fish wrote: > On Fri, Jun 06, 2003 at 07:57:02PM +0200, Thomas Leske wrote: > > One could also solve the two problems without containers: > > 1) completeness: > > Make FEC work for sets of small files. The regular files are > > just inserted normally. The zip archiv is only generated on the side of > > the inserter or reader for creating respectively using the > > error correcting blocks but the archiv is not stored on freenet. > > I should point out, that if your container is large enough to FEC (that's > around a meg), then your container is too fucking big - in ideal conditions, > (i.e. not freenet), a 56k modem (which are very common, despite what some of > the broadband elite think) will take around 5-10 minutes to fetch your data.
But this is a shortcoming of the current FEC implementation that was designed to protect large splitfiles. If you choose a smaller block size in the fec algorithm, it could be used on smaller files as well. There is a quite flexible tool that could do the job independent of fproxy: http://parchive.sourceforge.net/ But an in-freenet solution would be much more elegant, because the site can be browsed via fproxy and you can reinsert missing chunks. Of course you would not base the FEC Encoding on the zip archive format, but extend the current FEC meta data to allow different sizes for each chunk and an arbitrary block size. The chunks are concatenated to a large file that is split into blocks in order to determine the correcting blocks. It may also be useful, to allow zero padding after a chunk up to the next block boundery. If the block size is quite small, you would combine the correcting blocks to a number of larger chunks. The second version of parchive allows correcting chunks of increasing sizes of 2^n. Thus you have to download just as much error correction information as you need.
> And that[s of course on the low end of the FEC scale. Files this large > should not be allowed to be containered.
Note that there is no container in my proposal that everyone has to download. One can also just browse a site in the usual and unreliable way. Only if you what to fetch the whole site or you really need a certain missing file you use the FEC feature (and combine the chunks to a container in your client).
Thomas
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