[wellylug] looking for a lazy cd-backup solution

[Ewen McNeill]

In message <1062484254.23307.51.camel at damon.asianreflection.com>, Damon Lynch writes:
>On Tue, 2003-09-02 at 18:23, Ilia Pavlenko wrote:
>> no, I want readable cdr's :) not a cdr containing one huge 640mb tgz file
>> (which will require a heaps of room if I need to pull out 1 file only !)
>
>Are you aware of the very real limitations in filename / directory
>length on a CD?  

That's true of an ISO9660 file system (8.3 names, with version numbers
a la VMS).  But both rockridge (Unix) and Joliet (Microsoft) support an
"overlay" which allow for longer file names, and (AFAIK) deeper
directories -- a suitably compiled Linux kernel will support both
transparently (I use it all the time).  (Just build your file system
with mkhybrid -r -J/mkisofs -r -J and you'll get both overlays for
maximal portability.)

Of course you can put anything else you like onto the CD providing
you're just going to work with it on a Unix-like system (ie, one that
doesn't have preconceived expectations of what CDs contain).  You could,
for example, put an ext2 file system on there.  Or xfs.  Or reiserfs.
(You would, of course, have to build the whole file system first, and
then copy it onto the CD -- none of those file systems are suitably
structured for worm-like writing.  A log-based file system would
probably be okay for packet-writing to the CD as you went.)

One of the great things about unixes is that they're very orthagonal
with their use of media -- it's blocks all the way down.

Finally two semi-serious suggestion: cramfs.  A read-only compressed
file system.  As used by Knoppix and Gentoo and various others to fit
lots of stuff onto a single CD/smaller CD.

And secondly compressed ISO9600 images.  With the right (experimental
IIRC) option enabled in the kernel I believe Linux will read them
transparently (I've not tried myself).

Ewen