15.10 Installer cannot see my existing linux partition

[Maneer]

Someone brought be an old Lenovo 32 bit laptop running Lubuntu 12.10 and asked me to update it. Something went wrong with:


$ sudo apt-get update && sudo do-release-upgrade -d

I am left with a system which fails to boot. No problem, I backed up my user directory from a live USB and I can install Lubuntu 15.10 in the existing Gnu/Linux partition - right?

Unfortunately, the existing partition structure seems to be invisible to the 15.10 installer and to the latest version of Gparted, which reports the entire hard disk as a single Fat16 partition (see image attached).

The same partitions which are invisible to Gparted appear as normal in the Places sidebar, of the PCManFM file manager. They can be mounted and used, seemingly without issue. Below, is the shell output of fdisk, which can see the partition structure and parted, which cannot:


$ sudo fdisk -lu

Disk /dev/sda: 74.5 GiB, 80026361856 bytes, 156301488 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x0000000a

Device Boot Start End Sectors Size Id Type
/dev/sda1 * 63 20482874 20482812 9.8G c W95 FAT32 (LBA)
/dev/sda2 20482997 146880511 126397515 60.3G f W95 Ext'd (LBA)
/dev/sda3 146882295 156296384 9414090 4.5G 12 Compaq diagnostics
/dev/sda5 20482999 122881184 102398186 48.8G 6 FAT16
/dev/sda6 122882048 145854463 22972416 11G 83 Linux
/dev/sda7 145856512 146880511 1024000 500M 82 Linux swap / Solaris

Partition table entries are not in disk order.



$ sudo parted -l

Model: ATA TOSHIBA MK8034GS (scsi)
Disk /dev/sda: 80.0GB
Sector size (logical/physical): 512B/512B
Partition Table: loop
Disk Flags:

Number Start End Size File system Flags
1 0.00B 80.0GB 80.0GB fat16



NB: This issue is not unique to Lubuntu. I have had similar experience on a machine upgraded from Debian Wheezy to Debian Jessie. The updated version of Gparted on that machine also behaves as described above, where the Wheezy version of Gparted could see the same partitions perfectly.

[sudodus]

Is there anything (more) on the drive that you need to backup? In that case please do it now :-) because what you will do next is risky for the data.

When you are happy with the backup, I suggest that you consider removing the current partition table and start with a fresh one, that is likely to work with the current linux tools.

If you really want to keep the current partitions, you can try installing like you suggested to the linux partition, but some tools will probably continue to fail, and that partition is rather small, 11 GB, I would say too small except for testing.

[grahammechanical]

Why did you use?


sudo do-release-upgrade -d

Of course something is going to go wrong. The -d switch is an instruction to upgrade to a development version and the only development version in town is 16.04. But we cannot upgrade to 16.04 from 12.10. Only from 14.04 or 15.10.

With Ubuntu/Lubuntu we can upgrade directly from one LTS to the next LTS or from one interim release to the next interim release or from an interim release to an LTS release if the LTS is the next release.

Also, 12.10 has been out of life since 16 May 2014. Its repositories are now closed and have been archived. So, the URLs in the software sources list are inaccurate. So, even


sudo apt-get update && sudo apt-get upgrade

will give errors.

[Maneer]

Thank-you sudodus. I could indeed do as you suggest, repartition the whole hard disk and begin from scratch. However, since I have now had similar experience on two different machines under both Unbuntu and Debian. I think that there is probably a cause which I should try to understand. The latest version of Ubuntu (and Debian) must be addressing partitions in a different way to pervious versions, perhaps?

In my experience, 11 GB is quite sufficient for an LXDE based Ubuntu (or Debian) install. One can use Bleachbit from time to time to clear out any bloat. That said, if Gparted could see the partitions, I could resize them.

[sudodus]

I'm not sure what is the problem. But the first partition start at sector 63, which is obsolete now. It should start at 2048 (one mibibyte). I don't know if that is causing the problem for you, maybe. The space after the first sector (512 bytes) of the first mibibyte should be reserved for grub, and it does not work when the first partition starts at sector 63.


Device Boot Start End Sectors Size Id Type
/dev/sda1 * 63 20482874 20482812 9.8G c W95 FAT32 (LBA)

[Maneer]

Since this issue also effects Debian, the question has been asked on Debian forums.This thread is located at:http://forums.debian.net/viewtopic.php?f=17&t=126542&p=604362&e=604362

[sudodus]

Since you have nothing important in the drive (as described also at the Debian forum), I suggest that you create a new partition table (with gparted) and after that try to install a current version of Ubuntu and / or Debian.

If there are still problems, you can try via the wipe menu of mkusb (https://help.ubuntu.com/community/mkusb/wipe).

[kansasnoob]

Look at your partition table type in parted -l again and you'll see it's identified as "loop", then read this:

http://lists.alioth.debian.org/pipermail/parted-devel/2009-May/002840.html

Basically "loop" is not a true partition table but may appear on some drives that have been used for LVM or RAID setups. Most older computers should have an msdos partition table. Newer computers that are capable of using UEFI boot should have a gpt partition table. Creating a new partition table on a drive completely erases that drive!