Today I replaced the sidelights in my car with white LEDs. I was annoyed by the very yellow tinge of the traditional 501 (aka W5W) bulbs.
The new LEDs produce a very narrow beam and don’t illuminate the reflector as the bulbs used to. I like it.
I promise to upload more photos in a more glamorous location than a car park, and when I’ve had a chance to wash the car!
If you liked my Big photo, perhaps you’d like to see how it was done. Not as hard as you might think! You will need:
I lit the scene using natural sunlight from the window to illuminate the sheet. This makes it look more like sky. I also used the modelling light on my flash – but not the flash itself – to light the scene from the sun. I positioned the flash where the sun might be above my little city.
The final image that I published was exactly as it came from the camera – no editing whatsoever, not even a crop.
From Stu: Back to the usual rules, this week you’re taking a picture especially for the challenge. And the theme is BIG. Good luck!
Well, I haven’t put so much effort into a photograph for a long time! I had fun with this one – cutting out, painting and making a mess. If you want to see how I did it, see The Making Of.
Not quite King Kong, not quite Transformers – but reminds me of Pinocchio on steroids or something.
While pondering ideas for Stu’s “big”-themed photo challenge this week, I vaguely recalled taking a picture of my younger brother Edmund some years ago where I managed to make him look big.
Eventually I found the photo (a 6″x4″ print from a disposable camera) and pinned the date down as 1998, when I would have been 12, and he just 4.
Note: This article is under development. More info and screenshots will be added later. Keep checking back!
I decided to buy a mobile broadband USB modem yesterday. For those of you who don’t know, I work as a wireless network & VPN specialist for the University of Bristol. At the time of writing, there are 507 access points around campus, giving pretty good coverage. However I often have to visit locations with dead wireless to fix it – and it’s times like these that mobile broadband would come in really handy.
After a bit of market research, I found that Three was the cheapest network; however their standard issue USB modem is made by ZTE and some Googling shows that this isn’t well supported by Linux. That’s a showstopper for me. However, O2 offer Huawei modems which, according to the Internet, work out of the box with recent versions of NetworkManager, which is included with distros such as Fedora and Ubuntu.
After a quick word with an O2 sales adviser, I was told that Windows and OS X are supported, and Linux is not only unsupported, but “won’t work”. Of course, I took this with a pinch of salt. I prefer to believe articles on FedoraForum, for example.
I run a number of operating systems on my various computers. It’s not essential to have it working on all of them, but it would be nice. Here’s what I’ve got:
So how did O2 Mobile Broadband really fare on these various systems?
First I tried it with the computer I am likely to use most on the move – my trusty EeePC. I connected the modem and was immediately greeted with a screen saying it had detected a USB modem.
I was asked to pick a network provider from a short list.
Setup was complete!
I now connect by using the NetworkManager list, the same way as for regular wireless networks. However, even if I connect to O2 Mobile Broadband, it still uses wireless networks in preference if possible. Very sensible!
Fedora runs a very similar version of NetworkManager to Ubuntu. The main difference is that you don’t get a magic wizard to put the settings in for you. But don’t worry, it’s quite simple.
Getting it to work on Windows was easy, although I was not impressed by the software. When you plug in the USB modem, it automatically mounts as a virtual CD-ROM which then autoruns the installer. It’s all themed in the O2 colours and looks smart, even if horrible and blue. Installing it is a simple case of clicking Next repeatedly.
But what I didn’t like was the way that the software automatically takes control of your wired and wireless connections too, without consent.
In its defence, it does work and it does do the job. It even has nice features, such as being able to prioritise various connections or networks. You can say you want the wired to always take precedence, followed by your home wireless network, then the 3G network, and finally your neighbour’s wireless.
However, the application is ugly, blue and blobby. It looks like a UFO. It installed yet another tray icon I don’t want, and it’s changed the way I connect to wireless networks. Of course I’m capable of adapting to the change, but I liked the way I connected to networks before. Why force me to change?
One thing I haven’t tested yet is its ability to connect to WPA2-Enterprise (802.1x) networks, which I use daily as part of my job. This is where lots of other third-party wireless applications fall down.
Tonight I will look into ways to remove the app but keep the driver – and perhaps have the 3G connection available to me as an on-demand connection, the same way that Windows handles VPN connections.
Overall, I’m glad I will almost never be using this laptop with my 3G connection.
Despite Apple Macs having a reputation for being intuitive and easy to use, installing the USB modem was a nightmare and I still haven’t got it to work.
While Windows and OS X are the two officially supported platforms, the OS X software is just the default Huawei software without any O2 theming at all. O2 haven’t even bothered to bap in the config in advance. Plugging in the USB modem causes a directory to be mounted, containing an installer and a PDF document. The PDF briefly explains how to install the application and fill in the settings. It has a series of screenshots and simple instructions, although still daunting enough compared with the ease by which most Mac applications are installed.
The software itself is ugly and a bit clunky. It doesn’t have anything sensible like a “tray” icon. You have to load the application manually before you want to use the connection. If you frequently use the software, it would be best to make a dock icon, which you also have to do manually.
Worst of all, it doesn’t actually work (for me). I followed the guide exactly and yet when I came to connect, it always fails with a useless error message of “Connection failure!”.
This evening I decided to take a stroll along the canal near Atherstone with my parents, brother Edmund and girlfriend Hana. It was a really nice evening for a walk and we covered about three miles.
I think I may have stumbled across a security problem in OS X on my Macbook. To recreate it, you need to satisfy the following conditions:
I spotted this bug accidentally on my Mac when I was a bit hasty typing in my unlock password, and was shocked to see it appear in the 802.1x username box after I unlocked successfully.
I’m using Leopard, 10.5.7. I’d be very interested to hear from anyone who can recreate this bug on other versions of the OS.
I’d be ever more interested to hear from anyone who figures out how to enter keystrokes through a lock screen to an arbitrary application. I’ve tried this, and Control+Tab doesn’t work, so you can’t immediately switch to other windows. I’ve also tried successfully entering my 802.1x credentials through the lock screen to dismiss the 802.1x box, but after that my keystrokes are not accepted.
In this article I will talk you through how to set up automatic backups from your Linux computer, to another Linux/Unix computer of some description. This works for OS X, too. I have tested these instructions on Fedora and Ubuntu.
These backups will use rsync, a handy program for copying only the files that have changed. The first backup will obviously copy all of your stuff, but after then if you only create/change one text file, it only copies one text file.
Your receiving computer (let’s call it the server) needs to be running an SSH server. This is standard on almost every Linux/Unix/OS X computer. If not, consult your OS documentation for guidance on how make it go. Don’t forget you need to poke a hole in your firewall (port 22/tcp) as well as setting up the SSH server.
Your sending computer (the client) needs to be set up with a private/public key pair. This is so it can communicate with the server without having to ask for a password. First check if you have keys by doing the following:
jonathan@hyperion:~$ ls ~/.ssh
If this command results in displaying the files id_rsa and id_rsa.pub then you are all set. Skip ahead to the step about copying the key to the server.. If those files or that directory don’t exist then you’ll need to create them, like so:
jonathan@hyperion:~$ ssh-keygen
Accept the default options and it will create a private/public key pair for you. Now we set permissions on your keys to keep them secure, and to ensure that the key authentication works properly:
jonathan@hyperion:~$ chmod 600 ~/.ssh
jonathan@hyperion:~$ chmod 600 ~/.ssh/id_rsa*
Copy the public key (identified by its .pub extension) to the server. Don’t whatever you do copy the private key to any other computer. You should treat the private key as securely as your password Copying is easiest using scp, but you can use a USB memory stick, email attachment or any other method of copying data.
jonathan@hyperion:~$ scp ~/.ssh/id_rsa.pub jonathan@server.com:~
Now you need to log onto the server and tell it to trust your key. Be doubly sure to use a double >>, otherwise you will overwrite the authorized_keys file rather than appending to it.
jonathan@server:~$ cat id_rsa.pub >> .ssh/authorized_keys
jonathan@server:~$ chmod 600 ~/.ssh/authorized_keys
Your key authentication should now be fully set up. You can test it by connection to the server from the client using ssh – if the key authentication is set up properly you will get automatically logged in without being asked for a password.
Consider what you actually want to back up. Most likely just your home directory, i.e. /home/jonathan. Also think about where the backups will be stored on the server. If this is your home directory again, then no problem. If you wanted to store it in a different directory, you would probably need to grant write access to that directory to your user account.
In this article, we will assume that I want to back up /home/jonathan on my client to /media/private/Backup/hyperion on the server. So let’s make a script to do this. Call it backup.sh and save it in your home directory. Change the paths, usernames and server name in this example to suit your setup. You can also use an IP address instead of a server name if you don’t have DNS running on your LAN.
#!/bin/sh
rsync -rutvz --delete --exclude=".*" /home/jonathan jonathan@server.example.com:/media/private/Backup/
Note: the line starting with rsync is one long line – don’t put a linebreak in
Note: this excludes hidden files (ones starting with a dot, such as .test). If this is not what you want, remove --exclude=".*" from the rsync line.
Set it as executable, and run it for the first time
jonathan@hyperion:~$ chmod +x backup.sh
jonathan@hyperion:~$ ./backup.sh
Depending on the size of your home folder, the first run could take ages. I strongly recommend having a gigabit LAN in your home for copying large amounts of data. After it has completed, check on the server that your files have indeed made it across to the place you intended.
Now run it again. It should take only a few seconds to run, as no files have changed since you last ran the script.
Create a text file in your home directory with a few words on it. Run your script again. Check the new file got copied to the server.
Delete the text file from your home directory. Run your script again. Check the the file got deleted from the server.
If your server and client are on the same LAN, the server is always on, and it’s a fast LAN, the best option will probably be to set this to run regularly.
For example, my desktop PC is set to sync with my server every hour. They are both on gigabit so even if I’ve got loads of new data to copy it rarely takes longer than a few minutes.
My server then syncs with an offsite server every night at 3am, when I don’t notice if my broadband is running slowly due to the traffic. (Yes, maybe you consider this to be OTT, but I have lots of irreplacable photos and recordings, and had you considered what might happen to my data if I was burgled and both PC and server were taken, or if a fire destroyed my home and its contents?)
For scheduling regular jobs, cron is your friend. The syntax can be a bit odd but if you open up /etc/crontab in an editor, you can add some comments to the start as a reminder of what each field means. When you’re done, add a new entry to the bottom, like I have here.
# +---------------- minute (0 - 59)
# | +------------- hour (0 - 23)
# | | +---------- day of month (1 - 31)
# | | | +------- month (1 - 12)
# | | | | +---- day of week (0-6) (Sun=0 or 7)
# | | | | |
# * * * * * command to be executed
# run-parts
01 * * * * root run-parts /etc/cron.hourly
02 3 * * * root run-parts /etc/cron.daily
22 4 * * 0 root run-parts /etc/cron.weekly
42 4 1 * * root run-parts /etc/cron.monthly
30 * * * * jonathan /home/jonathan/backup.sh
This command tells my script to run at 30 minutes past the hour, every hour of every day of every month. It is vitally important that you run the script as the same user you configured the key authentication for, otherwise it won’t be able to authenticate. Finally fill in the full path to the backup.sh script we prepared earlier.
If you are running Ubuntu Netbook Remix (UNR), I assume you are also using a netbook. The hourly (or daily, etc) backups described above might not be what you want – you probably don’t have a permanent network. And what if you’re connected via a 3G USB modem, or the slow wireless at friend’s house? Unlikely you’d want to copy several gigabytes of data over such a connection. So the obvious choice here is to put you in charge of when the script runs.
You already know how to run the script manually from the command line, but here we will set up a pretty icon for your desktop. While these instructions are particularly aimed at UNR (because I have it on my EeePC), a similar method will also work in any GNOME environment.
That’s it! Now you can just click the icon to start a backup when you know you’re in a position to make a backup.
This week, the Tuesday Challenge brief is not to take a photograph; but rather to submit the best photograph we’ve ever taken.
Tough one. I’ve managed to whittle it down to two (the first of these Water pictures, and a portrait of my mate Fraser), but I can’t decide between them. So I’ve set up a poll.
On Monday 22nd June 2009 the poll will close, and the winning photograph will be submitted to Stu. Get voting!
Edit: The poll has closed and I’m pleased to announce that Fraser won by a margin of 11 votes to 9.
Today at work I had to install a switch in a rack in a riser. The riser goes from top to bottom of the building in question (5 storeys + basement). Access is through an iron door on each floor.
There is a grille to stand on, but it was slightly wobbly and nowhere near as big as the size of the riser, so I had to be careful where I was putting my feet. The building was constructed in the 1920s and the iron grille and brickwork is original.
It’s a long way to the bottom of the basement. While I was working I dropped a bolt. I heard it hit every grille as it went down, and it took about four seconds to reach the bottom.
This is what I was sent to work on – installing a small new switch in that tiny rack. It’s a Power-over-Ethernet switch to power some new Cisco APs that are going in soon. However, the new switch needed an uplink to the network, provided by…
… the Cisco switch that was bolted flat to the wall above my head, out of reach. You can see the bundle of cables that join the switch to the patch panel.
In order to reach the switch, I needed to stand on a chair. In order to get a chair to not fall through the grille, I had to go and find some pieces of wood. Yikes.
Jonathan Gazeley 