README
上传用户:xiejiait
上传日期:2007-01-06
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- #
- # $Id: README,v 1.1 1997/02/23 16:14:56 eric Rel $
- #
- I am enclosing 3 test programs that I use to verify the
- integrity of an iso9660 disc. The first one (isodump) is pretty
- simple - it dumps to the screen the contents of the various
- directories. The second one (isovfy) goes through and looks for
- problems of one kind or another.
- To use, type something like "./isodump /dev/ramdisk" or
- "./isodump /dev/scd0", depending upon where the iso9660 disc is. It
- starts by displaying the files in the first sector of the root
- directory. It has some pretty simple one letter commands that you
- can use to traverse the directory tree.
- a - move back one sector.
- b - move forward one sector.
- g - go to new logical sector.
- q - quit
- The a and b commands do not try and stop you from going past the
- beginning or end of a sector, and the g command does not have any way
- of knowing whether the sector you request is actually a directory or
- not.
- The output is displayed in several columns. The first column
- is the total length of the directory record for the file. The second
- column (in [] brackets) is the volume number. Next comes the starting
- extent number (in hex), and then comes the file size in bytes. Then
- cones the filename (not the Rock Ridge version), and this is preceeded
- by an "*" if the file is a directory. After this is a summary of the
- Rock Ridge fields present along with a display of the translation of
- the symbolic link name if the SL Rock Ridge record is present.
- I tailored this program for debugging some of the problems
- that I was having earlier. The idea is that you can tailor it
- to test for problems that you might be having, so it is not intended
- as a be-all and end-all dump program.
- If you move to a sector that does not contain directory
- information, the results are unpredictable.
- The second program, isovfy, is run in the same way as isodump,
- except that you do not have to do much except let it run. I have it
- written to verify all kinds of different things, and as people find
- other sorts of problems other tests could be added.
- The third program, dump.c, basically does a hexdump of the cd.
- This is screen oriented, and there are some simple commands:
- a - move back one sector.
- b - move forward one sector.
- f - enter new search string.
- + - search forward for search string.
- g - go to new logical sector.
- q - quit
- Note that with the 'g' command, sectors are always given in
- hex, and represent 2048 byte sectors (as on the cdrom). If you know
- how to decode a raw iso9660 directory, you can pick out the starting
- extent number from the hexdump and know where to go from there. The
- starting extent appears something like 30 bytes prior to the start of
- the iso9660 (not Rock Ridge) filename, and it appears in a 7.3.3
- format (meaning that it occupies 8 bytes, 4 in little endian format,
- and 4 in big endian format). Thus you should see a mirror image of
- the bytes when looking at the extent number.
- The isovfy program can also dump the contents of the path
- tables, but this capability is commented out right now. Feel free
- to enable this to see what is in the tables. Ultimately I may fix
- it so that this checks the integrity of the tables as well.
- The isovfy program gives warnings about things like files that
- have a size of 0 but have an extent number assigned. The mkisofs program
- should never do this, but the YM software does leave these around.
- I think it is probably harmless in the YM case.~