Results 1 to 9 of 9

Thread: Bittorrent and solid archives

  1. #1
    Member
    Join Date
    May 2008
    Location
    brazil
    Posts
    163
    Thanks
    0
    Thanked 3 Times in 3 Posts

    Bittorrent and solid archives

    Is it possible to use bittorrent for download only parts of a solid archive?

    Ex: Download 2 files of a solid archive using bittorrent.

  2. #2
    Member Surfer's Avatar
    Join Date
    Mar 2009
    Location
    oren
    Posts
    203
    Thanks
    18
    Thanked 7 Times in 1 Post
    None of existing clients aren't able to do this. And I'm doubt about this function.

  3. #3
    Member
    Join Date
    Jun 2009
    Location
    Kraków, Poland
    Posts
    1,474
    Thanks
    26
    Thanked 121 Times in 95 Posts
    By definition, every part of a solid blocks depends on the previous data in that solid block.

  4. #4
    Member
    Join Date
    May 2008
    Location
    brazil
    Posts
    163
    Thanks
    0
    Thanked 3 Times in 3 Posts
    Quote Originally Posted by Piotr Tarsa View Post
    By definition, every part of a solid blocks depends on the previous data in that solid block.
    Yes. Maybe using non-solid archives like zip it's possible to download only some files.

  5. #5
    Member
    Join Date
    Jun 2009
    Location
    Kraków, Poland
    Posts
    1,474
    Thanks
    26
    Thanked 121 Times in 95 Posts
    When using 7z you have an option to specify solid block size. This way you can achieve higher compression when compressing many small files of same type, but you keep reasonable random access time/ amount of data to be decompressed before extracting any file. IIRC CHM (Microsoft format for help files) files uses LZX with a rather small solid block size and even smaller sliding window.

  6. #6
    Member m^2's Avatar
    Join Date
    Sep 2008
    Location
    Ślůnsk, PL
    Posts
    1,611
    Thanks
    30
    Thanked 65 Times in 47 Posts
    Quote Originally Posted by lunaris View Post
    Yes. Maybe using non-solid archives like zip it's possible to download only some files.
    Theoretically yes. Theoretically with solid archives you could save too by downloading everything in the block before the file that you need - and ignoring everything afterwards.
    Practically no because there's no software capable of doing so.

  7. #7
    Member
    Join Date
    Jun 2009
    Location
    Kraków, Poland
    Posts
    1,474
    Thanks
    26
    Thanked 121 Times in 95 Posts
    Zip format stores descriptors at end of file. I think it's possible to extract only the downloaded parts when there's that information. WinRAR has repair option, sometimes it helps.

  8. #8
    Member m^2's Avatar
    Join Date
    Sep 2008
    Location
    Ślůnsk, PL
    Posts
    1,611
    Thanks
    30
    Thanked 65 Times in 47 Posts
    Quote Originally Posted by Piotr Tarsa View Post
    Zip format stores descriptors at end of file. I think it's possible to extract only the downloaded parts when there's that information. WinRAR has repair option, sometimes it helps.
    Theoretically yes. Practically no. :P

  9. #9
    Administrator Shelwien's Avatar
    Join Date
    May 2008
    Location
    Kharkov, Ukraine
    Posts
    3,372
    Thanks
    213
    Thanked 1,020 Times in 541 Posts
    There's a known implementation for zip+http:
    http://www.movsd.com/source/zipdl.zip
    (Also some download managers seem to have a similar feature)
    I'm not aware of torrent clients supporting that, but its certainly possible.

    Now, as to solid archives, it may be possible to only download partial data for some formats, eg. rar/LZH -
    where entropy coding is blockwise.

Similar Threads

  1. ZPAQ self extracting archives
    By Matt Mahoney in forum Data Compression
    Replies: 31
    Last Post: 17th April 2014, 04:39
  2. MS CAB archives
    By nanoflooder in forum Data Compression
    Replies: 0
    Last Post: 10th April 2010, 01:58
  3. Multi-Volume Archives
    By osmanturan in forum Data Compression
    Replies: 12
    Last Post: 13th June 2009, 02:46
  4. GUI for creation of 7z-SFX-archives
    By Vacon in forum Forum Archive
    Replies: 0
    Last Post: 8th June 2007, 16:16

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •