Ramdisk and partial remastering in Knoppix 7

[utu]

.
First, a historic note:

In post #1 I called some attention to Klaus K's recent murmurings about using
'ramdisk' as an alternative to some of the more recent re-mastering schemes that
use lots of resources and time.
You may be interested to know this is not something new or even new to Knoppix.
Just take a look at:
http://www.oreillynet.com/sysadmin/b...s_wow_jus.html

Now, for something closer to home:

In posts elsewhere on this forum I have touted a little scheme of I think-of as
'partial backups'. I try to keep track of the tweaks I use and where they go, so
I can collect these in a file update*.tar.gz. I then use the cheatcode note about
how to get this file overlaid on KNOPPIX-DATA and become a part of
knoppix-data.img. I've used this all through Knoppix 6 to back-up my LiveUSB when
I ruin my knoppix-data.img by some inadvertent mistake. Maybe a little clumsy, but
it serves the purpose. my tweaks in update*.tar.gz amount to about 50 Mb which
I store on /mnt-system/ in-between uses.

It turns out, I can read this 50 Mb update*.tar.gz into the Knoppix 7 ramdisk and
produce an equivalent 30 Mb KNOPPIX1. I have to do some juggling with reboots
and using the knoppix noimage cheatcode to accomplish this, but it works.
There are two hidden bonuses in this approach. First, you needn't be very
fastidious about noting your tweaks and where they go. Ramdisk does this for you.
It only retains the directories, and contents thereof it needs to record differences
from an initial compressed image. Second, after all the manipulations you may
once again re-install a persistence file to record retain any additional
changes you might decide to investigate on a more tentative basis than the
ramdisk approach.

You don't need a second system to accomplish all this. I bootstrapped my 8 Gb
Knoppix 7.0.2 LiveUSB from an update*.tar.gz state to a ramdisk-modified version
with persistence using only two special commands and the cheatcode 'knoppix noimage'.
A second system would be a good idea as a backup, but this is just to let you
know it's possible to do without.

The two commands that are crucial are: To transfer update*.tar.gz to /ramdisk/;

sudo tar -xzf /mnt-system/update*.tar.gz - C /ramdisk

and, To create the file KNOPPIX1 you will need to complete this task:

sudo mkisofs -R -U home etc KNOPPIX-DATA var (or whatever the ramdisk dirs were) \
        | create_compressed_fs  -B 131072 -m - - >/tmp/KNOPPIX1

I'll work out a turn-by-turn list eventually,

but the first step is rebooting with knoppix noimage to bring in the ramdisk;
next read update*.tar.gz into ramdisk;
next get rid of your original knoppix-data.img and KNOPPIX-DATA;
next make your directory list and issue the second command to produce KNOPPIX1;
next move KNOPPIX1 into the directory that has KNOPPIX and formerly held
KNOPPIX-DATA as well; and
last, but not least, reboot and re-establish persistence, when prompted to do so.

I may have thrown in a few re-boots here and there along the way to see how
things were going. I'll have to make some notes. But the preceeding gives you
the broad outline.

I think there is a sequel to this that Klaus K has defined which describes
how to combine compressed images, but I've not progressed that far yet.

I'm interested to hear the experiences of others with Knoppix 7's ramdisk.