"Fossies" - the Fresh Open Source Software Archive  

Source code changes of the file "doc/checksums.txt" between
xorriso-1.5.2.tar.gz and xorriso-1.5.4.tar.gz

About: GNU xorriso creates, loads, manipulates and writes ISO 9660 filesystem images with Rock Ridge extensions. It is suitable for incremental data backup and for production of bootable ISO 9660 images. GNU xorriso is a statical compilation of the libraries libburn, libisofs, libisoburn, and libjte.

checksums.txt  (xorriso-1.5.2):checksums.txt  (xorriso-1.5.4)
skipping to change at line 78 skipping to change at line 78
Tag_id pos=# range_start=# range_size=# [session_start|next=#] md5=# self=#\n Tag_id pos=# range_start=# range_size=# [session_start|next=#] md5=# self=#\n
Tag_id distinguishes the following tag types Tag_id distinguishes the following tag types
"libisofs_rlsb32_checksum_tag_v1" Relocated 64 kB superblock tag "libisofs_rlsb32_checksum_tag_v1" Relocated 64 kB superblock tag
"libisofs_sb_checksum_tag_v1" Superblock tag "libisofs_sb_checksum_tag_v1" Superblock tag
"libisofs_tree_checksum_tag_v1" Directory tree tag "libisofs_tree_checksum_tag_v1" Directory tree tag
"libisofs_checksum_tag_v1" Session tag "libisofs_checksum_tag_v1" Session tag
A relocated superblock may appear at LBA 0 of an image which was produced for A relocated superblock may appear at LBA 0 of an image which was produced for
being stored in a disk file or on overwriteable media (e.g. DVD+RW, BD-RE). being stored in a disk file or on overwritable media (e.g. DVD+RW, BD-RE).
Typically there is a first session recorded with a superblock at LBA 32 and Typically there is a first session recorded with a superblock at LBA 32 and
the next session may follow shortly after its session tag. (Typically at the the next session may follow shortly after its session tag. (Typically at the
next block address which is divisible by 32.) Normally no session starts after next block address which is divisible by 32.) Normally no session starts after
the address given by parameter session_start=. the address given by parameter session_start=.
Session oriented media like CD-R[W], DVD+R, BD-R will have no relocated Session oriented media like CD-R[W], DVD+R, BD-R will have no relocated
superblock but rather bear a table-of-content on media level (to be inquired superblock but rather bear a table-of-content on media level (to be inquired
by MMC commands). by MMC commands).
Example: Example:
skipping to change at line 128 skipping to change at line 128
pos= pos=
gives the block address where the tag supposes itself to be stored. gives the block address where the tag supposes itself to be stored.
If this does not match the block address where the tag is found then this If this does not match the block address where the tag is found then this
either indicates that the tag is payload of the image or that the image has either indicates that the tag is payload of the image or that the image has
been relocated. (The latter makes the image unusable.) been relocated. (The latter makes the image unusable.)
range_start= range_start=
The block address where the session is supposed to start. If this does not The block address where the session is supposed to start. If this does not
match the session start on media then the volume descriptors of the match the session start on media then the volume descriptors of the
image have been relocated. (This can happen with overwriteable media. If image have been relocated. (This can happen with overwritable media. If
checksumming started at LBA 0 and finds range_start=32, then one has to checksumming started at LBA 0 and finds range_start=32, then one has to
restart checksumming at LBA 32. See libburn/doc/cookbook.txt restart checksumming at LBA 32. See libburn/doc/cookbook.txt
"ISO 9660 multi-session emulation on overwriteable media" for background "ISO 9660 multi-session emulation on overwritable media" for background
information.) information.)
range_size= range_size=
The number of blocks beginning at range_start which are covered by the The number of blocks beginning at range_start which are covered by the
checksum of the tag. checksum of the tag.
Only with superblock tag and tree tag: Only with superblock tag and tree tag:
next= next=
The block address where the next tag is supposed to be found. This is The block address where the next tag is supposed to be found. This is
to avoid the small possibility that a checksum tag with matching position to avoid the small possibility that a checksum tag with matching position
skipping to change at line 227 skipping to change at line 227
and range_size match the state of block reading, and whether the returned and range_size match the state of block reading, and whether the returned
bytes in parameter md5 match the MD5 computed from the data blocks which were bytes in parameter md5 match the MD5 computed from the data blocks which were
read before the tag block. read before the tag block.
Checking All Sessions Checking All Sessions
If the media is sequentially recordable, obtain a table of content and check If the media is sequentially recordable, obtain a table of content and check
the first track of each session as prescribed above in Checking Before Image the first track of each session as prescribed above in Checking Before Image
Tree Loading and in Checking the Data Part of the Session. Tree Loading and in Checking the Data Part of the Session.
With disk files or overwriteable media, look for a relocated superblock tag With disk files or overwritable media, look for a relocated superblock tag
but do not hop to address next_tag (given by session_start=). Instead look at but do not hop to address next_tag (given by session_start=). Instead look at
LBA 32 for the first session and check it as prescribed above. LBA 32 for the first session and check it as prescribed above.
After reaching its end, round up the read address to the next multiple of 32 After reaching its end, round up the read address to the next multiple of 32
and check whether it is smaller than session_start= from the super block. and check whether it is smaller than session_start= from the super block.
If so, expect another session to start there. If so, expect another session to start there.
Checking Single Files in a Loaded Image Checking Single Files in a Loaded Image
An image may consist of many sessions wherein many data blocks may not belong An image may consist of many sessions wherein many data blocks may not belong
to files in the directory tree of the most recent session. Checking this to files in the directory tree of the most recent session. Checking this
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