Check X memory usage
$ xrestop
Check system memory usage
$ top
just about anything found on the net
$ dd if=/dev/cdrom0 of=output.iso
Change cdrom0 with devices you need to make image from, and output.iso with image file result.
To mount it, use
$ mount -o loop output.iso /path/to/mntdir
$screen
Print a list of pid.tty.host of screen identification
$screen -ls
Reattach/resume screen session
$screen -r pid.tty.host
Detach a screen
ctrl-a d