Hi, mick.crane wrote: > > > root@pumpkin:~# fdisk -l /dev/sda > > > Disk /dev/sda: 223.57 GiB, 240057409536 bytes, 468862128 sectors > > > ... > > > Disklabel type: dos > > > ... > > > Device Boot Start End Sectors Size Id Type > > > /dev/sda1 * 2048 466862079 466860032 222.6G 83 Linux > > > /dev/sda2 466864126 468860927 1996802 975M 5 Extended > > > /dev/sda5 466864128 468860927 1996800 975M 82 Linux swap / > > > Solaris
Michael wrote: > as i interpret this, the disk in questions has a dos partition table... Indeed. (And as mick.crane already noticed, it is a bit awkward to create an extended partiton 2 only to fill it nearly up with logical partition 5. I wonder what entity decided to do so.) David Christensen wrote: > > Did you zero your drive prior to installing Debian? Perhaps there > > is a leftover GPT secondary partition table on disk. See below. > on a disk with a gpt partition table, yes. > maybe i am missing something. if so, please enlighten me! A remnant backup GPT is a typical risk of repartitioning a USB stick from GPT to MBR Partition Table. Such repartitioning happens e.g. if you put a Debian installation or Live ISO onto a previously GPT partitioned stick. (xorriso-dd-target zeros the last block of the target stick in order to prevent partition editors from re-creating the previous GPT partitioning.) > > Your disk has 468862128 sectors. A GPT secondary partition table > > should start 33 sectors before the end of the disk: Here i disagree. The size of the GPT partition array is adjustable. 32 blocks of 4 entries each is a usual size. But actually you have to read from the GPT header block the 4 bytes beginning at offset 80 as little-endian number to get the number of array blocks (by dividing by 4). The start block of the partition array is adjustable, too: Offset 72, 8 bytes as 64-bit little-endian number. The position of the GPT header is always 512-byte block 1 for the primary partition table and the last valid block address of the device for the backup table. Specs for GPT are part of the UEFI specs. Current is: https://uefi.org/specs/UEFI/2.10/05_GUID_Partition_Table_Format.html (I myself am still reading version 2.6 ...) > > Run the following command to see if there is a GPT secondary partition > > table on your disk: > > # dd bs=512 count=33 if=/dev/sda skip=468862095 | hexdump -C So i would rather propose to inspect the last block, whether it begins by the bytes "EFI PART\000\000\001\000" (meaning GPT version 1.0): dd bs=512 count=1 if=/dev/sda skip=468862127 | hexdump -C Have a nice day :) Thomas
