| From: | Alexander G. M. Smith |
| Date: | 17 Sep 2000 at 21:46:32 |
| Subject: | Re: AMIOPEN: Compressed archive formats and Installers |
Martin Baute <solar@baud.de> wrote on Fri, 15 Sep 2000 21:06:48 +0100:
>> No. I think CD Writer allowed you to save a whole new file
>> and would look like it came from the CD. The point here was
>> you only had to save the diff, and the filesystem woud undiff
>> the source and delta files - much less disk space is used.
>> Perhaps I'm wrong about CD Writer.
>
> Semi-correct. You could both create new files, and replace
> existing ones. It�s correct however that full files were
> saved, not diffs.
I had a look at GNU HURD and it seems to do everything we were
discussing. It has "store" things which can be layered (have
multiple children, each responsible for a portion of the file)
and otherwise connected together. I'm not sure if "stores"
are between the disk partition level and file systems or
between file systems and the user. Guess it could be used for
both. There are even some functions for building a kind of
file name describing a collection of "stores"
(store_children_name) possibly so you can reconstruct them
from a user provided file name.
The list of standard "stores" includes patch-like functionality
and could easily do the merge file system or CD Writer. See
http://www.gnu.org/software/hurd/doc/hurd_8.html#SEC86
for a list of them - things like a gzip based store, ones
which interleave (for RAID style disk striping), concatenating
ones, multi-volume files, etc. Lots of good ideas there.
- Alex
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