to answer my own question, for the sake of others......
1)swap space... YES, knoppix can use spare writeable memory on hard disks as swap space, which can be deleted when not needed.
2)YES, you can install knoppix to a hard disk vie 2 possible methods...
i) use a program call knoppix-installer. the downside, is that it needs to decompress the cd from 700 megs to 2.5 gigs.... which is stupid cos knoppix is meant to be small
ii) my method....
use fdisk to greate a 710 meg partitonon a hard disk.. then
cat /path/to/knoppix.iso > /dev/700_meg_hard-drive_partiton
however you will need a boot floppy... which is on the knoppix cdrom.
mount -o loop /path/to/knoppix.iso /mnt/cdrom
cat /mnt/cdrom/knoppix/boot.img > /dev/fd0
the floppy disk is now a boot disk....
restart, insert boot disk, and set bios to boot from floppy.
3)possible to install new software....
YES....
when you get the boot prompt after booting knoppix 'boot:'
type 'knoppix home=/mnt/hda2` (or wherever you have writeable hard disk space)
the hard disk space must be set to writeable by all, or owned by user 'knoppix' with chown and chmod commands, before booting knoppix with that home dir setting.
now, you have a home directory (all changes made to user knoppix like backgrounds and themes will remain after reboot)
anyway, now programs can be installed to home directory... for example..
http://quakeforge.sourceforge.net
download from cvs (the normal release has a bug which means u cant load a saved game) then
./bootstrap
configure --prefix=/mnt/home_directory_you_chose
make
make install
works perfect. (you will need to copy some files from the orional id1 quake cd)
so to summerise...
yes, yes, yes