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Not Blog - Linux tutorials and articles
March 15, 2013, 07:05:34 pm by rocketnine
I'm working on my Linux skills. Right now I'm focusing on server applications as well as common sysadmin tasks.
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September 03, 2012, 11:37:31 pm by cirrus
Who cares about IPv6?
January 05, 2011, 01:03:50 am by Smither
My interest in IPv6 was first peaked a few months ago when someone on the local computer society chat room was ranting and joking about how no one's ready for IPv6. I think found this article on the society website, which made me make a note to have a look at IPv6 when I had some time.
But then yesterday I found this, and thought I'd share.
I'm about to go try that IPv6 tunnel thing right now.
The fallacy of bandwidth limits on hosting and internet connections
July 08, 2010, 09:17:56 pm by kirrus
- reposted from my main blog -
Currently, according to mainstream media, bandwidth is defined as the quantity of data you download or upload to the internet over a month. So, for example, your ISP will tell you the maximum bandwidth limit is 100GB. Or whatever.
That, however, is not it’s true definition. It’s true definition is:
a data transmission rate; the maximum amount of information (bits/second) that can be transmitted along a channel.
This is the secret thing about bandwidth. ISPs don’t care about how much you upload to the web over a given period. We care about how fast you upload it.
When you pay for a high-level connection to the internet, that you use to connect houses to, or web-serving computers, you do not pay in quantity over time. You pay in speed. So, for example, 1 gigabit per second. If you go over that speed, longer than a allowed ‘burst’ period, you pay an overage charge, always assuming that your network is even capable of going over that speed.
Think of bandwidth like gas going through a pipe. (Terrible, terrible analogy, I know. But it’s the easiest way to explain.) That gas can only flow so fast, and only so much can be fit in the pipe at any one time. We don’t particularly care if you use 100GB by taking a trickle out of the system at any one time. We do care if you take a torrent.
Realistically though, customers never notice bandwidth. They’re too busy playing with computer-resource hungry things, like wordpress, to even be able to consume all of their allocated bandwidth. Only very, very rarely do we actually start thinking about bandwidth rather than computing resources. Normally, it’s podcasts. Static file. Almost no server-resources required to send it out onto the internet. But it eats bandwidth. Most are ~50-80Megabytes per episode. You get enough people downloading that simultaneously, and we’re going to start noticing…
As long as the current trend continues, i.e. the more computing power we have available to provide you with your shiny websites, the more the people creating the shiny websites waste computing power, the mainstream will never notice this secret.
More often than not, the reason we ask people to upgrade off our shared servers, is not because they’ve reached any arbitrary bandwidth limit, although we may use this as a guide to identify them. It’s because they’re using too much CPU time.
My second ever bash script
June 25, 2010, 01:37:03 pm by Sophia
It's very studenty :p
Funny FTP-client crash
June 25, 2010, 08:39:41 am by shtromm
Normally I thought that the ftp-clients are rock-stable. Not so with Debian's Lenny for ADM64 system:
Funny - isn't it?
More interesting is that Debian has fix it for the i386-architecture ( http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=508378 ), but not for AMD64. I think i shall tell.
Desktop file sharing for people ...
May 30, 2010, 02:54:22 pm by Mad Penguin
Do you remember the good old days when you could set up drive shares between your Windows PC's and share files between machines? I do, and indeed more recently there's been all the fun of making SAMBA work between Windows and Linux so Linux PC's can also share those same files. Although not that difficult, generally it's a PITA and ultimately you just know that one day either a Windows Update or Linux distro update is going to upset the apple cart and you'll be configuring it all over again.
Still, good way to keep your skills up, eh?!
Anyway, for today's generation of "you know where you can stick your Windows box" where all you need is to share files between multiple Linux boxes, there are again a plethora of methods and invariably people will quote NFS without thinking too much. (or of course SAMBA) There are however alternatives, in particular I'm talking about SSHFS, which historically may have come across as a little obscure, but in combination with recent Gnome desktops is THE way to share files at a desktop level.
Ok, well let's assume you have SSH running on all your boxes, typically this is what you're going to have running for the purposes of remote administration. If it's not running it's usually very easy to install - on Ubuntu or Mint for example you can do it through the GUI or from the command line;
Once you have this running on a box, all you need is a username / password on the box, and everything is set up! (good eh?!)
So, to connect to a local machine on your network, in my example I'm going to use a machine with IP address 10.90.0.102 and because I never hit the wrong key, I'm going to use the root user.
What you should see then (you may have to wait a couple of seconds depending on your connection and the speed of your machines) is a file browser showing you the files available on the target machine.
What can I do with this?
You can drag and drop files between the target machine and your machine, and you can open files on this remote filesystem directly using any standard Gnome application.
Why is this really cool?
o It's works over local area networks AND over the Internet
o It's encrypted, so it's effectively a secure / VPN link
o Use the book mark option to effectively make the link persistent between reboots
o The only configuration required is listed above!
So if you need high performance file sharing and you have time on your hands, you will need to look at things like NFS, Samba (and dare I say 'gluster'). However, if you're looking for a more moderate / desktop experience without all the in depth tek, when these terms are mentioned, cover your ears and run away! These services are great, but technically complex and complete overkill!
Yeah, but Windows has "Terminal Server" !
May 23, 2010, 12:50:46 pm by Mad Penguin
One long running Windows 'feature' is 'Terminal Server', the ability to log into your computer from a remote location and run a full graphical connection over a network link. There have been many predecessors to Terminal Server over the years (for example "PCAnywhere") but at the end of the day, M$ have integrated a pretty competent protocol (RDP) into the heart of all their systems and when all's said and done, it does a pretty good job.
For historical reasons (and/or reasons unbeknown to me) the Linux community seem to have adopted VNC as it's core protocol, and indeed you will find that this is built into the Gnome desktop in an attempt to provide similar desktop sharing capabilities. Not to put too fine a point on it, compared to RDP on Windows, VNC is (IMHO) utter rubbish. 15 Years ago it would have been really ground breaking, but today, given the alternatives .. Why on earth .. ?!
When I say alternatives, I am of course talking about NX , which is effectively the Linux alternative to RDP and after having used both for many years, I don't think there is any question that NX is way out in front. (i.e. the Linux solution is much better than the Windows solution!) I know people out there will say "but it's not open source!", and once upon a time they may've been right, but not recently.
NoMachine.org do indeed sell a commercial version of the NX server and client (which is cheaper than Terminal Server), however they also provide a COMPLETELY FREE 2-user version of the software (which is slightly better licensing than the free Terminal Server you get with Windows XP!) AND the source code for NX "IS" Open Source, so you can go build it yourself.
So here's the question, why don't developers flush VNC down the toilet and take the source code to NX and build it into distro's by default? Not a desperately difficult concept, not one that would be particularly difficult to implement.
Note that although the NX Server is for Linux only, there are both Linux and Windows versions of the client, so it also makes for a really easy to introduce Windows users to a Linux desktop!
What do you mean "it's better than Firefox?!"
May 15, 2010, 11:58:19 pm by Mad Penguin
I've always been a fan of web browsers that aren't "Internet Explorer", all the way back to my first - NCSA Mosiac. Every browser has it's pro's and con's and with each new release, typically things keep getting better and faster - but at the end of the day, a browser is just a browser and there's not that much to choose from, right?
Well .. maybe, maybe not.
I first tried out Google Chrome about 6 months ago .. and I've not looked back. Whereas I'll load Firefox on occasion to access old bookmarks etc, or test a website for compatibility, Chrome is just SO much better than Firefox it really is a little embarrassing.
If you don't have it already, and want to take a look then click here.
A Domain by any other Name ...1 2  4
May 15, 2010, 01:01:29 pm by Mad Penguin
Content aside, websites are all about who visits them. If nobody visits a site then it doesn't matter how good the site is, how valuable the content is or how much effort goes into maintaining it, the value of the site in any context is zero.
SEO (Search Engine Optimisation) is a little bit of a black art, whereas the linux.co.uk domain name is well ranked and is classed as a Google PR5, the sub-domain we are using for the forums, although indexed by Google, is not recognised as a site in it's own right and seems not to be acquiring it's own Page Rank. The content on the forums is way more current and changing daily while the content on the main site is old and static .. go figure (!)
So, I've set up a new domain name for the Forums and while this does not replace the existing domain name the new one will work in parallel and I will see if I can persuade Google to use the new URL and if so, how long it takes them to decide the site is worth ranking.
Hence I'm please to announce, our new URL is http://linuxforums.org.uk
You can check out our visitor stats at http://linuxforums.org.uk/index.php?action=stats.