Tech

 

1. First we need to add the YUM repository holding the updated Xen. You will need to be logged in as root to carry out these instructions

 

wget http://www.gitco.de/linux/i386/centos/5/CentOS-GITCO.repo -O /etc/yum.repos.d/CentOS-GITCO.repo

2. Uninstall and reinstall the Virtualization group

yum groupremove Virtualization
yum update
yum clean all
yum groupinstall -y Virtualization

I was updating a CentOS OS and I noticed that one of the mirrors it chose was mirror.facebook.net so out of curiousity I put that into my browser and this came up. Does Facebook have extra bandwidth and storage they don't know what to do with?

I've been a maemo MID user for several years and when I bought my Nokia n800 I was amazed at how easy wireless networking and bluetooth were. At the time Linux was very difficult to setup in this area. Times have changed and the Maemo OS has pretty much stood still. Each successive release we got a new set of bugs and not much else. Things have gotten slightly more stable but for the most part the n800 is underpowered and the UI is aimed at desktop users but with a 4 inch screen. The new Freemantle is supposed to be a drastic change from the past and by this video it looks like it. From the beginning Nokia wasn't committed to the Linux based mobile Internet devices and put all of their resources behind the Symbian OS they own and the Linux OS always seemed more like an experiment than anything. I guess the experiment is over because they've done a ton of work on Freemantle. I've read that it's the first of the next gen Linux MID OSes but it isn't the final one. Freemantle will have a GTK gui and the next one after that will be QT which Nokia now owns. The one improvement that I think they need is to stabalize the software. I don't know if a Communist/Apple approach is best but you have to admit that iphone apps generally work and maemo apps don't. Anyway check out the video.

It looks like the Freemantle version of maemo that the new n900 is using is much nicer and more finger friendly than the Diablo that I'm running on my n800. As much as I like Linux I've always thought that the Bora/Chinook/Diablo line of the Maemo OS were very crude and not always stable. It's funny that when I got my n800 I thought it had the slickest wifi and bluetooth configuration of any Linux OS but now times have marched on and my frequent lockups and applications that don't work have gotten on my nerves. Granted I'm using my n800 for way more than what it was designed for. Also Nokia has never been serious about the Maemo devices. It's largely been a community run project with Nokia making the hardware. The freemantle OS and n900 seem to be a break from that trend. I predict (and you can quote me) that at some point Nokia will be making more Linux devices than Symbian.

I've been pondering a smart phone since they've been getting better and it's not because I want a phone but I want a MID (Mobile Internet Device) that connects everywhere so I have constant connectivity to IM, email, web etc.. With the n800 you have to be near an open wifi access point which gets irritating to say the least. Using DNS tunnelling you can connect through many access points that are open but require monthly fees but since AT&T opened their access points at Starbucks and Barnes & Noble this is less useful. I was really excited about the n810 wimax edition but Nokia pulled it because of a lack of wimax network. Now I see Sprint advertising 4G with their Palm Pre which is wimax. We still don't have access in the Seattle area although it's coming. So I've narrowed my choice down to an Android phone (not the G1) the Palm Pre or Nokia's new MID/Phone the n900.

To be honest the Maemo OS on the n800 isn't that great but it gets the job done. It can be unstable, the apps are amateurish and it needs to be reloaded every so often so I wasn't that excited about the n900 but it seems that Nokia has actually gotten serious about Maemo. The screenshots look wonderful and it looks like they've decided to actually make an interface for a small device instead of a tiny computer Desktop.

 

When I'm in an airport for work I have my work laptop which has a 3G cell modem and I can connect to the internet fine (sort of thanks to poor 3G coverage). This is a great thing and allows me to become "untethered" from wifi hotspots. However if I'm not lugging my laptop around I'll have my nokia n800 on me which only has wifi. I was really excited about the n810 WiMax edition because that would allow me to have internet access in metropolitan areas but unfortunately WiMax rollout was way too slow and Nokia figured their next device the n900 would be released before people could connect with the n810 WiMax edition so they pulled it. Some time later I think this was a wise decision because WiMax still isn't available outside a limited area of the US and there are problems in the way it works with treating it as a mobile service. The Nokia n900 just got submitted to the FCC so I figure by Christmas it will be out with wifi, smaller size and 3G access. However if you have a device like an n800/n810, ipod touch, laptop or any other Mobile Internet Device that relies on wifi then the MiFi may be of use to you.

Introducing the MiFi series of mobile wifi hotspots. They come in several flavors (EVDO, HSPDA US, HSPDA EU) but all work the same way. They connect to the 3G network and act as a wifi router for wireless devices. You can only connect 5 wireless devices to it at a time but considering the intended audience I don't think that's a problem. It's so small too that you can just place it in your shirt pocket and become a mobile hotspot yourself. I was just thinking how fun this would be to walk up to someone with a laptop and let them connect to the access point but then slowly move away to see if they would start to point their laptop in different areas to get a better signal.  The real fun part would be getting them to move closer to you as they figure out which direction the signal is coming from. If you were bored you could lead them around all afternoon.

Enough of my demented mind. Here's the skinny..

 

This was shown in Linux Journal 2 years ago but I just ran across it a second time. I think this is a very cool use of a very cool device. The Nokia n800 has a decent cpu, a decent screen and a webcam built in so why not use it works great as a robot head.

 

[youtube:http://www.youtube.com/watch?v=mkV4kMBUVjw 400 283]

 

It seems every day some company is announcing an Electric Vehicle. The Tesla roadster has been out a while but is a very special purpose vehicle. I've driven it and it's nice but you're not taking a trip in it any time soon. Maybe you'd commute in it but probably not. More practical EVs are coming out from many companies including Tesla's own Model S sedan. The problem I see with ALL plugin EVs is the recharge time makes them impractical. I see this problem going away in the future but currently charging your EV off your home electrical plug is going to take 2 days! Drive for 3 hrs, charge for 2 days. I don't think that's realistic. By using a 240v line you can get the charging down to one day. That means if you want to go anywhere very far away you drive for 200 miles and then you rent a motel - repeat as necessary. It would take you two weeks to get across the country. Renault of France announced a new EV and they have the advantage of being from a country that takes these things serious with some of the best mass transit (electric) in the world. The press release for the Renault Kango be Bop Z.E. shows that recharge times are about 30 minutes and range is 100 miles. So range is a bit short but I'd not drive this little car across the country anyway so maybe it's fine. The recharge times are so fast (@ 400V) that if you depleted your battery you could stop at a cafe and enjoy your cafe au lait while your car recharges.

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If you're moving from a real server installation to a VirtualBox virtualized configuration you may want to take your real physical disk and just turn it into a virtual disk. There are advantages to creating a new disk and rsyncing your OS into it but this tutorial will show you how to make an exact copy of it. Note the exact copy will be the same size as the real physical disk so make sure you have enough drive space. This is most useful for Operating System images with shared storage for data. I wouldn't advise anyone to make a 1TB copy of their new drive and turn it into a VDI file!

To get the image from the disk use the dd command.

1. dd if=/dev/hda of=./hda.img
2. VBoxManage convertdd hda.img hda.vdi

grant@workstation:~$ dd if=/dev/hda of=./hda.img

grant@workstation:~$ VBoxManage convertdd hda.img hda.vdi
VirtualBox Command Line Management Interface Version 1.6.0
(C) 2005-2008 Sun Microsystems, Inc.
All rights reserved.

Converting VDI: from DD image file="hda.img" to file="hda.vdi"...
Creating fixed image with size 1024966656 bytes (978MB)...

This will make an exact copy of /dev/hda to the raw image file hda.img. Then VBoxManage will convert the raw disk hda.img to hda.vdi for use with VirtualBox.