Category Archives: Techie

MSI K9MM-V & Fedora instabilities

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I have finally given up on the apalling MSI K9MM-V motherboard and Fedora 8. While tweaking BIOS and kernel options resulted in a modicum of stability, it was only briefly sustained and kernel panics frequently resurfaced during reboots.

So farewell to the K9MM-V and a welcome hello to the Gigabyte GA-MA69VM-S2. This is a more costly board but having used Gigabyte boards successfully in the past I am happy to pay a little extra for a reliable platform.

I opted for a straight board switch and connected up the same trusty Seagate Barracuda IDE drives in a RAID1 mirror configuration. The mobo swap was relatively straightforward (apart from the processor being stuck fast to the heatsink on the old board), but unfortunately no matter what combination of boot options I used the Fedora kernel just would not detect my disk drives.

After much head scratching I finally realised that the ata drivers were missing from the initrd image and so I needed to rebuild. So for those in the same bind, here’s what to do:

Boot from the Fedora install DVD into rescue mode (your partitions will be mounted under /mnt/sysimage)

chroot /mnt/sysimage

Edit /etc/modprobe.conf and add the line “options libata atapi_enabled=1”

rm -f /etc/sysconfig/hwconf

/usr/sbin/kudzu

mkinitrd -f /boot/initrd-$(uname -r).img $(uname -r)

To check the contents of your new image:

gzip -cd initrd-$(uname -r).img | cpio -id

HomePlug Powerline

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In a previous entry I bemoaned the proliferation of wireless devices and the unseen fog of wireless transmissions around the home. A new(ish) technology – HomePlug Powerline – goes some of the way to alleviate this.

HomePlug works by sending data signals around the domestic electricity ring main, much in the same way as broadband is delivered alongside your standard telephone line. The HomePlug devices act as ethernet bridges, so to attach to the network you simply plug a HomePlug device into a free mains outlet, connect up your ethernet cable and away you go.

HomePlug 1.0 specification devices provide up to 85Mbps bandwidth and are compatible with each other so you can mix and match types. The newer HomePlug AV specifications claims up to 200Mbps, although I have not tried these yet.

Since installing these devices I have been able to do away with Wi-Fi entirely, thus providing a safer electromagnetic environment and more secure network.

I recommend Solwise for their HomePlug range of products. Delivery has been next day and the products very reliable.

Silence your PC

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After a bit of trial and error I have built what I consider to be an almost silent PC server. I quickly identified that most of the noise comes from fans, these are a necessary evil to cool your PC, but there are quieter alternatives. By removing the chipset fans altogether and replacing them with larger and more efficient heatsinks, I was able to cut down noise while keeping the components adequately cooled.

I chose the quietest hard disks I could find, the Seagate Barracuda 7200.7 ST380011A. Seagate claim “idle accoustics of 2.5 bels – the industry’s best” and I do agree that they are remarkably quiet.

Next was the PSU. I initially tried a Zalman AM300B-APS “ultra-quiet” PSU but this was still too noisy for my delicate ears. Instead I opted for an Etasis EFN-300 300W 0db fanless ATX PSU. As the name implies, this has no fans at all and relies on dissipating heat through metal fins exposed at the back of the unit. I was initially concerned that the fins would run hot, but it has been surprisingly cool to the touch – and reliable!

Finally I tackled the CPU (AMD Athlon XP 2200+ 1.8GHz SoA). This is the one component that runs very hot and cannot generally be cooled by passive convection. I installed a Zalman CNPS7000B-AlCu Super Flower Cooler which has a silent mode by adjusting the fan speed using the ‘FAN MATE 2’ accessory. It is not totally silent, but at low speeds is probably as good as you could expect.

Overall, my silent PC server has been a roaring 😉 success. It has been running continuously since September 2004 and none of the modified components have showed any signs of failing. The CPU and twin Seagate disk drives run at a constant 48°C, both well within normal operating temperatures.

Suppliers:

Give me wires any day

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Is it just me or is the current obsession with wirelessly enabling everything that isn’t screwed down causing a problem when you try to get all these devices to work at the same time?

In our house we have the following wireless products:

  • 802.11g Wi-Fi (2.412GHz to 2.472GHz)
  • DigiSender AV (choice of 2.414GHz/2.432GHz/2.450GHz/2.468GHz)
  • Bluetooth mobile handsets (2.402GHz to 2.480GHz)
  • Home monitoring: 868.95MHz
  • Sky Gnome audio: (choice of 863.4MHz/863.8MHz/864.2MHz/864.6MHz)
  • Sky Gnome control channel: 433.92MHz
  • DigiSender IR relay: 433.92MHz
  • Drayton Digistat: 433.92MHz
  • OneForAll remote control extender: 418MHz

As you can see, there is a lot of radio frequency conflict in the 433MHz band (designated for Industrial, Scientific and Medical applications) and my list is far from exhaustive, not including interference from neighbouring equipment such as garage door openers, CCTV and home security.

I only succeeded in making a remote control extender work after I found an ancient OneForAll device that uses 418MHz (instead of the already cluttered 433MHz) and my video sender fails every time I use the microwave! There is now a desperate need for additional unlicensed spectrum for low-power wireless home automation devices, to provide customers with an opportunity to manage their local equipment with minimal conflicts.

It is a common debate, but what are the health risks of all this localised radio energy, not to mention the combined effect of GSM and UMTS? How long before radio based denial-of-service attacks become more prevalent? Perhaps remotely tampering with your gadgets will replace knock down ginger as the preferred domestic disturbance method for today’s disaffected youth?

Like it says in the subject, give me the safety and security of wires any day!

Talking Telephone Numbers

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It really irks me that so many businesses can’t format their London telephone numbers correctly.

The area code is 020, not 0207 or 0208 !

London numbers should be formatted like this: (020) 7946 0999

The significance of the bracketed area code is that you can omit it altogether if you are calling from within the same code area. So to call a London number from within the London code area you just need to dial the local number, e.g. 7946 0999.

Wrong: (0207) 946 0999

Right: (020) 7946 0999

Please point offenders in this direction for some education!

» Ofcom: A User’s Guide to Telephone Numbering
» Ofcom: Telephone Numbers for drama purposes