Google App Engine has just added some more invitations for developers who missed out on the first round.

http://appengine.google.com

With only 1 more day left to the official release of Ubuntu 8.04. Check back here were we will give any guides and tips needed to get this release installed under Parallels on the MAC and also VMware fusion offering. I will also go true the details for anyone who has already 7.10 installed and wants to preform an upgrade.

This week I was working on a new project and for the project I needed to keep an eye on the lenght of a queue which was stored in a MySQL table. I already have the very useful MRTG tool installed on the server so I decided to make use of it to create a simple a quick graphs.

For anyone who doesn’t already know what MRTG is its a very handy tool for graphing data. It is normally used to graph things such are network interface traffic stats and works with an RRD data store in the background storing 5 minute averages. MRTG makes it very easy for users to monitor custom data aswell and has a simple input format. All that is required is to write a script which will output 4 lines of data.

Line 1 -current state of the first variable, normally ‘incoming bytes count’
Line 2 -current state of the second variable, normally ‘outgoing bytes count’
Line 3 -string (in any human readable format), telling the uptime of the target.
Line 4 -string, telling the name of the target.

In order to get started graphing that data that I wanted I created this small script below

#!/bin/sh
echo 0
mysql -h localhost -u USER –password=PASSWORD -e “$1″ DATABASE | tail -1
echo 0
echo “Queued Items”

When this script is called it takes 1 argument which is in the form of the count query you want to preform. eg “Select count(*) from table_X”

Then in our MRTG cfg file we need to add an entry to call and display this data.

Target[Blackarrow_queue]: `/graphs/collector_links “Select count(*) from table_X”`
MaxBytes[Blackarrow_queue]: 10000
Options[Blackarrow_queue]: nopercent,growright,nobanner,nolegend,noinfo,gauge,integer,transparent,noi
Title[Blackarrow_queue]: Queue Lenght
PageTop[Blackarrow_queue]:<h3>Queue</h3>
YLegend[Blackarrow_queue]: records
ShortLegend[Blackarrow_queue]:
LegendI[Blackarrow_queue]:
LegendO[Blackarrow_queue]:records

For a graph like this you’ll want to use similar options to the ones I used above. nopercent disables percentage display, growright tells the graph to read from left to right instead of the default right to left, gauge tell MRTG that the data points are “current status” measurements rather than ever-increasing counters, noi tells MRTG there is no “input” data to compare against “output” data and a few cosmetic display options. The resulting graph looks something like this:

Im working on a project now and using subversion a lot for the project. One of the things that has been annoying me in the last while is sometimes I want to move code into another svn repository while working on it, and really the only way to do it is to remove all the .svn directories check out the top level empty directory of the repository I want to place the code into and then do svn add *

The only problem been that removing all the .svn files can be a real pain on large projects.

find . -type d -name ‘.svn’ -print0 | xargs -0 rm -rdf

Is a very handy command that I now use all the time. What this does is find all the .svn directories and removes everything below them, leaving me free to add the code back into another subversion repository.

Update: This is also very handy way of reducing the transfer size if using SCP to move your code between servers. As when working on SVN subversions files the .SVN directories can double the size of your code on disk as they store copies of the files in the .svn folders for later comparison

So this morning I was doing some work with one of my webservers and adding new sub hosts to some of the domains and to see the changes on my MacBook pro laptop I knew I would need to flush the DNS cache so I wouldnt have to wait for the cache to expire.

So for anyone else who needs to know the commands here they are:

OS X <= 10.5.1

lookupd -flushcache

OS X >= 10.5.2

dscacheutil -flushcache

Hope that will help anyone out there who needs to flush their dns cache and has just upgraded to 10.5.2

The majority of us don’t backup on a regular basis. It usually isn’t until we lose a bunch of critical data that the light bulb turns on and we start backing up for maybe a week or two and then we stop. Apple’s new Leopard operating system contains Time Machine to fix that problem. Time Machine runs in the background, backing up your entire hard drive without you having to remember to manually run a backup.

This was one of the niceties which excited me about upgrading to Leopard; however I was somewhat disappointed to learn after upgrading, that Time Machine would only backup to another physically attached hard drive. In my situation I primarily like to place my backups in a remote location such as a networked server. I work of a laptop, so my physical working location is always changing and I’m not going to carry an external drive with me all the time. Luckily, after a few hours of research I found a nice tweak to let me use our office network servers as my backup location.

Here is how you do it:

REQUIREMENTS
Obviously you need to be running Leopard and you’ll need a network share which is larger or equal to your hard drive in your Mac. In my case these shares are in SMB and AFP.

1. Go into Applications / Utilities and open up terminal
2. Copy and paste this command into terminal (all on one line)

defaults write com.apple.systempreferences TMShowUnsupportedNetworkVolumes 1

3. Hit enter / return
4. Mount your network share, in my case my share is off our server called INAS1 and my share is called User-Backups
5. Go to System Preferences and open Time Machine
6. Click on Change Disk
7. Select the share you wish to backup to, I’ve selected User-Backups
6. That’s it, you’re done

Wait up to 15 minutes and you should be set. To verify it is working open up your network share in Finder and you should see a file which is named [your computer name] [your MAC address].sparsebundle

Be sure you post any comments or questions about this method.

Cool little project I found. Check out WinFUSE. Its a fully functional file system running in .NET. And you can write your own with the IFileSystem interface. This could be very cool! Write your own file system with SQL server, Amazon S3 or anything in the back.

With over 300 new features:

They ones that appeal to me there most are

Quicklook: Using Quick Look in Leopard, you can view the contents of a file without even opening it. Flip through multipage documents. Watch full-screen video. See entire Keynote presentations. With a single click.

Quick Look works with nearly every file on your system, including images, text files, PDF documents, movies, Keynote presentations, Mail attachments, and Microsoft Word and Excel files. Just tap the Space bar to see a file in Quick Look, or click the Quick Look icon in the Finder window (if it’s not there already, add it by selecting Customize Toolbar from the View menu in the Finder). Then click the arrow icon to see the same file full screen — even video as it plays.

Spaces: You do a lot on your Mac. So how do you keep order when projects pile up? Easy. Use Spaces to group your application windows and banish clutter completely. Leopard gives you a space for everything and makes it easy to switch between your spaces.

Boot camp: Leopard is the world’s most advanced operating system. So advanced, it even lets you run Windows if there’s a PC application you need to use. Just get a copy of Windows and start up Boot Camp, now included with Leopard. Setup is simple and straightforward — just as you’d expect with a Mac.

Dashboard Webclip: Clip out any portion of a web page and turn it into a Dashboard widget. Just click the new Web Clip icon in Safari and select the portion of the page you want, then click Add to see your Dashboard spring to life with a brand-new widget. The widget is “live” and will update as its page of origin does. You can even customize your widget’s frame.

Instant Screen Sharing from the Finder: Start an interactive screen sharing session with other Macs on your network. Just select the Mac from your sidebar and (if authorized) you can see and control the Mac as if you were right in front of it. Change a system preference, publish an iPhoto library, or add a new playlist to iTunes.

Smooth Zoom and Scroll: Smoothly zoom and scroll through even the largest image files. Preview uses the power of Core Animation.

Enhanced VPN Client Compatibility: Connect to a broader range of VPN clients. Leopard supports Cisco Group Filtering as well as DHCP over PPP, which allows you to dynamically acquire additional configuration options such as static routes and search domains.

Merge All Windows: Combine all your open Terminal windows into a single window with multiple tabs.

There the features I will be using the most. As soon as I get my copy of Leopard I will write a review of the install process for you.

Here is how I got Ubuntu 7.10 installed and working on my parallels virtual machine, also you might find Ubuntu 7.10 Linux Unleashed a very useful book to read.

VM Memory: 512 HD size 6-10GB

1. Boot the install CD. When the menu screen comes up press F6 for boot options before it starts the install

2. Delete the ’splash’ option and press the Return key to start up the installation. This will prevent the terminal window from being hidden by a splash screen so you can do the next steps.

3. The install system will begin to boot and the display server will die as before. However now it will go back and forth between the graphic display window and the terminal window. During the moments that it is in the terminal window you can type to the command shell. If it comes up with the window that says ‘The display server has been shut down about 6 times in the last 90 seconds’ go ahead and type Return to select the OK and you will again get the terminal window and in a few minutes get the dying display server again. Persevere and you can keep typing thing in the terminal window.

4. First type ctrl-c to kill the script and get you a shell prompt. Then using vi or pico as you prefer, edit xorg.conf as root:

sudo pico /etc/X11/xorg.conf

5. Scroll down to the Device section (not Input Device), and insert inside it the line

Option “LVDSBiosNativeMode” “false”
then save the file and exit the editor.

6. Start up the display server again by typing the command

startx

This will bring up a window filled with a grey pattern. Have patience and wait, and in a minute or two you will get a real Ubuntu desktop with an Install icon on it. Double-click the Install icon to start up the install process.

7. The display server error will keep happening, but the install continues anyway. Whenever you get the ‘The display server has been shut down about 6 times in the last 90 seconds’ window you have to type Return again to get back to the install window. It is really annoying having to do that every few minutes, but eventually the install is completed.

8. However you are not yet done. If you reboot after the installation (remember to disconnect the install CD) you will still get that display server death problem. The next steps are to get rid of that:

9. Reboot the virtual machine and when it says to press ESC to get the boot menu, quickly press ESC to get the boot menu, scroll down, and boot in recovery mode. That gives you a root shell prompt in a terminal window.

10. Type the appropriate keys to get your mouse back and in Parallels’ Actions menu select Install Parallels Tools. That will show you instructions on how to install the tools, and will connect the tools CDROM image.

11. At the root shell prompt, type the commands that you were shown to install the tools

mount /media/cdrom
cd /media/cdrom
sh parallels-tools.run
shutdown -r now

12. That last command reboots the virtual machine. When it comes back you should have a working Ubuntu 7.10

I would also recommend Ubuntu 7.10 Linux Unleashed, 3rd Edition

So earlier today I was trying to install the latest version of Ubuntu 7.10 on my Macbook pro with out any success.

Turns out there are some issues with the VM machine and memory, by setting the VM to use only 512MB instead of the 1024MB I had alloted first time round the installer process now runs without crashing.

Updated: See Ubuntu 7.10 install guide parallels

Ubuntu 7.10 Linux Unleashed, 3rd Edition