Hi, > growisofs's CD001
That's actually mkisofs's "CD001". growisofs -M examines media TOC resp. the ECMA-119 PVD in order to get the parameters for a run of mkisofs -C . growisofs then starts mkisofs and writes its output to the media. In case of overwriteable media it finally copies the Volume Descriptors of the new session to the start of the media. xorriso does about the same but uses libraries libisofs, libburn and libisoburn. On overwriteable media it puts the first session to LBA 32 rather than 0. This protects the PVD of the first session from being overwritten by the PVD copies of further sessions. So it is possible to follow a chain of sessions when printing a table-of-content. > Indeed I have been frustrated trying to find out a description of > multi-session ECMA-119 layout. The idea is quite simple: Mount uses as superblock address the start of the first track in the last session. At this address it expects a System Area of 16 blocks followed by a Volume Descriptor Set. It is interested in the PVD which tells the address of the Directory Entry of the root directory and the size of the image. The only deviation from ECMA-119 is that the superblock address is not 0. Prescribed is: "6.2.1 System Area and Data Area The System Area shall occupy the Logical Sectors with Logical Sector Numbers 0 to 15. [...] 6.7.1 Volume Descriptor Set A Volume Descriptor Set shall be a sequence of volume descriptors recorded in consecutively numbered Logical Sectors starting with the Logical Sector Number 16." Everything else in our doings follows ECMA-119 resp. squeezes itself into the niches which have been left open in that standard. E.g. SUSP, Rock Ridge, AAIP use a few reserve bytes of each directory entry to attach extra info and make ISO 9660 a decent filesystem. On sequential media we formally fulfill the demands of ECMA-119 by having an outdated system area and Volume Descriptor Set at addresses 0 and 16. On overwriteable media we fulfill ECMA-119 completely by putting an updated copy of the prescribed stuff to LBA 0 to 16. The El-Torito specs for booting support our interpretation of ECMA-119 liberty by prescribing to use the "System Area" of the last session. Nevertheless many BIOSes stick to ECMA-119 and insist in using the System Area at LBA 0 and the El-Torito boot record at LBA 17 to 31. So bootable multi-session CDs and DVDs should in each session point to the same boot objects in the image which should all sit in the first session. > (To wit, the Volume Space Size field from the > Primary Volume Descriptor from ECMA-119 doesn't fully account for the > difference between sessions.) Oh it does. But each PVD can only give the end address of its own session. So you will see an increasing volume size in each session. It is always counted from LBA 0 and not from the start LBA of the session. I.e. a PVD covers its own session and all older sessions. > system identifier, volume identifier, volume set identifier, > publisher identifier, data preparer identifier, application > identifier, copyright file identifier, abstract file identifier, > bibliographic file identifier. How about this: $ xorriso -indev /dev/... -pvd_info ... System Id : ... Volume Id : ... Volume Set Id: ... Publisher : ... Preparer : ... Application : ... Copyright Id : ... Abstract Id : ... Bibliogr. Id : ... Have a nice day :) Thomas -- To UNSUBSCRIBE, email to [email protected] with a subject of "unsubscribe". Trouble? Contact [email protected]
