> 
> Here is the typical RAM-disk root approach:  (SunOS, some SysV)
> 
> (1) Kernel is configured to use RAM-disk ("rd") as root device
> (2) The "rd" init routine stops the world as if in kernel debug
>     and reads in a RAM-disk image from some predetermined place.
> 	(typically it prompts: "insert boot diskette 2")
> (3) The mountroot call proceeds on the open block device with the
>     file system image copied in by the open call.
> 
> This is quite easy to do...
> 
> Gordon
>

The problem is that you need a working kernel to mount a ram disk,
since a user process allocates memory for it.

A better solution would be to creat yet another filesystem, possibly
called smfs (simple memory fs), that wouldn't have all the fancy
things mfs has (like using swap), but at init time it could grab
the memory needed for smfs root (How good is it on a 4M machine?).

Also the fs code could be much simpler, for install we don't need stuff
like symlinks, long names or even rwx bits.

The boot code will still have to copy files or a special floppy image
to this memory, or maybe this could be done in the kernel as part of the
fs init routine? The later one needs a separate install kernel, but seems
simpler.


And yes, I know that it's a new someone-should-do-it type idea :-).

szabolcs

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