This is the mail archive of the
cygwin
mailing list for the Cygwin project.
Re: a few tar.xz packages are bigger than their uncompressed tar
- From: Andrey Repin <anrdaemon at yandex dot ru>
- To: Jérôme Bouat <jerome dot bouat at laposte dot net>, cygwin at cygwin dot com
- Date: Wed, 27 Sep 2017 07:47:42 +0300
- Subject: Re: a few tar.xz packages are bigger than their uncompressed tar
- Authentication-results: sourceware.org; auth=none
- Authentication-results: smtp4o.mail.yandex.net; dkim=pass header.i=@yandex.ru
- References: <cc1a2cd5-a947-624e-4473-73151794a5d7@laposte.net>
- Reply-to: cygwin at cygwin dot com
Greetings, Jérôme Bouat!
> Hello,
> I looked into the local folder where the downloaded packages are saved
> before they are installed. I noticed that a few compressed archives files
> are using more size than their uncompressed form. For example, the
> libstdc++6-6.4.0-1.tar.xz file uses more space than its uncompressed tar file (on cygwin x86_64).
$ ls -ld "libstdc++6-6.4.0-1.tar.xz" ; tar tf "libstdc++6-6.4.0-1.tar.xz" -v
-rw-r--r-- 1 anrdaemon None 282724 сен 18 20:17 libstdc++6-6.4.0-1.tar.xz
-rwxr-xr-x Blue/None 1367059 2017-09-10 01:23 usr/bin/cygstdc++-6.dll
$ sha512sum.exe libstdc++6-6.4.0-1.tar.xz
734f6f91003588c82bccfc016d89414cd25ea6560484391c1424513f053b3e0f3e9932e317740804c10d90e6f9fd99d4d198cf8ea953da22969aab50182f4c74 *libstdc++6-6.4.0-1.tar.xz
# Matches the one in setup.ini
> That is not surprising. All compression methods may sometimes inflate the final amount of data.
> Would it be a way to keep the tar archive file uncompressed if the compressed form needs more space ?
Compression MAY inflate the file, but never by an order of magnitude.
At worst, it will be inflated by the size of metadata describing all blocks in
order.
--
With best regards,
Andrey Repin
Wednesday, September 27, 2017 07:43:04
Sorry for my terrible english...