From 46186e5f06a2bbc958d8e512384823686ed87721 Mon Sep 17 00:00:00 2001 From: Thomas Schmitt Date: Thu, 29 Oct 2020 08:31:31 +0100 Subject: [PATCH] Added Z2 System Use Entry Format to zisofs2 specs --- doc/zisofs2_format.txt | 25 ++++++++++++++++++++++++- 1 file changed, 24 insertions(+), 1 deletion(-) diff --git a/doc/zisofs2_format.txt b/doc/zisofs2_format.txt index fccbfb1..1d40949 100644 --- a/doc/zisofs2_format.txt +++ b/doc/zisofs2_format.txt @@ -12,7 +12,7 @@ The zisofs2 format was invented by Valentín KIVACHUK BURDÁ and Thomas SCHMITT (as extension of zisofs by H. Peter Anvin). It compresses data file content, marks it by a header and provides a pointer array for coarse random access. Within a RRIP enhanced ISO 9660 image the format -is additionally marked by a System Use entry with signature "ZF". +is additionally marked by a System Use entry with signature "ZF" or "Z2". The uncompressed size of a single zisofs2 compressed file is restricted to 2^64 - 1 bytes. Larger files shall not be compressed. @@ -146,6 +146,25 @@ Example (block size 128 kiB, uncompressed file size = 40 TB): 0x00, 0x80, 0xCA, 0x39, 0x61, 0x24, 0x00, 0x00 } + Z2 System Use Entry Format + +Linux kernels which are configured by CONFIG_ZISOFS to recognize zisofs +but are not aware of zisofs2 will complain about ZF entries which announce +algorithms other than "pz". The system log will show for each zisofs2 +compressed file at first stat(2) or open(2) a line like this: + + isofs: Unknown ZF compression algorithm: PZ + +To avoid these complaints, it is possible to use + + [1] "BP 1 to BP 2 - Signature Word" shall be (5A)(32) ("Z2"). + +instead of "ZF" with the System Use Entry Format specified above. +Everything else shall be like in ZF format version 2, including the version +number itself: + + [3] "BP 4 - System Use Entry Version" shall be 2 as in ISO 9660:7.1.1. + **LEGACY** @@ -225,6 +244,10 @@ SUSP 1.12 RRIP 1.12 ftp://ftp.ymi.com/pub/rockridge/rrip112.ps +zisofs version 1 + libisofs-*/doc/zisofs_format.txt + https://dev.lovelyhq.com/libburnia/libisofs/raw/branch/master/doc/zisofs_format.txt + --------------------------------------------------------------------------- This text is under