Dec

30

Simple Java Configuration Files and no XML in Sight

Filed Under Computers & Tech on December 30, 2006 | 55 Comments

The last time I discussed Java configuration files it was from the point of locating them on the disk the right way. This time I want to comment on the content of configuration files. There seems to be an obsession with XML in the modern world. Some people seem to think that shoe-horning XML into their applications will somehow magically make them great. I don’t want to completely put down XML because it most certainly has its uses. In fact I use it quite a bit to store complex and potentially incomplete data sets. However, using XML to store simple configuration information is over-kill and makes the configuration file needlessly complex to edit and needlessly complicates your application. Unless you’re writing something huge or some thing complex the chances are you’re configuration file won’t need to be complicated. The chances are all you really need are some name-value pairs to specify a few parameters. If this is the case Java comes with a wonderfully simple solution right out of the box, .properties files.

[tags]Java, XML, Configuration Files[/tags]

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Dec

27

Reflections on Joe’s Early Christmas Present – the Harry Potter 7 Title

Filed Under 42 (Life the Universe & Everything) on December 27, 2006 | 1 Comment

For those of you on another planet JK Rowling released the title for the seventh Harry Potter book on Friday the 22nd of December. The title is:

Harry Potter and the Deathly Hallows

I’ve given myself a few days to mull this one over and see what the Potter fandom are making of it before committing my thoughts to electrons. I have no doubt I’ll look like a fool when the book comes out and I’m shown to be totally wrong but on the off chance that I actually have it right I’d like to have it on record so I can gloat properly 🙂

[tags]Harry Potter, Deathly Hallows, Book 7, JK Rowling[/tags]

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Dec

24

If You Can’t Out-Perform them, out -Innovate Them!

Filed Under Computers & Tech on December 24, 2006 | 2 Comments

So far in my life I’ve witnessed the tail end of one real revolution in the way humans interact with computers (HCI), the introduction of the mouse into every-day computing. Sure, the mouse was invented before I was even born, but it didn’t really take off till a few years after I first started using PCs, when Windows became the dominant OS. I can remember, just, being a computer user in the days when the keyboard was your only input device. I remember moving to Windows and discovering the mouse. There have been a few occasions since when I thought I was seeing the start of another HCI revolution but none of them ever really worked out. The touch-screen has had a minimal impact but it hasn’t really taken off. Perhaps it will some day, probably when the multi-sense variety become common, but not yet. However, this week I got to use a computer in a whole new way, using a device that is, as we speak, winging it’s way to countless millions of homes. I am of course talking about the Nintendo Wii, or more specifically, its controller.

[tags]Wii, Nintendo, HCI[/tags]

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Dec

22

Rogue DHCP Detection Plugin for Nagios on RedHat

Filed Under My Projects, Security, Software Development, Computers & Tech on December 22, 2006 | 9 Comments

I’m pretty sure this is useless on most versions of Linux because the default DHCP plugin that comes with the Nagios Plugins distribution has this functionality and seems to work just fine everywhere except on RedHat-based distros like RHEL, Centos and Fedora Core. On these systems the default plugin does not seem to work and fails to detect any DHCP servers. This plugin is different to the one I gave instructions for before which tests whether a particular DHCP server is answering requests, this plugin finds rogue servers, it will not alert you if any of your actual DHCP servers are down. Hence, you should probably install both. This plugin is not very polished, it is rough and ready but I know it works on RHEL4. If you’re running a different system you may have to do some minor tweaks but this should serve as an excellent starting point none-the-less.

[tags]Nagios, DHCP, RedHat, RHEL, CentOS, Fedora, Linux[/tags]

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Dec

21

Some Silliness for the Silly-Season

Filed Under Computers & Tech on December 21, 2006 | 2 Comments

If you’re the serious kind who wouldn’t dream of wasting their precious CPU cycles on pointless fluff or if you can’t stand kitsch then you should probably just stop reading now, this won’t be of any interest to you what so ever. If you on the other hand, you have an over-abundance of festive spirit and some spare CPU cyles (and you run OS X) then MacLampX is just the thing for you.

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Dec

20

Problems Detecting Rogue DHCP Servers on Linux, not on Windows

Filed Under Computers & Tech on December 20, 2006 | 7 Comments

I am by no means shy about pointing out problems with Windows on this blog but I do try to be objective in my criticism. Today I have the rare pleasure of sharing a Windows command-line tool that I haven’t been able to find an equal to on RedHat Enterprise Linux (RHEL) 4. A few weeks ago a rogue DHCP server caused us some serious problems at work so I was asked to find a simple tool for detecting rogue servers. In theory there are loads of tools for this on Linux but after having tried everything Google was able to find for me (an entire day’s work) I’d still drawn a blank. Everything I tried insisted that our main DHCP server did not exist. What’s more tcpdump showed responses from the DHCP server arriving at the machine but all the tools insisted they got no reply regardless. In my search I did come across dhcploc.exe, a small MicroSoft command-line tool that ships with most versions of Windows. Granted, it’s not part of the default install but it is on the CD none the less and more importantly it works!

[tags]Windows, RedHat, RHEL, DHCP, Rogue DHCP Servers[/tags]

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