Messages in this thread | | | Date | Thu, 26 Aug 2004 17:53:51 +0100 | From | Jamie Lokier <> | Subject | Re: silent semantic changes with reiser4 |
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Rik van Riel wrote: > And if an unaware application reads the compound file > and then writes it out again, does the filesystem > interpret the contents and create the other streams ?
Yes, exactly that. The streams are created on demand of course, and by userspace helpers when that's appropriate which I suspect it almost always is.
> Unless I overlook something (please tell me what), the > scheme just proposed requires filesystems to look at > the content of files that is being written out, in > order to make the streams work.
Yes. Hence the idea of coherent views between two files: writing to one affects the content of the other, although the calcalation is only done on demand (or when the fs wants to migrate the representation -- for example, creating the flat container prior to deleting the regeneratable pieces in order to save space).
I haven't seen anything from Namesys that says they'll do that. I have the impression the streams are just generated in memory on the fly, not stored on disk with a cacheing policy, but that's just an impression. (We've all seen the Namesys white papers, they're not _that_ revealing). :)
I'm just pointing out how to do it _right_. I think it will turn out like this eventually, either next year or some time over the next decade after some iterations. Inevitable. Mark my words, etc. :)
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