25 November, 2008

Low power consumption appliance based on desktop computer

I would like to have an always on server for my home network, and altrough I have already two ARM based routers which can be customized, I would like to have an x86 based computer, because it is much easier to install linux programs on it and normally they have faster processors and more memory than the ARM counterparts.

I would like to use it for 3 functions:
  1. To be the center of the home network with an Apache based WEB interface, whcih can do all network related tasks
  2. Install an Asterisk PBX and connect all our phones to it, including mobile phones via Bluetooth
  3. Be a storage backup server with two Tbyte or close to Tbyte SATA hard disks
Earlier I had a 3G/HSDPA WLAN gateway created from an old laptop, and with the HDD and display switched off, it consumed only 10W, but I was considering to have a modern desktop motherboard with a Intel E2160 or simmilar processor to reach a good power consumption.
Before going into this I checked the power consumption of different solutions on the internet and it turned out that even with an Atom processor based desktop solution it is very difficult to go below 30 W which is not acceptable for my purpose.
Here are the figures I have found:
Gigabyte GA-MA74GM-S2 with AMD processor - 31W - laptop HDD
Atom 230 single core - 27W - with laptop HDD
Atom 330 dual core - 41W - with desktop HDD
Gigabyte G33M-DS2R with Intel E2140 underclocked 40W - ??? HDD
So the conclution is that even the very low consumption of the Atom processor itself is nut visible on a complete system, as other components determine the total power consumption of the whole system.
When exploring this I found a very good site about building mini PCs here.
And found a far east company with a big selection of complete mini PCs on amazing prices here.

21 November, 2008

Upgrading Ericsson W25 to firmware 11B

After long monthes of perfect working, last week my internet connection trough the W25 started to become very unstable, most of the time even not working.
Looking at the statistics it turned out that something hapened in the network, which increased the speed of my connection :-), but after approximately one day, the connection became unstable and was more down that working.

My first guess was, that my operator has upgraded the serving cell from 3,6 Mbps to 7,2 and the 7D firmware I was using may have a bit buggy radio module. So I started the upgrade.
First I have upgraded to 11A, because I have downloaded that already before, and with the bad connection I could not check if there is a better FW available. The upgrade from the WEB UI went pretty smothly, after waiting a lot for checking the radio module FW version, the procedure ended without any problem. I was a bit afraid, that my root password will be changed, but the upgrade behaved correctly and did not change my credientials.
After logging in and trying to test the connection speed, it turned out the wget was removed from the firmware :-( This meant, that from my customizations, DynDNS, speed measurement and daily stock reports in SMS wont work any more. This would have been a pitty, but read on, the problem is fixed by now.
Nexy day I read on the W25 site that there is a 11B realease and from the release notes it looked, that there are a lot of bug fixes and a new radio ROM, so I have upgraded to the new version as well.
This upgrade went smoothly as well, the only thing was was a bit alerting, that it did not wrote anything about the radio firmware upgrade and on the end of the upgrade a new window camu up with a simple "null" text in it. But after restarting everything was ok, both the base and the radio firmware was ok.
Fixing wget
For this I went for the easiest solution I simply copied the wget file from an older firmware version I think it was a 4 or 6 series FW, but it ran without problems on the new version. So I copied it to /root and updated the custom scripts to use it. This fixed all my custom script problems.
Fixing internet problems
It seemed that the new FW did not solve the internet instability problem and from the measurements it looked like the EC/IO value is very fluctuating with this station, so I turned over my external antenna to another station and it seems that this solved the problem. What is a pity, that with the old station after the speed increase I hav speed over 2,5M, with this one I have speeds between 1,5-1,8 M, but this speed is pretty good for a lot of uses and is better to have a stable lover speed connection that a copletely unstable fast connection.
Here is the effect of changing the station: