AW: [Oberon] Re. cloning a filesystem or an OS.
Stauber Sven Philipp
sven.stauber at inf.ethz.ch
Fri Feb 15 14:24:28 MET 2008
I'm not familiar with the details of the Oberon filesystem, but here some general remarks about resizing file systems:
Besides the actual data, there's a lot of metadata on a filesystem. Example: In FAT file systems, there are file allocation tables which basically tell you for each block of a file which block is the next in the sequence. Therefore, you need one entry in earch FAT for each data block. Also, the file system has something like a configuration section that in the FAT example would tell you the size and position of the FAT within the partition the filesystem is located.
Filesystem < new partition:
FAT example: You cannot simply use the additional space since you would have to adapt the size of the file allocation tables on the disk and also the configuration section. If you would make the FAT larger, you would have to move files that are possibly located directly after the FAT on the disk.
Filesystem > new partition:
Beside the adaptions above you would have to move files to the front of the partition (e.g. defragment the filesystem which typically does that)
As I said, I don't no details of the Oberon filesystem, but if you have a look at the format operation, it at least stores the partition size in the file system configuration...
Bootfile: Currently, there is no operation that extracts the boot file from a partition, but this could be done.
The boot loader is located in the partition where the file system is located (not in the MBR!). The assembler source code of the Oberon Bootloader is contained in the release (BBL.Asm). Also, the sources of MBR (OBEMBR4.ASM) and the boot manager (BootManager.Asm) are available.
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