How to mount ramdisk upon startup

[tckotb]

K, but can you tell me how I can have the data moved into the ramdisk at boot, and taken out on shutdown?

[Lisiano]

Okay, to copy on the files on boot. You could set cron to auto copy the files on boot.
Open a terminal and type the following

export EDITOR=nano
crontab -e

Now add this line

@reboot cp -rpf /home/user/temp /dev/shm

(Correct me if I'm wrong but I think user crontabs work even when the user is not logged in)
(@reboot works on boot as well, not just reboots)
Now press Ctrl+O -> Enter -> Ctrl+X

For the shutdown, this is a bit tricky and risky.
As a AI known to some people would say:
"Federal regulations require me to inform you that this next step is... looking pretty dangerous"
So. This step is dangerous, might eat your cat, break your flowerpot, take all your money, point fingers at you and laugh.
To minimize the risk we will edit a system file that is responsible for unattended upgrades.
Type this

gksudo gedit /etc/rc0.d/S10unattended-upgrades

Or if you really liked nano

sudo nano /etc/rc0.d/S10unattended-upgrades

Add this line

cp -rpf /dev/shm/temp /home/user/

right after the comments end (The ones with #) and the PATH, NAME and DESC lines. So it should look like this (Might be different since I'm on 11.04)

#! /bin/sh
#
### BEGIN INIT INFO
# Required-Start:
# Required-Stop:
# Provides:          unattended-upgrade-shutdown-check
# Default-Start:     
# Default-Stop:      0 6
# Short-Description: Check if unattended upgrades are being applied
# Description:       Check if unattended upgrades are being applied
#                    and wait for them to finish
### END INIT INFO


PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin
NAME=unattended-upgrades
DESC=unattended-upgrades

cp -rpf /dev/shm/temp /home/user/

set -e

case "$1" in
  start|stop)
        echo -n "Checking for running $DESC: "
        python /usr/share/unattended-upgrades/unattended-upgrade-shutdown
        ;;
  restart|force-reload)
        # nothing
        ;;
  *)
    N=/etc/init.d/$NAME
    echo "Usage: $N {start|stop|restart|force-reload}" >&2
    exit 1
    ;;
esac

exit 0 

Don't edit anything else. Save the file and now manually copy the temp folder to /dev/shm (Not contents, the folder)

[Enigmapond]

You would need to write a small copy/move script and place it in /etc/init.d/ directory and chmod +x to make it executable. I'm not sure where the reverse script would go for shutdown. I'm only guessing as that directory is the boot...

[Lisiano]

Oh. Didn't notice about a init script, just add this at the beginning of the script instead of crontab

cp -rpf /home/user/temp /dev/shm

Also you can just add this on the stop rule in the init script instead of editing /etc/rc0.d/S10unattended-upgrades

cp -rpf /dev/shm/temp /home/user/