On Sun, 21 Oct 2007, William Case wrote: > Hi; > > As a result of the ongoing GRUB discussion, I have been trying to > trace the use of GRUB from BIOS to the end of GRUB stage 2. I am > particularly interested in seeing how the MBR is used. all the MBR does is: 1) provide up to 446 bytes of initial boot code (446 bytes) 2) define the four entries of the partition table (4 @ 16 bytes) 3) have a boot block signature of x'55aa' at the end (final 2 bytes) if you add that up, you get 512. > I can create a temporary copy of my MBR using: > # dd if=/dev/sdX of=/tmp/sda-mbr.bin bs=512 count=1 yup, so far, so good. > My question is; what program should I use to read this file in a human > meaningful way (hexdump??)? # hexdump -C /dev/sda | less (for example) > I am trying to see how the MBR names partitions; and how GRUB uses > those names. the MBR does not "name" partitions, it simply defines them. any "names" assigned to devices and partitions are OS-specific. > That is, are the partitions named in MBR actually named hd0,0 (ie > the binary or hex equivalent of hd0,0) etc. or is there a further > translation step required by GRUB? Does the device/partitioning > system used by MBR and GRUB have a name(s)? (For Internet search > purposes). again, the MBR itself does not "name" the partitions. the notation used by GRUB -- (hd0,0) for example -- simply defines the first disk, first partition. try not to think of it as a "name". it's just an identifier. rday -- ======================================================================== Robert P. J. Day Linux Consulting, Training and Annoying Kernel Pedantry Waterloo, Ontario, CANADA http://crashcourse.ca ========================================================================
