Hi Tim, Good question, and thanks for getting back to me.
The nice thing about tar is that it is very serial-device optimized. Though that is because of it's Tape ARchive history, it also makes for every efficient operation for the type of work that we do. Are you sure that zip operates as I described? We've experimented with zip, and doing operations such as appending a file resulted in much more disk utilization than our perl-hack, which simply appends onto the end of the file. I guessed that zip must be doing more than just appending onto the end of the file. Thanks, -Carl Carl Eklof President @ BeeSoftware [email protected] | p: 424.888.4BEE | f: 801.439.4213 | http://beesw.com/ ________________________________ From: Tim Kientzle <[email protected]> To: Carl Eklof <[email protected]> Cc: "[email protected]" <[email protected]> Sent: Sunday, October 30, 2011 4:23 PM Subject: Re: [Bug-tar] Solution to updating compressed archives: Pre-compress files On Oct 29, 2011, at 10:04 AM, Carl Eklof wrote: > Problem: > I frequently run into situations where I need to update archives. I of course > also want to conserve space so I use compression. These two desires are not > directly supported in the current version of tar. > > Solution: > The solution requires two parts of the code to be modified: > 1) Compress each file before adding it to the archive. > 2) Upgrade the tar section of meta about each file in the archive to provide >storage space for specifying what compression algorithm/program is used for >that file (if any). Why do you need "tar" to do this? "zip" does exactly what you describe, and newer Info-Zip versions do a good job of preserving Unix permissions, timestamps, etc. Tim
