Baslinux mailing list

[sindi keesan <keesan AT sdf.lonestar.org>]

On Wed, 12 Jan 2005 3aoo-cvfd AT dea.spamcon.org wrote:

> sindi keesan wrote:
> > > Yes, the loop version of BL3 has a small ramdisk
> > > (to anchor the loop file).  IIRC it is less than 100kb.
> >
> > My partner wants to know more about this ramdisk.
>
> In order to use a loop file as the root filesystem,
> you must first mount the partition where the loop
> file resides.  fs.img (the BL3 loop file) resides
> in the baslin directory on a DOS partition.  So
> you need to mount the DOS partition and then mount
> /baslin/fs.img.  This is done by a tiny filesystem
> running in a ramdisk.
>
> Have a look at boot.bat
> --------------------------------------------------
> loadlin zimage root=/dev/loop0 initrd=initfs.gz rw
> --------------------------------------------------
> It tells the kernel to unzip initfs.gz to a ramdisk

Where does it say to use a ramdisk?  In bl2 root=/dev/ram0
The ramdisk is mounted on /initrd ?

> and run it.  initfs is a small filesystem (containing
> a shell and a few necessary utilities/devices).  It
> automatically runs a script to mount the loop file
> at /dev/loop0.  The kernel then uses it as the root
> filesystem (root=/dev/loop0).

/initrd/linuxrc = 16K   bin =609 bytes
> Once the kernel is running on /dev/loop, the shell/
> devices/utilities in initfs are redundant.  However,
> it is not possible to un-mount the ramdisk.  The
> ramdisk still contains the mountpoint for the DOS
> partition. You can't kill the ramdisk without killing
> access to fs.img

Would it save a tiny bit of memory to delete linuxrc and everything esle 
besides /DOS from ramdisk? I think you said linux could use memory from 
empty parts of a ramdisk.

> > can he look at it?
>
> Yes, the ramdisk is still mounted (at /initrd).  You
> will find the executables in /initrd/bin and the devices
> in /initrd/dev.  The script for mounting /dev/loop is
> /initrd/linuxrc.
>
> Cheers,
> Steven
>
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keesan AT sdf.lonestar.org
SDF Public Access UNIX System - http://sdf.lonestar.org