Category Archives: Linux

Building a Debian package using SCons

I wanted to do this and couldn’t find any examples, so I’ve posted some notes on how I did it.

Virtualisation

A while back I thought virtualisation technology was going to be the hot topic of 2006. Well, it was, in certain niche areas, but the momentum is still growing.

Shortly after VMware’s amazing IPO, XenSource, a spin-out from the Cambridge Computer Lab, have been bought by Citrix in a deal worth $500M. And not all of the money is virtual – there’s a good chunk of cash there too.

Many congratulations to my pals there, who will now definitely be buying the drinks next time we meet at the pub.

But this is also a nice challenge to those who don’t believe you can make money from Open Source…

Laptopia?

Not long ago, Dell announced that it was starting to ship computers with Linux installed.

Now Lenovo have followed suit. Lenovo are a large supplier of PCs, having bought IBM’s PC business a few years back.

This is encouraging stuff. Linux’s biggest handicap in the past has been that users need to install it, which put it at a big disadvantage when compared to other PC operating systems.

Ndiyo and the 940UX

Michael and I got a couple of new toys for the Ndiyo office. We took them out of the box and plugged them in, ran some of our experimental software, and they just worked.

So we decided to point a camcorder at them and make a little movie

We’re biased, of course, but we think this is quite cool.

You saw it on the CamVine

It’s an exciting time at Cambridge Visual Networks because we’re just starting to get orders from real customers.

CamVine

CamVine, as we often abbreviate it, is a new company which we’ve set up to develop some of the ideas generated around Ndiyo. We’ve been working on it since the start of the year, but it’s only been officially incorporated for about a month, so it’s very encouraging to get sales, however modest, this early on…

Watch this space…!

netrenderer

Anyone who’s done any quantity of web design knows that there are often two phases to the process. The first involves creating your design using nice, clean, standards-compliant HTML and CSS, and the second involves inserting tweaks and hacks to get around the bugs and quirks of Internet Explorer.

Most web designers tend not to use IE. This is not just because of its failings; it’s often because other browsers offer designers facilities which make the development process easier; perhaps the best example is the excellent (and free) Firebug extension for Firefox.

In addition, most people of a creative or technical bent don’t use Windows; they use platforms such as Mac or Linux where IE isn’t available. But they do need to check what the sites will look like for people still using IE. So NetRenderer is a useful service – you type in a URL, pick your version of IE, and it promptly displays the image of your page under that browser.

GRUB CD image and Error 15

This is a post for anyone who, like me, has been doing web searches to find out what might be the problem if your Linux machine displays GRUB Error 15 on booting. Or who has general GRUB issues to debug.

My problem was Error 15, which indicates that GRUB cannot find one of the files it needs. If you get it while setting up GRUB, it’s often fairly easy to find out what’s wrong. But if GRUB thinks it’s installed OK, and you then reboot, you can still get this message but without any further information to help you debug it.

To cut a long story short, the issue for me was that the BIOS (and GRUB while booting), saw my two hard disks in a different order from the way the kernel saw them after booting. So my assumptions that /dev/sda was the same as (hd0) was invalid.

Finding this out took a very long time, though, because, for reasons too complex to go into here, I was booting this server not from a regular CD but from an emulated CD the other side of the Atlantic.

Things became a lot faster when I found this section in the GRUB documentation which explained how to make a bootable CD ISO image with GRUB on it. To save you the trouble, here’s one:

I could mount this and use the GRUB console command line to find out what was wrong. It’s worth exploring the GRUB console, if you haven’t already. It can do things like filename completion when you press TAB, and can even display the contents of text files using, for example,

cat (hd0,0)/boot/grub/menu.lst

In my case I found that the BIOS of the machine allowed me to choose the boot order of the hard disks, and swapping them there was the easiest solution.

Hope this is useful to somebody!

© Copyright Quentin Stafford-Fraser