Quick fix for KVM error on Mac OS X 10.4.9

Just a quicky discovered when compiling the latest version of TOP on my laptop. The app comiled fine (with the –with-module=macosx suffix) but trying to run it resulted in the following error:

kvm_open: /dev/mem: No such file or directory

GAH! It turns out Apple have been phasing out traditional KVM support in the Mach kernel. Fortunately this can be re-enabled by issuing the following command as root:

nvram boot-arg=”kmem=1″

And reboot – voila!

Hack your DNS for a better Interweb

We all spend time online, some more than others but there is one area of t’intertubes that is gernerally quite badly understood. DNS is the underpinning of the web. Every time you visit a page, load an image, send an email or chat via IM you are using DNS.

For such a critical part of the net pie, DNS is often neglected by your ISP. Their DNS servers will be a couple of cacky old boxes, creaking under the weight of 1,000′s of requests each minute and slowing you down. That said, there are alternatives. OpenDNS are a fantastic group of people who offer turbo charged DNS servers for free use. It’s a pretty simple task to tweak Windows (or your chosen OS) too use them. You can also configure your router (assuming you have one) so that all the computers in your house or office can benefit.

For further tweaks you can follow the steps outlined in this DNS hacking guide from Computer World. They cover OpenDNS and a few Windows changes to the DNS cache to reallly get things flying along.

Of course the ultimate geek solution would be to implement a dedicated caching DNS server such as DNSMasq and a local caching proxy like Squid. It’s easier than you think to convert an old PC or laptop to turbo charge your internet viewing.

For most people though, the DNS tweaks will be enough to heave your connection out of the doldrumsĀ  and shift you into top gear on the information super highway.

Take a moment

Radio 1 just played one of my favourite chill out tracks and in the time honoured tradition of sharing music I thought I’d upload it for those of you without the pain of “Britain’s # 1 radio station” inflicted on you daily:

As Edith Bowman so neatly put it – “Just take a moment, sit back, and … chill”

Are your sure? Yes I’m posix’tive!

That may well be the most tenuous post title I’ve ever tried to pull off.

It’s fairly well known that I’m a serious Apple convert. What a lot of people my not realise is that very little of that has anything to do with the style or even the GUI. For me, Apple ticks the boxes because it provides a stable, working platform based on BSD. This means it is one of the best OSs from which to begin Linux development and system administration.

Linux is a word that scares a lot of people. But what if I were to tell you that, up until February of last year I had never used a Linux system in anger? I now consider myself more than proficient, happy to run day to day administration, compile applications and run a dedicated web/dns/mail server. I also work in a position where the majority of my development work takes place on open source technology with the core engine running on RHEL … which is about as serious as Linux gets.

The main thing to bear in mind is this: I was able to skill up on Linux systems mainly thanks to my Mac. It handled all of the nasty, tricksy bits (3D acceleration, wireless networking, etc) whilst allowing me the opportunity to extend the OS under the hood. There are those who rave about Quicksilver being the best mac tool since sliced bread, for me it’s the terminal and the scripting languages made available there in.

Of course it’s not all roses. OS X does have some oddities that a true Linux user will find disorientating. Certain commands are missing or stuck somewhere odd. Launching scripts on startup (an equivalent to init.d) is a bit of a pain and the tool set offered out of the box is actually pretty basic. That said I’ve been able to resolve most of my issues by using MacPorts and Fink or even *gasp* compiling the missing apps myself!

With virtualization technologies such as VMWare, VirtualBox and Parallels now reaching the levels of stability and performance required for day to day usage, there really is no excuse not to give Linux a go. If you can’t afford a Mac then grab VMWare server and a pre built virtual machine and start poking about under the hood. Better yet, switch one of your machines completely and start learning by using.

Remember – Google is your friend, ask and you shall receive and keep track of lists like this one of useful commands to refer back to. It’s a lot to learn but as I’ll be pointing out in another post, you’ll be taking your first step into a larger world.