bitsgalore
commented
6 years ago Birds of Europe CD
- Master Directory Block at offset 77824
- 1st Partition Map: HFS volume at block 150 (= offset 150*512 = 76800)
- Difference = 77824 - 76800 = 1024 = 2 sectors!
See isolyzer output
Zebra Verkeerstheorie
- Master Directory Block at offset 5632
- 1st Partition Map: HFS volume at block 9 (= offset 9*512 = 4608)
- Difference = 5632 - 4608 = 1024 = 2 sectors!
See isolyzer output.
According to Wikipedia entry on HFS:
- Logical blocks 0 and 1 of the volume are the Boot Blocks, which contain system startup information. For example, the names of the System and Shell (usually the Finder) files which are loaded at startup.
- Logical block 2 contains the Master Directory Block (aka MDB).
So assuming that references in partition map point to start of the HFS volume, it would make sense that MDB appears at 2nd block, hence the 1024 byte (2 block) difference!
So the procedure would be:
- Look out for for partition maps where partitionType is
Apple_HFSorApple_HFSX. - For these partition maps, locate corresponding MDB at partitionBlockStart + 2 sectors.
- Parse MDB using existing code and include results in Isolyzer output.
- Check if, with current code, this doesn't result in MDBs being read/reported twice.
For images created from many HFS-only CD-ROMS, the MDB that contains the name of the disc is located at a location that is different from described here and here.