1 DYNAMIC ADAPTIVE COMPRESSION TOOL 2 DACT 0.8.42 3 4Release information: 5 pkg: DACT version 0.8.42 6 url: http://www.rkeene.org/files/oss/dact/dact-0.8.42.tar.gz 7 web: http://www.rkeene.org/oss/dact/ 8 date: Mon May 31 23:32:43 CDT 2010 9-------------------------------------------------------------------------- 10 11From bugoptushome.com.au Thu May 10 21:40:21 2001 12Date: Sun, 06 May 2001 17:46:35 +1000 13From: Glenn McGrath <bugoptushome.com.au> 14To: Roy Keene <dactrkeene.org> 15Subject: dact: replacing tar 16 17Hello again, some more thoughts for you to consider. 18 19.tar.gz really sucks, im writting some code that works on files inside a 20.tar.gz in busybox and its a real hassle, i have to fork and uncompress 21in a child process and feed the uncompressed data back the main function 22that can untar it. 23 24The problem stems from the fact that the tar file is compressed rather 25than the individual files, if people did .gz.tar that it would be easy 26to work on individual files within the archive, but it wouldnt get as 27good compression due to the probably reduced block size (if the files 28are small). 29 30The loss in compression from appending files compressed with dact 31probably wouldnt be as bad as .tar.gz as dact can take advantage of 32different compresion methods for small files. 33 34The real reason i would like to see this could also tie in well with 35your url idea that you have been working on. 36 37If dact something like an index file that had a list of filenames, their 38offset and compressed size, then it would be possible to download and 39unpack only one file within an archive. 40 41e.g. linux-2.4.4.tar.gz is about 20MB, say i want to look at the 42./README file, to do so i have to download the entire 20MB, uncompress 43it, untar it, then access README. 44 45In would be good to start the download of linux-2.4.4.dct and read 46untill the end of the index section of the file and close the connection 47(or have the index file seperate), then with the index file i would know 48where abouts in the linux-2.4.4.dct the ./README file starts, so we 49could open a connection and start resuming the download from the offset 50of the ./README, rather than from the start of the file. 51 52You have mentioned you had ideas for combining multiple compressed 53files, so hopefully something like this could be worked into your plans. 54 55 56Glenn 57