[Bootcd-user] A Different RAM Disk Approach / RAMTYPE

[Mark Clarkson]

So tmpfs is a souped up ramfs, and a ramdisk is something completely
different. The only thing gained by using tmpfs is limit checking since
we have no swap. (sounds useful to me)

Vlado Plaga wrote:

> -  My current working computer (PPC with a 2.6.6 kernel) does not want
>     to mount a tmpfs disk, but mounts ramfs. It says:
> 
>     mount: wrong fs type, bad option, bad superblock on tmpfs,
>            or too many mounted file systems

Scary! - This would make

    RAMTYPE="<tmpfs|ramfs|ramdisk|auto>"

to allow you to drop back to ramfs on the 2.6.6 kernel on PPC.

So for the 'auto' case:

  If kernel >= 2.4 then
    RAMTYPE=tmpfs if CONFIG_TMPFS found
    RAMTYPE=ramfs if CONFIG_RAMFS found
    otherwise RAMTYPE=ramdisk
  else
    RAMTYPE=ramfs if CONFIG_RAMFS found
    otherwise RAMTYPE=ramdisk
  endIf

I suppose we would also need

   TMPFS_SIZE=<size in mb|auto>

where auto would be half the memory(?).

To start I would probably keep /ram1 and /ram2 and only symlink
from /ram[1|2] to the tmpfs/ramfs directory. I think this would
'waste' around 4mb in inodes but better than breaking everything.
Hopefully bootcd2disk would not need modifying by doing it this
way.

Also I would only store /tmp, /home, /root and /var on the tmpfs
mount leaving /etc and /dev where they are on /ram1.

Sound okay?

Cheers
Mark.