Technology Tales

Adventures & experiences in contemporary technology

Wiping of hard drives with Linux

2nd December 2013

More than a decade of computer upgrades and rebuilds can leave obsolete kit in your hands and the arrival of legislation controlling the dumping of electronic goods during this time can leave one wondering how anyone can dispose of them. Thankfully, I discovered that the local council refuse site only a few miles away from me accepts such things for recycling and saw me a good few times over the last summer with obsolete and non-working gadgets that has stayed with me far too long. Some were as bulky as a computer monitor and a printer but others were relatively diminutive.

Disposing of non-working and utterly obsolete equipment is an easy choice but I find this is harder when a device still works as intended and even might have a use yet. When you realise that computer motherboards still come with PS/2, floppy and IDE ports, things get trickier. My Gigabyte Z87-HD3 mainboard just has one PS/2 when predecessors would have had two and the same applies to IDE sockets and there still is a floppy drive socket on there too, a surprising sight for anyone used to thinking that such things are utterly outmoded these days. So, PC technology isn’t relinquishing backwards compatibility just yet since that mainboard is part of a system with an Intel Core i5-4670K CPU and 24 GB of RAM on there.

Even with that presence of an IDE port, I was not tempted to use leftover 10 GB and 20GB hard drives that I have had for just over a decade. Ten years ago, that sort of capacity would been respectable were it not for our voracious appetite for data storage thanks to photography, video and music. Apart from the size constraints, the speed of those drives cannot compare well with what we have today either and I quickly saw that when I replaced a Samsung 160 HD of a similar age with a Samsung SSD.

The result of this line of thought was that I was minded to recycle the drives so I started to think about wiping and Linux has a good tool for this in the form of the dd command. It can overwrite data on the disks so as to render the information virtually irretrievable. Also, Linux has a number of dummy devices that can supply junk data for overwriting purposes. They are like /dev/null which is used to suppress the issuing of output to the command. The first is /dev/zero which supplies octal zeros and I have used this. However, there also is /dev/random and /dev/urandom for those wanting a more random element to the overwriting.

To overwrite data on a disk with zeroes while having feedback on progress, the following command achieves the required result:

sudo dd if=/dev/zero | pv | sudo dd of=/dev/sdd bs=16M

The whole operation needs to be executed with root privileges and the if parameter of dd specifies the input data and this is sent to a pv command that shows a progress bar that dd would not produce by itself while sending the output on to another dd command with the disk to be overwritten specified using the of parameter. The bs parameter in that second dd command specifies the block size for the disk writing job. Unfortunately, pv is not installed by default so you need to add it yourself. On a Debian, Ubuntu or Linux Mint system, the command is the following:

sudo apt-get install pv

That pv sandwich also is invaluable for those times when dd is needed to copy partitions between different physical or virtual (in a virtual machine) disks. Without it, you might wonder what exactly is happening in the silence and that especially is concerning when you are retrying an operation that failed previously and it takes a while to complete each time.

A look at Ubuntu GNOME 13.10

12th October 2013

With its final release being near at hand, I decided to have a look at the beta release of Ubuntu GNOME 13.10 to get a sense of what might be coming. A misstep along the way had me inadvertently download and install the 64-bit edition of 13.04 into a VirtualBox virtual machine. The intention to update that to its soon to be released successor was scuppered by instability so I never did get to try out an in situ upgrade to 13.10. What I had in mind was to issue the following command:

gksu update-manager -d

However, I found another one when considering how Ubuntu Server might be upgraded without the GUI application that is the Update Manager. To update to a development version, the following command is what you need:

sudo do-release-upgrade -d

To upgrade to a final release of of a new version of Ubuntu, drop the -d switch from the above to use the following:

sudo do-release-upgrade

There is one further option that isn’t recommended for moving between Ubuntu versions but I use it to get updates such as new kernel subversions that are released:

sudo apt-get dist-upgrade

Rather than trying out the above, I downloaded the latest ISO image for the beta release of Ubuntu GNOME 13.10 and installed onto a VM that instead. Though it is the 32 bit version of the distro that is installed on my main home PC, it has been the 64 bit version that I have been trying. So far, that seems to be behaving itself even if it feels a little sluggish but that could be down to the four year old PC that hosts the virtual machine. For a while, I have been playing with the possibility of an upgrade involving an Intel Core i5 4670K CPU and 16 GB of RAM (useful for running multiple virtual machines at a time) along with any motherboard that supports those so looking at a 64 bit operating system has its uses.

The Linux kernel may be 3.11 but that is not my biggest concern. Neither is the fact that LibreOffice 4.1.2.3 was included and GIMP wasn’t, especially when that could be added easily anyway and it is version 2.8.6 that you get. The move to GNOME Shell 3.8 was what drew me to seeing what was coming because I have been depending on a number extensions. As with WordPress and plugins, GNOME Shell seems to have a tempestuous relationship with some of its extensions and I wanted to see which ones still worked. There also has been a change to the backstage application view in that you either get all installed applications displayed when you browse them or you have to start typing the name of the one you want to select it. Losing the categorical view that has been there until GNOME Shell 3.6 is a step backwards and I hope that version 3.10 has seen some sort of a reinstatement. There is a way to add these categories and the result is not as it once was either; also, it shouldn’t be necessary for anyone to dive into a systems innards to address things like this. With all the constant change, it is little wonder that Cinnamon has become a standalone entity with the release of its version 2.0 and that Debian’s toyed with not going with GNOME for its latest version (7.1 at the time of writing and it picked a good GNOME Shell version in 3.4).

Having had a look at other distribution that already have GNOME Shell 3.8, I knew that a few of my extensions worked with it. The list includes Frippery Bottom Panel, Frippery Move Clock, Places Status Indicator, Removable Drive Menu, Remove Rounded Corners (not really needed with the GNOME Shell theme that I use, Elementary Luna 3.4, but I retain it anyway), Show Desktop Button, User Themes and Ignore_Request_Hide_Titlebar. Because of the changes to the backstage view, I added Frippery Applications Menu in preference to Applications Menu because I have found that to be unstable. Useful new discoveries have included Curtains Up and GNOME Shell Open Terminal while Shell Restart User Menu Entry has made a return and found a use this time around too.

There have been some extensions that were not updated to work with GNOME Shell 3.8 that I have got working. In some cases, it was as simple as updating the metadata.json file for an extension with new version numbers of 3.8 and 3.84 to the list associated with the shell version property. All extensions are to be found in the .local/share/gnome-shell/extensions location in your home directory and each has a dedicated file containing the aforementioned file.

With others, it was a matter of looking in the Looking Glass (execute lg in the box that ALT + F2 brings up on your screen to access this) and seeing what error messages were to be found in there before attempting to correct these in either the extensions’ extension.js files or whatever JavaScript (*.js) file was causing the problem. With either or both of these remedies, I managed to port the four extensions below to GNOME Shell 3.8. In fact, you can download these zip files and install them yourself to see how you get on with them.

Advanced Settings in User Menu

Antisocial Menu

Remove App Menu

Restart Shell Entry

There is a Remove Panel App Menu that works with GNOME Shell 3.8 but I found that it got rid of the Places menu instead of the panel’s App Menu so I tried porting the older extension to see if it behaved itself and it does. With these in place, I have bent Ubuntu GNOME 13.10 to my will ahead of its final release next week and that includes customising Nautilus too. Other than a new version of GNOME Shell, it looks as if it will come with less in the way of drama and a breather like that is no bad thing given that personal computing continues to remain in a state of flux these days.

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