I just spotted via kernelplanet that Greg Kroah-Hartman has released a new book, Linux Kernel in a Nutshell. Sounds like an interesting book, particularly as it’s freely available on-line too. I’ll probably end up buying a copy if I like the look of the on-line version, I hate reading from a computer screen. Worth checking out if you’re interested in the Linux kernel.
Archive for the 'Tech' Category
Bloody spam. Since moving my site to a new host I’ve had a bucketful of spam comments come through. I suspect this is because the new IP range I’m on is considerably more active than the previous one. Anyway, I’ve installed Spam Karma and hopefully that will fix the problem.
If you have any problems sending a comment please let me know via e-mail or Jabber, my contact details are here.
VMWare Workstation, the only commercial product I own, has once again proved its worth. I needed to upgrade a server today, an old Redhat box, to a proper distribution, Debian. 
Looking at the setup, I found that it had been setup using LVM, something that Redhat made stupidly easy to do in Redhat 8 with their reliable Anaconda installer. As the server is fairly mission critical I decided to try LVM on Debian inside a vmware VM. I was stunned by how far LVM has progressed since I last looked at it (LVM1 on 2.4 kernels.) Using LVM2 on a modern 2.6 kernel, it can reliably manage volumes and even resize them on-line without the need for unmounting. Another killer feature is the ability to snapshot a filesystem, something that until recently was marked as unstable on 2.6 kernels. This works like a charm. You simply issue a command to create a new logical volume based on a snapshot of a running filesystem and you instantly have a copy of the filesystem as it was at that point in time, ready for mounting. The snapshot facility uses a technology that only records changes, somewhat akin to hard link backups from how I understand it that results in a very low overhead. The documentation suggests that this can be used to create (nearly) identical filesystems for Xen, something I’m very interested in. Clever stuff. Anyone interested in LVM should have a look at the excellent LVM HowTo.
Following a little power dip yesterday, connecting all the servers to our new super APC Symmetra UPS has become a high priority. So I was a little disappointed when I started to setup the PowerChute software on the Linux servers. It appears to require that you have a GUI installed in order to use the software. Now, maybe it’s just me, but why on earth would you want a GUI on a server? None of our Linux servers have GUIs making it seemingly impossible for us to use the PowerChute software. I’ve filed a support request with APC, fingers crossed they’ll pull something out the bag..
Finally, my omahns-home box that used to host my site is now going to the skip. I think the previously mentioned fan failure has taken it’s toll on the poor Cyrix CPU as it keeps oopsing with very odd messages. Therefore i’m now using a Bytemark VM, although it appears to be struggling a little with only 64Megs RAM to play with. Hopefully I’ll get this solved in the near future. I would highly recommend Bytemark, I have two servers with them now and the support has been absolutely excellent. (I had an issue with quotas not working that Pete from Bytemark managed to track down to a missing dependency in the Debian package.) So if you’re still using the old address, http://omahns-home.bishopb-college.ac.uk, please update to the new address, http://omahns.homelinux.org
Just returned from LugRadio Live. It was superb, especially getting to meet everyone i’ve known through the IRC channel and the forums. The talk by Mark Shuttleworth was absolutely fascinating and i’m already looking forward to next years event. Now, Goodwood Festival of Speed!
Here’s my essentials.
- BugMeNot - Completes login forms to various sites that require registration, saves you the hassle of having to register yourself. Covers just about all the news sites that I visit on a regular basis.
- FlashBlock - I hate Flash with a passion. Maybe it’s because my works site is a Flash monster. This plugin prevents Flash movies from automatically playing, instead it displays a little ‘f’ icon for you to click on to play the file. As a result, it blocks many pop-up flash adverts too.
- Foxyliciuos - Integrates your social bookmarks hosted by del.icio.us into the browser. I would strongly recommend anyone living under a rock to check out del.icio.us, it’s a superb facility.
- Bloglines notifier - Adds a small notification icon to alert you when your blog subscriptions hosted by BlogLines are updated. Again, Bloglines is a superb facility. It lets you view your feeds from any browser, any where.
- LiveLines - Lets you click that RSS icon in FireFox and add feeds directly into a web blog facility of your choice, in my case Bloglines. Has many other features too.
What’s your favourite Mozilla FireFox extensions?
Seems that the box hosting my blog, omahns-home, had a bit of a fan failure causing kernel panics every few minutes. Thankfully it’s repaired now with a new heatsink/fan, so this Cyrix300 will live to burn again.
I posed the question, how ‘mere mortals of the world cope with spyware‘ to the #lugradio chat room this afternoon. Within a virtual second PerfDave replied, ‘They let it slow their computer to a crawl and then they buy a new one. Duh.‘
Unfortunately this is completely accurate. This month alone i’ve repaired 3 machines that had become unusable due to spyware (and the odd trojan here and their for good measure.) More suprising is that the owners of said machines were not computer novices that click every attachment here their and everywhere. In fact, one is an IT tutor at the college, another my Mum, who is by no means an IT newbie. Now, if only they had all taken my advice (given a good 6 months ago) to use FireFox, would they be in the same posisition that they’re in now with crippled machines..? Suprisingly all 3 machines also took a little more than usual to remove all the offending critters. Normally I would just run some spyware removal programs (currently MS Anti-Spyware, SpyBot & AdAware) followed by a full virus scan. However i’ve found recently that this often leaves stuff behind and the whole process has to be repeated in safe mode to ensure a good clean. I wonder if this is the predicted ‘kernel’ level Spyware that this article talks about.. Scary..
A story popped up on KernelTrap this morning regarding BitMover dropping the free version of their source control product, BitKeeper. BitKeeper is the ‘chosen’ product for source control of the Linux kernel. It has proved hugely controversial as it’s ‘free as in beer’ and not ‘free as in freedom’, basically meaning your rights to use the product are limited. In particular, if you use the BitKeeper product you are not allowed to develop a competing product. Sounds a bit like some Microsoft banning reviews in some of their EULAs.
I would just like to make a couple of comments with regard to the comments in the story linked above. Firstly, Larry McVoy states that
“we represent as open-source friendly a commercial organization as you are *ever* going to see”
This is simply not true. If anything, BitMover is hurting Open Source by preventing development of (better?) open-source source control products and forcing users to use their closed-source offering if they want all the features of the Linux kernel tree. Secondly..
… At some point the open source world needs to either decide they’ll tolerate commercial software and respect the fact that commercial companies are entitled to make money off their efforts or step up and take on the challenge of providing open source versions of *every* application.”
IMHO the Open Source community is already working on open source versions of every application. I cannot think of a single application that exists commercially where there isn’t already an effort to produce an open source version. Can anyone else?
Our existing phone system at work uses two big Meridian (now Nortel I believe) switches. I have very little idea how it works as we have an excellent phone guy, Alan, that does all the hard work. What I do know is that it uses a green screen dumb terminal and very cryptic (assembly looking) language. Nasty. Thats not the main problem though. The main problem with our Meridian switch is that its full, or very nearly full and so we’re unable to add more extensions on to the system. The end result is that we’ve started looking at Voice over IP (VoIP) solutions. One such solution is Asterisk. From the homepage:
Asterisk is a complete PBX in software. It runs on Linux and provides all of the features you would expect from a PBX and more. Asterisk does voice over IP in three protocols, and can interoperate with almost all standards-based telephony equipment using relatively inexpensive hardware.
Asterisk provides Voicemail services with Directory, Call Conferencing, Interactive Voice Response, Call Queuing. It has support for three-way calling, caller ID services, ADSI, SIP and H.323 (as both client and gateway). Check the Features section for a more complete list.
Sounds nice. I also spotted this blog about using Asterisk at home. I’m very tempted to give it a try although the usual restrictions will be imposed by partner, kittens, etc. 
I would be cautious however about using Asterisk on a greater scale at work. We currently have about 30 outgoing PSTN lines and around 300 extensions. I’ll be spending some time looking for case studies on a similar scale roll out to try and learn from their experience. In the mean time, has anyone given Asterisk a try themselves? I would be very interested to hear how you’ve found the package..
I’ve finally found the time, while SWMBO is sleeping, to switch my blog over to WordPress. WordPress looks very comprehensive, compared to the bblog tool that I tried originally and i’m hoping to make more use of my blog now its easier to make formatted posts. I’ve felt more and more guilty as time has passed regarding the amount that i’m learning from reading other users blogs, yet I haven’t really given anything back to the community. This will be changing now as i’m determined to blog more about what i’ve learned. Whether it will be of any use to anyone is another matter.
