Multicore internal ZIP

[hlloyge]

Well, I would like to suggest, if it is possible, to add multicore compression for internal zip archiver, for making really quick backups... is that possible?

[ghisler(Author)]

This would be possible when packing many small files, because each file is compressed separately (no solid archives), but not when packing 1 large file. The ZIP compression doesn't look like it could be parallelized well, because the compression results of later bytes depend on the results of previous bytes.

[hlloyge]

That would be an advantage, too, for making quick backups of folders with documents. Can you implement that, please?

[ghisler(Author)]

Sorry, that's not something which could be done over night, it's very complex to get it right. In the worst case, it would be even slower, because the disk operations to read all the various files take a considerable amount (and reading from multiple files at the same time is a very bad idea).

[hlloyge]

I wouldn't be asking if it hasn't been done in 7zip's zip compression - it takes multiple cores and compresses files; when dealing with one big file, it does employ just one core; but when dealing with folder with a lot of smaller files, it is considerably faster. Hard drives are not so slow as ten years ago, and they can handle reading four files at the same time.

[MVV]

hlloyge, you may use 7-Zip's compressor for such cases if you know that it is faster.

[hlloyge]

Well, I am, but if there is a space for improvement, why not improve on internal zip compression?

[MVV]

I would improve something more important BTW.

[hlloyge]

I would improve something more important BTW. Very Happy

You are welcome to do that, but compression is important to ME