thu, 26 Feb 1998 16:12:25 -0800 (PST)


Hello,

A few days ago, I sent this message to linux-kernel..

> I'm working with a bootable Linux floppy that uses a ramdisk to
> mount as root. I'd like to be able to use the same technique on a system
> that's booting of a fixed IDE disk. However, all my attempts have failed.
> Rather than mount the ramdisk, the kernel just mounts the hard drive
> partition. Is there a special setup procedure I need to follow, or is
> ramdisk-off-harddisk not supported?

I received several replies of the nature "this isn't a kernel issue" and
"read the Bootdisk-HOWTO", and a few replies of genuine help offers. I
would like to clarify that this is indeed a kernel issue, and that I have
discovered how to resolve it. The function rd_doload, in the file
drivers/block/rd.c contains this line:

if (MAJOR(ROOT_DEV) != FLOPPY_MAJOR) return;

which effectively makes booting the ramdisk as the root filesystem (without
initrd) impossible. I have removed this line and am now able to boot my
ramdisk boot image off of a fixed disk without any change other than
reinstalling LILO. I am aware of the use of initrd, and that it could also
provide the functionality I'm looking for, however, in this case I would
prefer not to use it in order to save space.

My question now is, what is the reasoning behind limiting the ramdisk to
the floppy device? My workaround seems to work properly for what I am
doing, is there any reason not to make this change in the mainstream
kernel?

thanks,
-bp

--
B. James Phillippe <bryan@terran.org>
Linux Software Engineer, WGT Inc.
http://w3.terran.org/~bryan

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