Hallo Herr Eric Auer, am Dienstag, 8. Juni 2021 um 20:47 schrieben Sie:
> Hi Tom, >> ELTORITO does NOT create a sector oriented device, accesible by the >> kernel (or LBACACHE). it can't be accessed by INT13 READ/WRITE >> functions and so can't be cached by LBACACHE. > The workflow is that the boot process activates ELTORITO mode > in the BIOS, which then creates an int 13 representation of > the bootable CD/DVD as 2048 byte per sector LBA drive. I was not aware of this. And this might indeed present a problem. I had hoped for this interface (BIOS access to CD media) for the last 30+ years. at least at boot ime is at least something... > Then > the ELTORITO DOS driver uses int 13.42 to fetch CD/DVD sector > contents whenever SHSUCDX requests sector data from ELTORITO. > Because LBACACHE is an int 13 based cache with LBA support, > I see the risk that it will try to cache BIOS responses to > LBA int 13 requests from the ELTORITO driver, which causes > the risk that it returns WRONG data to ELTORITO when sectors > are read multiple times and the cache believes it can help, > while actually having cached only the first 512 bytes of the > cached CD/DVD sector data. your reasoning seems OK. so I assume LBACACHE is not used on boot disks so far. otherwise we would know this as disk access would pretty soon break if only 512 bytes are returned when 2048 are expected. > So LBACACHE does not know about the CDEX communications of > the ELTORITO driver with SHSUCDX, but it may intercept the > int 13 communications between the ELTORITO driver and BIOS. time for LBACACHE to check if the drives it caches have the expected sectror sizes. Tom _______________________________________________ Freedos-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/freedos-devel
