Out of memory at line: 56

This is an error that I have started to see a lot in the last few weeks. First, it was with Piwik and latterly with WordPress.com Stats. For the record, I have never seen it on up to date systems but always with IE6 and at page unloading time. The CPU usage hits 100% before the error is produced and that has had me blaming JavaScript in error; it isn’t the cause of all ills. In fact, the cause seems to be a bug in a certain release of Adobe Flash 9 but I am of the opinion that the inclusion of certain features in a Flash movie are needed to trigger it too. I don’t have the exact details of this but WordPress.com Stats worked without fault until a recent update and that is what is making me reach the conclusion that I have. That observation is making me wonder whether we are coming to a point where Flash compatibility is something that needs to factored into the use of the said technology in a website or web application. Updating Flash will solve the problem on the client but it might be better if it wasn’t triggered on the server side either.

Ubuntu upgrades: do a clean installation or use Update Manager?

Part of some recent “fooling” brought on by the investigation of what turned out to be a duff DVD writer was a fresh installation of Ubuntu 8.10 on my main home PC. It might have brought on a certain amount of upheaval but it was nowhere near as severe as that following the same sort of thing with a Windows system. A few hours was all that was needed but the question as to whether it is better to do an upgrade every time a new Ubuntu release is unleashed on the world or to go for a complete virgin installation instead. With Ubuntu 9.04 in the offing, that question takes on a more immediate significance than it otherwise might do.

Various tricks make the whole reinstallation idea more palatable. For instance, many years of Windows usage have taught me the benefits of separating system and user files. The result is that my home directory lives on a different disk to my operating system files. Add to that the experience of being able to reuse that home drive across different Linux distros and even swapping from one distro to another becomes feasible. From various changes to my secondary machine, I can vouch that this works for Ubuntu, Fedora and Debian; the latter is what currently powers the said PC. You might have to user superuser powers to attend to ownership and access issues but the portability is certainly there and it applies anything kept on other disks too.

Naturally, there’s always the possibility of losing programs that you have had installed but losing the clutter can be liberating too. However, assembling a script made up up of one of more apt-get install commands can allow you to get many things back at a stroke. For example, I have a test web server (Apache/MySQL/PHP/Perl) set up so this would be how I’d get everything back in place before beginning further configuration. It might be no bad idea to back up your collection of software sources either; I have yet to add all of the ones that I have been using back into Synaptic. Then there are closed source packages such as VirtualBox (yes, I know that there is an open source edition) and Adobe Reader. After reinstating the former, all my virtual machines were available for me to use again without further ado. Restoring the latter allowed me to grab version 9.1 (probably more secure anyway) and it inveigles itself into Firefox now too so the number of times that I need to go through the download shuffle before seeing the contents of a PDF are much reduced, though not completely eliminated by the Windows-like ability to see a PDF loaded in a browser tab. Moving from software to hardware for a moment, it looks like any bespoke actions such as my activating an Epson Perfection 4490 Photo scanner need to be repeated but that was all that I needed to do. Getting things back into order is not so bad but you need to allow a modicum of time for this.

What I have discussed so far are what might be categorised as the common or garden aspects of a clean installation but I have seen some behaviours that make me wonder if the usual Ubuntu upgrade path is sufficiently complete in its refresh of your system. The counterpoint to all of this is that I may not have been looking for some of these things before now. That may apply to my noticing that DSLR support seems to be better with my Canon and Pentax cameras both being picked up and mounted for me as soon as they are connected to a PC, the caveat being that they are themselves powered on for this to happen. Another surprise that may be new is that the BBC iPlayer’s Listen Again works without further work from the user, a very useful development. It very clearly wasn’t that way before I carried out the invasive means. My previous tweaking might have prevented the in situ upgrade from doing its thing but I do see the point of not upsetting people’s systems with an overly aggressive update process, even if it means that some advances do not make themselves known.

So what’s my answer regarding which way to go once Ubuntu Jaunty Jackalope appears? For sake of avoiding initial disruption, I’d be inclined to go down the Update Manager route first while reserving the right to do a fresh installation later on. All in all, I am left with the gut feeling is that the jury is still out on this one.

Copying only updated and new files

With Linux/UNIX, the command line remains ever useful and allows you to do all manner of things, including file copying that only adds new files to a destination. Here’s a command that accomplishes this in Linux:

cp -urv [source] [destination]

The u switch does the update while r ensures recursion (by default, cp only copies files from a source directory and not anything sitting in subfolders) and v tells the command to tell the user what is happening.

Though buried and hardly promoted, Windows also has its command line and here’s what accomplishes a similar result:

xcopy /d /u [source] [destination]

Anything’s better than having to approve or reject every instance where source and destination files are the same or, even worse, to overwrite a file when it is not wanted.

A quick way to do an update

Here’s a quick way to get the latest updates on your PC using the command line if you are using Ubuntu or Debian:

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

Of course, you can split these commands up if you prefer to look before you leap. At the very least least, it’s so much slicker than the GUI route.