cd-based distro idea
 

it's simple: typical partitions become tracks. /etc is a small track. /boot is the first track. /usr is a few tracks, to ease updating... because this is a cd-rw based distro, that boots and updates its compressed 'partitions' back onto its boot disc, making a 700MB compressed harddisk-less portable distro. does it exist? if not, can it be done!?!? think 'multisession', 'packet writing', etc... come on talk to me

yes, there are a few like them around, can't remember the names offhand though

http://plug.twuug.org/articles/cddistro.html

well there's 14 from google...

huh, i didn't find anything like it mentioned here or at LWN's distro list...

another good link, though none of them mention re-writing those live FS's on the fly as in: cache the FS, compress, cdrecord to overwrite the new exact same fs on exact same track at original sectors on disc. same track size, reburn as needed. now it's a cd-distro that updates itself, can save things you downloaded, etc. without having to burn the whole disc again...

i know the downsides begin with limited updates before the CDRW starts to go bad, and in order to recompress filesystems you need a handful of ram... there's no swap either. if you have enough ram you could remount the whole cd on a ramdrive and burn a fresh CDRW in the burner you booted from.

one could also begin with a 2-cd distro: 1 cd-r for static data, one cd-rw for updates... but then you need 2 drives at once and at least one of them has to rewrite. not as portable then.

um, i heard about a cd distro, Devil-Linux that uses a floppy for writability. and the eLSD version makes it *bootable* without the floppy. but i want a self-contained cdrw that carries selectively-erasing self-burning software. no floppies, no harddisks, no ZIPdisks, nothing writeable except the CD*RW* it booted from.
it's not just any cd distro, nothing i've heard of yet and i have looked, was i unclear in the first post? if so, please forgive

are we on the same page now? <no rudeness intended>

I haven't seen anything like that around, and actually I doubt if anyone has actually done that. Mainly because there are way to many limitations to actually make it usefull.

Just some more points you might want to think about:
How often is the data supposed to be re-written to the cd? Every time you update a single thing? This would take ages having to wait for the burn to complete each time and shortens the life of the cdrw everytime. Only once when shutting down? If you do it only when shutting down properly that means you have to keep the total contents in memory and hope you don't get any power downs or crashes in between, because this will mean you lose everything. You would also need a bunch of extra memory which is only temporarily needed, is the extra memory you need really cheaper then a small harddrive?

So although it's probably physically possible you have to ask yourself how usefull is it. And is it worth all the time and effort to create such a distribution. I think most people would come to the conclusion that it isn't worth it and try to go about it in a different way.
Just out of curiosity, what are you planning to use this for?

yes, only when shutting down. and the smaller each track is, the less memory one needs. the other way is unthinkable, you said exactly right. you don't lose everything if a power-down or crash occurs... because you made a very good point there, it seems one would have to leave enough freespace on their disk to burn a track while the original is untouched, that would mean many tracks have to remain untouched...

the idea is to not have a harddrive at all. i can't necessarily open the computers up at college so i can mix-n-match the IDE cables the way i do at home. while a CD distro is perfect for that job, i can't depend on floppies. maybe i'll just go out and splurge on some ZIP disks... though I can't get into the BIOS at those machines and i'm not sure if they already include the ZIP drive in the boot order.... but still, that's only 250MB (their drives)

there's more than one way to do it, maybe i'll just write it all out and see what's worth it. i guess i could adapt a current cd-distro to do this, let's see

sweet! i just found out that cdrecord can blank a single track...

i thought this would be a good idea anyway, bringing it up since i've already heard a few things that need to be dealt with... first, you must have a choice to commit changes at any time, and at shutdown (much like vmware, virtual PC)

also, since it might nuke your disc if a track is in memory being written over the only existing hardcopy, it ought to mirror a track and use the newer one at boot, and blank+rewrite the older one at an update... this means wasted space but safer update. and only for updated tracks! there's also the possibility to only update one track and have the init scripts begin by "patching" your static FS with the recent updates from a single dynamic track

if anyone else has some wisdom regarding compression or cdrw use that I can't find in a howto, i.e. experience to share, speak up!!