From: Alain.Knaff@imag.fr (Alain Knaff)
Newsgroups: comp.os.linux.announce
Subject: Zlibc-0.4 - Replacement for read-only compressed filesystem.
Date: 4 Dec 1993 01:15:58 +0200
Approved: linux-announce@tc.cornell.edu (Lars Wirzenius)
Message-ID: <2dohbe$gsv@klaava.Helsinki.FI>

 I have uploaded zlibc-0.4 to sunsite.unc.edu:/pub/Linux/Incoming,
to tsx-11:/incoming and to ftp.imag.fr:/pub/ZLIBC/0.4
 It will soon be moved to /pub/Linux/libs on sunsite.

 Zlibc is a library patch that allows executables to uncompress their
datafiles on the fly. No kernel patch, no recompilation of these
executables and no recompilation of the libraries is needed. Using
gzip -9, a compression ratio of 1:3 can easily be achieved! (See
examples below). This program has (almost) the same effect as a
(read-only) compressed file system.

 How to install it:
 ==================

 There is a source distribution, called zlibc-0.4.src.tar.gz and a binary
distribution, called zlibc-0.4.bin.tar.gz. The source distribution is the
recommended way of installing zlibc, as it contains a configure script
and an automated install script.

 To install from source, type tar xfzvvp zlibc-0.4.src.tar.gz, and read 
zlibc-0.4/INSTALL.linux for further instructions.

 To install the binary version, type cd / ; tar xfzvvp zlibc-0.4.bin.tar.gz,
and read /usr/doc/zlibc/INSTALL.linuxbin for further instructions.


 New in this release:
 ====================

 This is the second public release of zlibc. This is essentially a bug
fix release, there are no new features. The following bugs have been
fixed since the 0.3 release:

 * 'at' (on Linux) and 'du' (on Sun) work now.
 * The installation script has been entirely reworked in order to use ldconfig
instead of ln -sf.
 * The documentation has been improved. There is a FAQ now. A regularily updated
 version of this FAQ can be found at ftp.imag.fr:/pub/ZLIBC/ALPHA. I will also
 place minor updates and bugfixes into this directory.
 * The documentation is now also included in the binary release: It
goes to /usr/doc/zlibc and /usr/man when you untar it on the root
directory. Read the file /usr/doc/zlibc/INSTALL.linuxbin first.
 * 'rm' behaves more intuitively now.

 How it works:
 =============

 This package patches the "open" function (and other similar system
call functions) in the shared library. You don't need to have the
sources of the shared library, the binary is patched directly.

 On Linux, this package should work with every .4 shared library
(tested on 4.3.3, 4.4, 4.4.1, 4.4.4). This is because it patches the
jumptable, and the jumptable should remain constant for the same major
release number (4) of the shared library.

 On SunOs, this package uses the LD_PRELOAD/LD_LIBRARY_PATH mechanism
to redirect the dynamic linker to use the relevant functions out of
uncompress.o instead of the shared library. Thus, it should work with
every release of the shared library (tested on libc.so.1.7). On SunOs,
you don't need to be superuser to install this package.


 Examples: (compressed with gzip -9)
 ===================================

				Before				After
/usr/info/			1568k				521k
/usr/lib/emacs/19.19/		6750k				2550k

/usr/local/smalltalk/		326k				126k
/usr/local/lib/lisp		2256k				779k

/usr/lib/*.a 			1094k				476k
/usr/X386/lib/*.a 		1110k				470k
/usr/include			655k				325k

/usr/lib/X11/fonts/75dpi/	3158k (1531 compressed)		1095 (gzipped)
/usr/lib/X11/fonts/Speedo/	530k (479 compressed)		373 (gzipped)
/usr/lib/X11/fonts/misc/	892k (323 compressed) 		254 (gzipped)

/usr/TeX/macros/		1167k				223k (sic!)
/usr/TeX/inputs			242k				74k
/usr/TeX/formats		779k				251k


-- 
 Alain

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