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