Archive for May 2015



Mount encrypted QNAP disk (crypto_LUKS) on an external computer

If one attempts to mount a QNAP disk encrypted with LUKS without unlocking it first, the following error will be shown:
mount: unknown filesystem type 'crypto_LUKS'

To mount and read data from a disk encrypted with crypto_LUKS (for example from a QNAP backup), use cryptsetup as per the below:

Install cryptsetup if not already installed:
sudo apt-get install cryptsetup

Unlock the disk (in this case /dev/sdb1 – adjust based on the device you wish to unlock). Select a good name for the unlocked disk. In this case we use “cryptodisk” but any name will work:

sudo cryptsetup luksOpen /dev/sdb1 cryptodisk
Enter passphrase for /dev/sdb1: 

The disk will be listed under /dev/mapper/. In this case /dev/mapper/cryptodisk:
sudo mount /dev/mapper/cryptodisk /home/user/mount/usb/

Now data can be accessed as normal via the mount point /home/user/mount/usb/

To unmount, do the following:
sudo umount /home/user/mount/usb

Finally lock the disk:
sudo cryptsetup luksClose cryptodisk

Stopping X windows / dropping to single-user mode

Installing the NVIDIA driver on Linux requires dropping to a command prompt without X windows running in the background.

Switch to root user:

su -

Stop the window manager:
/etc/init.d/gdm3 stop

After this X windows will stop and a command prompt will be displayed. The option to enter the root password will be given. Enter it and then install the driver as root. To install the driver, do one of the following:

Option 1:
sh ./

Option 2:

chmod 755

When done, start X windows again with:
/etc/init.d/gdm3 start

Speaker at Tokyo Big Sight today :-)

2015-05-15 - BigSight IT Week Expo