The 'Save-file' and 'Save-folder' explained...
This is one of Puppy's 'secret weapons'.....and the reason why Puppy is so easy to recover, in the event of major 'melt-down'. Both of these contain a full Linux file-system inside them.
The 'save-file' was the first to be developed, and was essentially in the squash file-system format. At boot-time, Puppy, having located the save-file, will decompress the contents of it into RAM, layering it into the union file-system in such a way that it appears, to the user, to be one contiguous, normal Linux file-system. The save-file then remains in the 'dev-save_tmp' folder during your session; at shut down, any incremental changes from your session are written back to the save-file, and the whole thing is re-compressed as part of the shut-down procedure, and saved back to its original location, overwriting the previous one in the process.
The only limitation of the save-file is that it is 'fixed' in size. Utilities exist within Puppy for enlarging it, when it's getting full; it can't, however, be reduced in size. This was the reason for the development of the 'save-folder'; it will expand and/or contract in size like any normal directory, up to the maximum permitted by the partition in which it is installed to.
As long as you keep regular back-up copies of your save-file/folder (literally a copy & paste procedure - no need for special back-up programs), if Pup should throw an irrecoverable 'wobbly', it's a simple matter to replace the save-file/folder from outside of Puppy (again, 'delete', followed by copy/paste), then re-boot Pup. It'll be running in the condition it was in at the time the previous save-file/folder was backed-up. A half-hour job at most.
And, so long as the recommended format of ext3 is used, it's almost foolproof, since this contains the 'lost & found' directory for use with the 'e2fsck' utility, which can be used to confirm the save-file/folder's integrity. Ext2 is supposedly the best format to be used with flash-installed Pups.....but it has a tendency to 'corrupt' rather easily. This has been discovered through years of experience by various Puppy Forum members.
It is, if you like, the Puppy version of Windows' 'System Restore'.....except it's guaranteed 100% reliable, unlike the latter's well-known tendency to 'balk' at the critical moment..!
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This is an over-simplified explanation, I'll own; but it explains the basic points well enough for the layman. A more detailed explanation about the workings of the union layer file-system can be found here, from the PuppyMaster himself, Barry Kauler:-
http://barryk.org/puppylinux/develop...uppyworks.html
Mike.
