WordPress 2.6 added post revisions as a new feature that is turned on by default. In an earlier post, I described how you could control this by editing wp-config.php and there are a number of plugins that purport to provide the same level of control through the administration screens. Even so, I decided to look at things from the housekeeping side of things and create my own plugin for clearing the database of revisions at one swoop. Currently, it takes out all revisions but I am thinking of adding the facility for selecting which revision to keep and which to delete. It goes without saying that you should back up your database first in case anything might go wrong.

Download Remove Revisions 1.0

In previous posts, I have talked about getting VMware Workstation back on its feet again after a kernel upgrade. It also seems that VirtualBox is prone to the same sort of affliction. However, while VMware Workstation fails to start at all, VirtualBox at least starts itself even if it cannot get a virtual machine going and generates errors instead.

My usual course of action is to fire up Synaptic and install the drivers for the relevant kernel. Looking for virtualbox-ose-modules-[kernel version and type] and installing that usually resolves the problem. For example, at the time of writing, the latest file available for my system would be virtualbox-ose-modules-2.6.24-19-generic.  If you are a command line fan, the command for this would be:

sudo apt-get install virtualbox-ose-modules-2.6.24-19-generic

The next thing to do would be to issue the command to start the vboxdrv service and you’d be all set:

sudo /etc/init.d/vboxdrv start

There is one point of weakness (an Achilles heal, if you like) with all of this: the relevant modules need to be available in the first place and I hit a glitch after updating the kernel to 2.6.24-20 when they weren’t; I do wonder why Canonical fail to keep both in step with one another and why the new kernel modules don’t come through the updates automatically either. However, there is a way around this too. That means installing virtualbox-ose-source via either Synaptic or the command line:

sudo apt-get install virtualbox-ose-source

The subsequent steps involve issuing more commands to perform a reinstallation from the source code:

sudo m-a prepare

sudo m-a auto-install virtualbox-ose

Once these are complete, the next is to start the vbox drv as described earlier and to add yourself to vboxusers group if you’re still having trouble:

sudo adduser [your username] vboxusers

The source code installation option certainly got me up and running again and I’ll be keeping it on hand for use should the situation raise its head again.

It’s probably about time that I drew attention to Ubuntu’s The Fridge. While the strap line says “News for Human Beings”, it seems to be the place to find out about development releases of the said Linux distribution. Today, there’s a new alpha release of Intrepid Ibex (8.10) out and they have the details. As for me, I’ll stick to updating my 8.10 installation using Synaptic rather than going through the whole risky process of a complete installation following a download of the CD image. Saying that, it would be nice to see the System Monitor indicating which alpha release I have. I didn’t notice anything very dramatic after I did the update, apart maybe from the hiding away of boot messages at system startup and shutdown or the appearance of a button for changing display settings in the panel atop the desktop.

Copy and pasting between Windows programs can cause unwanted formatting to be carried over. Copying text from Internet Explorer into Outlook is one example of this that I see a lot and Word to Word does it too. A trick that I picked up for avoiding this copying of formatting comes from a while back: copying into Notepad and pasting from there. Doing the copy/paste shuffle in that way strips off the formatting baggage and alllows the default formatting for the particular destination to be applied. There may be other and slicker ways to do this but what I have described works for me.

In Windows, it’s a matter of right-clicking on the folder and looking in its properties. I am sure that there is a better way of doing it in that ever pervasive operating system but, in the worlds of Linux and UNIX, the command line comes to the rescue as it is wont to do. What follows is the command that I use:

du -sh foldername

The s option makes it present the total space taken up and leaving it out gets you a breakdown of how much space the subfolders are taking up as well. The h makes the sizes output more friendly to human eyes with things like 10K, 79M and 51G littering what you get. The command itself is a much shorter way of saying “print disk usage”. It’s all quick and easy when you know it and very useful in this age of ever increasing data volumes.

This may seem esoteric for some but I like to be in control of the technology that I use. So, when Automattic included post revision retention to WordPress 2.6, I had my reservations about how much it would clutter my database with things that I didn’t need. Thankfully, there is a way to control the feature but you won’t find the option in the administration screens (they seem to view this as an advanced setting and so don’t want to be adding clutter to the interface for the sake of something that only a few might ever use); you have to edit wp-config.php yourself to add it. Here are the lines that can be added and the effects that they have:

Code: define(’WP_POST_REVISIONS’,'0′);

Effect: turns off post revision retention

Code: define(’WP_POST_REVISIONS’,'-1′);

Effect: turns it on (the default setting)

Code: define(’WP_POST_REVISIONS’,'2′);

Effect: only retains two previous versions of a post (the number can be whatever you want so long as it’s an integer with a value more than zero).

Update (2008-07-23): There is now a plugin from Dion Hulse that does the above for you and more.

I must admit that my curiosity got the better of me when screenshots of Ubuntu’s 8.10, otherwise known as Intrepid Ibex, started to make their appearance. It is only at alpha2 stage so it’s definitely a no-no for production systems. However, it does run surprisingly smoothly even at this stage. Yes, I have seen rough edges and the biggest of them all has made me install it onto my spare PC; there is certainly tendency for systems to hang when you try running 8.10 in virtual machines, my preferred method for these kinds of explorations. Try it in VirtualBox and kernel panic messages ensue while you can log in on VMware Workstation only for the desktop never to load. Those could be major deficiencies for some but they have both been reported with the former being seen by many and the latter being flagged by my own self.

Because I was using a version with the alternate installer, the usual slickness that we expect of Ubuntu installations wasn’t apparent. I am sure that will change in time for the final release but I didn’t find it too taxing to get things going with this means. Nevertheless, I reckon that we will see the usual feel return in later development versions and very much in time for the final release. Because I was installing over the top of a previous Ubuntu installation, I didn’t want to lose everything but I needed to leave it wipe out the previous root system partition for it to continue without freezing. Because my home area is on a separate partition, there was no problem and it picked up settings like desktop backgrounds without a fuss. One thing that might annoy some is that all this takes manual intervention; you don’t get the sort of non-destructive and seamless upgrade capability that openSUSE 11 gives.

What you get when the installation is completed is a Linux desktop that won’t look too different from what we are used to using. Of course, we get the New Human theme with its tasteful chocolate tones in place of the previous default orangey browns. They need to sort out a bug (another of my reports)  where black text is being displayed on dark backgrounds on the default display of drop down menus in Firefox and maybe look into why changing the level of enhancements from Compiz Fusion messes up the display of the workspace switcher in the task bar but it’s fine apart from this.

Otherwise, it’s a case of steady as she goes with OpenOffice 2.4, Firefox 3 and so on. That may change as time goes on OpenOffice 3 looming in the horizon. For some, all this continuity is all well and good but I could foresee comments front some parts that nothing dramatic is happening and that Ubuntu cannot afford to stand still with the advances of Fedora, openSUSE, Mandriva and so on. Saying that, I personally like the continuity because it doesn’t mean that my apple cart is going to get overthrown now and again. Indeed, you could say that the whole Linux distribution market has matured very nicely with evolution being the order of the day and I suppose that Ubuntu needs to be seen to be evolving more than perhaps it has been doing.

In summary, it’s early days for Intrepid Ibex but it works well even at this stage. In fact, it is running sufficiently so that I am writing this very post in a Firefox session running on the thing.  It’ll be interesting to see how it goes from here and if any more pleasant surprises are visited upon us. After the “safety first” approach of Hardy Heron, I suppose that Canonical can feel a little more adventurous so we’ll see what comes. In the meantime, Here are a few screenshots below for your perusal:

By default, I think that Windows plants its temporary files in c:\windows\temp. In Linux or in Ubuntu at least, the equivalent area is /tmp. However,  not realising that /tmp when you shut down and start your PC could cause the silly blunder that I made today. I was doing a spot of reorganisation on my spare PC when I dumped some files in /tmp from a hard drive that I had added. I was reformatting the drive as ext3 following its NTFS former life. As part of this, I was editing fstab to automount the thing and a system restart ensued. I ended up losing whatever I put into /tmp, a very silly blunder. Luckily, I had the good sense not to put anything critical in there so nothing of consequence has been lost. Nevertheless, a lesson has been learnt: Windows allows its temporary area to pick up all kinds of clutter until you clear it while Linux clears the thing regularly. It’s amazing how Windows thinking can cause a howler when you have a lapse of concentration using a *NIX operating system, even for someone who uses the latter every day.

When making a start in the world of blogging, there are so many things to consider that you almost need a trial run first to learn the lingo. In fact, getting up to speed by using a service like that offered by Blogger or WordPress.com seems a very sensible starting point. Even so, the business is like building a house in that you only really what you are knowing after you have done the deed and made all the mistakes. That is particularly true when you go down the self-administered blog route. For starters, it’s so easy to pick the wrong domain name or hosting provider. Selecting your blogging software is the next step but that may not be so tricky; WordPress does a reasonable job and there’s always Movable Type, Expression Engine, Drupal (yes, really) or Habari.

That mention of blogging software brings me to something that I encountered recently: commenting functionality. I am coming around to the idea that this is probably something that needs to be considered up front because of the nature of blogging. After all, anyone that reads The Blog Herald regularly should be familiar with the idea of blogging conversations and that means that the technology to make it happen should be easy for visitors to use and easy for bloggers to administer. However, the two can collide. For one thing, there are a myriad of choices available to the blogger and the blight of comment spam is ever pervasive and growing.

When it comes to comment spam, it is best to realise that there are two sources of responses to a blog post: visitor comments or trackbacks (pingbacks?) from other blogs. I am of the opinion that the latter is probably the channel where most of the detritus travels and various anti-spam solutionss are on offer to curb its spread. Names from the WordPress world like Akismet, Spam Karma, Simple Trackback Validation and Bad Behaviour come to mind. The former can also be used, particularly when the unscrupulous make use of low cost labour in low cost countries, and that’s when the thorny questions of user registration and CAPTCHA’s arise. There is something to be said for not going to extremes with these and just stick with less onerous rules and filtering on the server side.

I must admit to having staggering into forcing visitors to register prior to adding a comment and then making them log in thereafter. I think that it’s for security reasons but WordPress creates a password and then sends it to the person who is registering rather than displaying on a web page. That can create another problem: what happens if the email fails to arrive? In the last week, this has happened with a visitor to my hillwalking blog and there could be a number of reasons for the non-arrival of the relevant email. One is ironic: being an automated email, it is getting stuck in the spam filters of the recipient’s mailbox and so never gets to them. It could also be a bug with WordPress itself (I have raised a ticket and am awaiting what Automattic might have to say to it) or a consequence of some setting made by a hosting provider. All of that makes it hard to track down the cause of the issue but it kicks off other thoughts as to its resolution. One is to remove the needed for registration and logging in in the first place but there are third party services that may help too. The former has turned out to be the case for this blog and it seems to be performing well enough so it is an acceptable option.

When it comes to using third party comment handling systems, what needs to be considered is how well they work with your blog. For instance, I gave Disqus a quick whirl and soon realised that I needed to update the themes for my WordPress blogs if I was to use it on an ongoing basis. Otherwise, it worked fine but I was left wondering if it would have been better to have brought it in when I started a blog rather than part way through and with comments made using the existing WordPress functionality. There’s also Intense Debate and I am almost certain that there are more like it but I’ll be sticking with what WordPress offers for now. The theme for my hillwalking blog has been modified to allow prospective commenters to get in touch with me if they are having problems. That’s is only an interim approach while I consider what the way forward will be.

Now that WordPress 2.6 is out, it is time to introduce a new version of Countrytones to the public. A few CSS tweaks have been needed to the original version after the changes that have been made to the administration interface for 2.6. Those screens still look largely the same with this release as they did before but for the styling of things like the bubble that alerts you to the availability of plugin upgrades, among other things.

Download Countrytones 1.0.1