Posts Tagged ‘Linux’

Ant Building

July 6th, 2006 No comments

I think this post by Stefan Bodewig kind of sum’s up what I’m thinking about the Ant build utility.

My company started using Ant about a year ago. We use it to compile Progress 4GL code, as well as Progress Webspeed files by using the PCT extension.

When I first saw it, I didn’t like it. I decided that using XML as a form of programming language did not make sense. I have no problem with using XML to describe build rules; the problem I have is related to the way that you can specify “build target a, followed by target b”.

But having recently gone through the process of installing it and editting a build XML file, I have to say I’m very impressed! I can overlook my distaste for “programming with XML”, because the rest flows very well indeed. Plus, I can understand it much more that I can makefiles.

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Fun with VMWare, New UML Tool and IPv6

July 3rd, 2006 No comments

On Friday, I had the day off, so I decided to play with VMWare Server on a new PC that I had inherited. I’m so impressed so far, for a free product, it does so much.

I’d played with VMWare Player at home before, and within the last year at work we’ve gone VMWare crazy and now host an awful lot of our servers in VMWare images, so I’m well used to their products by now.

I’m impressed by VMWare server though. It does so much more than VMWare Player. Even allowing somebody to install the VMWare-Tools into an image makes the “upgrade” a must.

I spent Friday building some images for a project I’m about to start work on, so that I can test it on different variants of Linux and FreeBSD, as well as on the Windows machine I have. Didn’t hit a single problem with the images, and it even runs Haiku incredibly well (that’s a one up on BeOS which doesn’t work in a VM at all).

Over the rest of the weekend, I’ve also discovered an excellent UML editor for Windows, called StarUML (, which was a professionally produced product, but has now been made Open Source and Free (as in beer, I think).

I also did a little research on IPv6 which proved very helpful. I knew a little about it from a 5 minute aside in a university lecture course, but from what I’ve learnt over the weekend, a lot of thought has gone into the mechanism. The new style of development interface makes a lot more sense, seems very compatible with IPv4 and means that future version of the protocol will require fewer implementation changes! (Lets hear it for commons sense!)

So, put all those points together, and you can pretty much tell that I’m writing some kind of server, but that’s all I’m going to say!

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Building Haiku

May 19th, 2006 No comments

As I type, I have an old PC currently running BeOS 5 (which just flies!), and it’s currently downloading the current SVN checkout of Haiku.

At the same time, I’m listening to my brand new copy of the new Snow Patrol album “Eyes Open” – It’s every little bit as good as I hoped it would be, and then some more.


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Adaptive Firewalls

February 2nd, 2006 No comments

I’m thinking of building an adaptive firewall on my Linux router at home.

I’ve noticed that people are scanning the ports on the computer, and running HTTP requests to see if they can trip several known security flaws (e.g. in AwStats).

I did a little reading up on how to build an IPTables based adaptive firewall, and I’m beginning to concoct some ideas in my brain.

Basically, what I want to do, is constantly scan the requests that are made to Apache, and maybe some other server apps, and build some rules to pick out naughty behaviour. Once I’ve done that, I can get the IP address of the offender, and build a list of banned IP addresses. I’ll only want to “ban” (i.e. block at the firewall) those IPs for a set amount of time (e.g. 24 hours), but the response time of the firewall must be quick in order to catch these people in the act, and so I must rebuild my IPTables rules in reasonable time. After the 24 hours is up, I then need to clear any expired IP addresses down again whilst still keeping blocked IPs and my other firewall rules in place.

I’m therefore thinking that producing a series of scripts based around Cron is not suitable – you can’t schedule it to work more that once every minute. It could mean that I need to produce some server program (either using a UDP socket, or UNIX-type pipe) to receive IP addresses as soon as possible, and to store the data for 24 hours.

Anyone got any good suggestions?

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Quite A Productive Evening

January 11th, 2006 No comments

Last night, I had quite a productive evening.

After months of neglect underneath my desk at home, I finally managed to get around to finish building my new home server/router. I’ve got the basics working: NAT Routing, DHCP and DNS services working, something that I had had great problems with.

It’s all reading to go now, and I can provide a simple switch with my existing router/server box (currently running SuSE 7.3 because it’s too old to run anything newer!). Once it’s in place, then I can start organising some more of the other services that I use (CVS, LDAP, SAMBA, that kind of thing). My only hold back now is getting files of the old box, and getting all my client computers to switch things like outgoing mail servers to the new IP address.

I’ve also come up with a good way of making sure I back up the necessary files if I ever need to reformat the machine: Keep copies in a directory in my home directory – I have also made notes of the other processes that I have done. Makes sense I suppose!

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Somethings Still Surprise Me

October 12th, 2005 No comments

Something surprised me last night, to the point that it made me drop open my mouth, and then start laughing in amazement. This doesn’t happen very much anymore, especially when dealing with computers – even though the outcome may not be known to me, I can usually hazard a guess at the outcome, or determine an informed estimate. It’s nice to see that I’m yet to see everything this world has to offer me.

Last night I inserted a movie DVD into my MythTV media centre. I didn’t expect it work, as I had not configured anything, and I wasn’t sure whether I needed DeCSS, it runs Linux which isn’t supposed to support movie DVDs, etc, etc.

So, I went to the “Optical Discs” menu, selected “Play DVD”. It worked. Straight away. Wonderfully. Without error. I was amazed. Seriously amazed.

So it is now that I raise my hat, and pay tribute to those people who did this. You amaze me with your dedication, generousity (let’s not forget that this is all “Free” – in both senses of the word), ingenuity and talent. Bravo.

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Linux Security Issue

September 20th, 2005 No comments

This is something to think about! If I log in to Linux at the Terminal (i.e. not using SSH or Telnet or …, but literally being sat at the computer) as an ordinary user, do a bit of work, and then log out again; most of the time the screen is not cleared for the new Login prompt. Therefore, if anyone were to be able to look at the screen, they would be able to see what I had been doing.

Now to me, that seems like one hell of a security issue. Has any one else noticed this, or is it just me? Is there any reason for it, and it is me just not realising?

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This is ridiculous

March 29th, 2005 No comments

Have a look at this.

That RJ45 connector, it’s not just a connector. That’s the computer that’s running it too.

Yes, a proper computer. It runs Linux.

This is just insane….

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MythTV Box Done (Again)

March 27th, 2005 No comments

OK, the other day, I receive even more donated PC parts (including another hard disk – this time only 3.2GB but big enough to shoe-horn Linux and MythTV onto, and leave the 10GB disk for recorded videos), so I did a complete reinstall of MythTV – this time missing out the step to trying to load the correct module settings for my bttv based card (which last time knackered everything up).

I had some major pain-in-the-arse stuff trying to get the channels loaded, but eventually I managed it.

Unfortunately, the spec of the PC is way too low to be able to watch live TV on it (because of the ring-buffer based hard disk recording for pausing playback etc), but it should be OK to record programs. I did schedule one recording, which it did, but it’s got no sound when I play it back (I know now that there was no sound recorded), which is a problem that I will have to overcome before the box becomes of any use at all.

I’m also trying to set up port forwarding on my home router so that I can access the program recording from outside my network (e.g. from work, or from my mobile phone), but so far I’m not having much luck!

On another note, I thought “Hang on a minute, I could probably write a application for Windows to be able to schedule recordings from my PC. Yes, I know about MythWeb, but still….”. Anyway, just to make sure that I wasn’t treading on anyone’s toes, I googled, and found “WinMyth” which lets you schedule programmes and also view recorded programmes. I have to say though, after I installed it, I couldn’t get it to run because it appeared to bail out with a .Net run time error (it looks like it is trying to reference a Null pointer – doh!). (Also seen here)

OK, I’ve now installed MythWeb on my router as well, to ensure that I can access my box from the outside. If you try this approach though, you should really look at this post on the User forums, but also this reply. Also bear in mind that you backend will need to have the IP address that it listens on changed as well – more information on this page under the first “General” heading (and be sure to read the note underneath as well!)
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MythTV A GoGo!

March 21st, 2005 3 comments

Well, I’ve spent a semi-productive weekend turning an old PC that was donated to me into a hard disk recorder, using the wonderful MythTV package and Fedora Core 3.

It’s still not a perfect setup, as I’m currently using an old Hauppage WinTV Go card (with a bttv tuner), so the picture quality is not wonderful. The other problem I have is that although I can get TVTime, and XawTV to receive a picture, I’m not able to receive any kind of picture in MythTV – which is something that I will have to solve. Otherwise though, I can get everything else working (i.e. MythWeather, MythWeb, etc).

Once I’ve got this one up and running, I’m planning on building a much more powerful system, with at least 2 cards (probably Digital so that I can watch FreeView, and get a better picture signal), and put it in a pretty case next to the TV. I thought it would probably be best to see if I can get it running at first on some (relatively) free stuff, before I splash out serious cash on a better system.

If anybody wants, I should be able to provide some notes on how I acheived the setup, and how I got everything working.

Unfortunately, I still can’t get a picture on the damn thing. I think it could be to do with the bttv module, and I script I used to find the best settings for the driver. It asks you to add some lines to /etc/modprobe.conf and I think that is what has nailed it. Unfortunately, when I put it back to how it was, it still didn’t work. I’m coming to the conclusion that it may just be better to reformat and start again (“Build one to throw away” as Richard always says…).
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