Flatworms are beautiful...

…when you look up close at about 100x magnification with polarized light:

Flatworm 100x Polarized
Flatworm 100x Polarized

Here they are at almost 5x life size:

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Reinstalling Mac OS X Lion is elegant but...

…if you do not have a VERY fast internet connection, this will be a huge pain. I rebooted, started the onboard OS Reinstall process and it went ahead downloading Lion… With my connection this works:

Network Graph
Network Graph

But imagine that over a 384kbps ADSL line...

Replacing a RAID drive using FakeRaid (dmraid) on Linux

I recently had a client that needed to replace a hard drive in a Linux FakeRaid RAID5 array using dmraid. The process is very unintuitive:

  1. Identify the failed drive by looking at /var/log/messages, dmesg or dmraid -r and run sudo smartctl -i /dev/sda and look at the Serial Number (change /dev/sda to the correct disk). Match this serial number to the physical disk.
  2. Replace the failed drive with a new drive matching or exceeding its capacity.
  3. In the BIOS for the FakeRaid controller, add the new drive back and ensure the controller is rebuilding the volume.
  4. Boot into the OS.
  5. run

    dmraid -a y

  6. This will activate the raid set and should start the rebuild process. In my case this did not persist after reboot, hence /dev/mapper did not show the partition table. The solution was to rebuild the initrd image:

    uname -a
    mkinitrd /boot/initrd-2.6.18-128.1.6.el5.img.NEW 2.6.18-128.1.6.el5

  7. uname -a was used to identify the correct kernel. Obviously you need to update grub with the new image. Reboot otherwise you will not see the partitions on the mapper device to mount.

For some reason the whole ext3 filesystem was corrupted. I had to recreate the filesystem and rebuild the data from scratch. Not sure if it is FakeRaid's fault, or whether I made a mistake. But it certainly did not boost my confidence in software based RAID.

Canon PowerShot SX40 HS

I recently bought my daughter a Canon PowerShot SX40 HS camera for Christmas, call it an early present. Being an amateur photographer myself, it was inevitable that going out and buying a camera - even though not for me - would not have been a trivial exercise.

If it was me, I would never have purchased this camera. Anyone with more than 3 neurons will tell you that a camera with a 35x optical zoom lens (24mm - 840mm) will show significant amounts of aberrations, and with a tiny 1/2.3" CMOS sensor noise will be a problem, as well as dynamic range and colour depth.

However, my daughter seemed to like the way the camera holds in her hands, that it felt like a "real" camera and the zoom lens appealed to her. So… I bought it. Was about $430 if I remember correctly. Quite expensive for a Christmas present...

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Great Coffee

For the longest time I used to drink coffee only when it had three tablespoons of sugar in it. I remember how incredibly sweet coffee had to be before it was drinkable. In retrospect I guess when your parents only have Ricoffy as option, that is the only way to swallow it.

When I moved out of the house I discovered Nescafe Classic. A step-up from chicory drain water, this is at least real coffee. For a long time this is what I drank, and life was good. But like so many things, we tend to be content with the known at the expense of the unknown.

Eventually I grew up a couple of years ago and started grinding my own beans, and using a Hamilton Beach coffee maker similar to this model, basically made filter coffee at the strength of Espresso with warmed milk. This was much better, but still lacking the real deal.

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