Time saviour

Virtualisation is so damn useful. I'm currently trying to figure out why the new kernel update at work doesn't boot[1]. Thanks to VMWare, after each failed boot I can quickly revert to the previous state before the update. No messing around trying to restore the old kernel or reinstall the system [2].

posted: Mon, 30 Apr 2007 10:49 | permalink | comments

London Marathon 2007

I've just put up a few pictures from the London Marathon last weekend (click the image for more). We watched it last year because one of Susanna's friends (Lou) was running. Now that we live in SE1 the race goes right past our front door with the 12 mile mark being 100 metres down the road.

We managed to catch the elite men coming past. They move at a truly amazing pace; I can't believe they can keep that up for 42kms. Although they're probably used to it, the large number of motor vehicles bristling with equipment and media surrounding the leading pack must be at least a little distracting.

posted: Thu, 26 Apr 2007 20:23 | permalink | comments

Data on the rocks

I was asked to help a friend recently whose hard disk was dying. The system wouldn't boot anymore with the BIOS reporting disk or read errors. Ironically this starting happening the moment after my friend mentioned to his girlfriend that they should "really start doing backups".

Said friend was instructed by me to buy a new hard disk and an external hard disk enclosure and I went around armed with various Linux based rescue disks and a Windows XP install disk.

Things didn't start out well. I booted using one of the rescue disks and tried mounting the failing hard drive. The mount process hung and dmesg showed the kernel spewing out IDE related error messages at a great number of Hz. I ended up having to forcibly kill the mount process. Several more attempts failed in a similar way.

I had heard that failing hard disks can sometimes be made to work if cooled down. The theories about why this works seem flimsy (something about contracting the metal inside the drive so that components go back into alignment), but since options were limited at this stage I figured it was worth a try.

The new hard disk went into the computer and the faulty one was installed into the enclosure. I then wrapped the enclosure in several plastic bags and put it into the freezer with the cables hanging out of the door. With fingers crossed I connected the enclosure to the computer and turned everything on. This time I was able to mount the disk from the rescue disk without even a single kernel error. I couldn't believe it! I hurriedly partitioned the new drive and began copying before something went wrong.

There was a lot of data to copy (56GB). This gave plenty of time for worrying thoughts like "what if condensation occurs inside the cold drive and the electronics short out?". Fortunately all went well and every byte was recovered from the failing drive. After a bit more fiddling with boot.ini, NTFS conversion and incorrect file attributes the system was working normally again. Great!

After all this, I did some research to see if other people use this trick with success (one might question why I didn't do this research before I tried it...). It turns out that in most cases it does work. I'd love to hear a solid explanation of why...

posted: Thu, 05 Apr 2007 09:35 | permalink | comments