PNG Colour mismatch in Internet Explorer

Posted on July 2nd, 2010 in General by Jim Prince

I recently did some web work that involved working with PNG files. I’m not a designer so was using Paint.Net, I haven’t used Adobe Photoshop for years. I came across an odd problem where my saved PNG didn’t match the CSS used on the page even though the hex values for the colours were exactly the same. It was only when I tried opening the webpage in Chrome that I noticed the problem was specific to Internet Explorer.

ie_png

After some Googling I discovered that this is due to Internet Explorer not recognising the gAMA metadata inherent in PNG files. Apparently you can remove the metadata using Adobe Photoshop but Paint.Net has no such option.

I eventually stumbled across a program called TweakPNG which allowed me to open the image and remove the offending gAMA metadata.

Problem solved.

UPDATE: The issue is described far more eloquently then I ever could here.


The most redundant radio button ever

Posted on July 1st, 2010 in General by Jim Prince

Adding SQL Reporting Services to an existing cluster

Posted on June 11th, 2010 in General, Technology, Work by Jim Prince

This morning I had to add SQL Reporting Services to an existing SQL 2008 fail-over cluster. I started the installation selected the existing cluster instance and added the Reporting Services feature. However, when I reached the Installation rules page I got the below failure on the Existing clustered or cluster-prepared instance check. 

"The instance selected for installation is already installed and clustered on computer xxx. To continue, select a different instance to cluster."

SQL Reporting Services


After some investigation I found the following statement buried in the SQL Server 2008 Failover Clustering white-paper

"Note: SQL Server 2008 does not support adding features to an existing failover cluster instance, so Analysis Services cannot be added to an existing instance of SQL Server. To share a resource group with an instance of SQL Server, you must choose to install Analysis Services during the initial installation of SQL Server."

While this is referring to Analysis Services it must also apply to SQL Reporting Services. To get around the issue I carried out a stand alone installation of SQL Reporting Services in "FilesOnlyMode" and used the Reporting Services Configuration tool to create the databases on the fail-over cluster instance. 

I then carried out the same process on the other node in the cluster to create a scale-out deployment as documented here.

All in all quite a frustrating experience, but I got there in the end.

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User renames not being recognised

Posted on June 8th, 2010 in General, Technology, Work by Jim Prince

I recently resolved a problem where one of our applications wouldn't recognise the user type of accounts renamed in Active Directory. The solution was fairly generic so I thought I'd document it here in the hope that it helps someone else.

Basically if you renamed an account in AD and then signed into the application it would still believe you had the old user name. This was proved by navigating to a test aspx page containing the following

< % =System.Web.HttpContext.Current.User.Identity.Name %>

Curiously if you rebooted the server the correct user name was identified so clearly information was being cached somewhere. After some further investigation (by which I mean judicious use of Google) I stumbled across the following Microsoft Knowledgebase Article - http://support.microsoft.com/kb/946358

In a nut shell disabling the local SID cache fixed the problem, renamed users simply needed to re-authenticate to pick up the change to their username.

Note that this does not appear to be an issue under Windows Server 2008.

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Downgrading Windows 7

Posted on March 20th, 2010 in General, Personal, Technology by Jim Prince

Up until recently I’d been using the Windows 7 Enterprise Trial from TechNet on my home PC. Unfortunately it was due to expire, so I purchased a copy of Windows 7 Home Premium as I don’t need Ultimate or Professional at home.

Not wanting to loose my settings I tried to downgrade but was presented with the following error;

Windows 7 Upgrade


After some Googling I stumbled upon a post with a simple registry hack to allow the downgrade.

Once I’d configured the relevant registry keys in HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion (see image below) I was able to perform the downgrade. I am now happily running a licenced and activated Windows 7 without having to install a fresh copy.

Registry Keys

You may argue that a fresh install would be more sensible but frankly its running as well as it did 3 months ago so I really didn’t see the need. Oh and for the record moving to Windows 7 is well worth the effort.


Operating System Analogies

Posted on March 19th, 2010 in General, Technology, Work by Jim Prince

According to Security expert Charlie Miller "Mac OS X is like living in a farmhouse in the country with no locks, and Windows is living in a house with bars on the windows in the bad part of town."

I'd be inclined to agree but it's left me thinking what is Linux or more specifically FreeBSD? The only analogy I can come up with is like living on your own in an underground nuclear bunker with no doors or windows….after Armageddon.

I'm sure you can do better… 

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Links for 19/03/2010

Posted on March 19th, 2010 in General by Jim Prince

GD Library versions and Ubuntu

Posted on January 14th, 2010 in General, Technology, Work by Jim Prince

I'd been having a problem with GD being out of date on a LAMP installation on Ubuntu. This was odd because the installation is the latest (9.10) release. After some digging, it would seem that in Ubuntu PHP5 is not compiled with the version of GD that comes bundled with PHP! 

There's a really helpful article explaining how to recompile PHP5 with support for the latest version of GD here. You'll probably need to update the directories and file names depending on the release you're using but it worked for me.

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Overclocking an Intel E2160

Posted on January 4th, 2010 in General, Personal, Technology by Jim Prince

A while back I overclocked my aging Gigabyte motherboard and Intel Pentium 2160 processor. I overclocked the CPU from 1.8Ghz to 3.0Ghz and the machine has been rock solid with the CPU core temperature around 45° even under load.
 
The motherboard is a Gigabyte ga-p35-s3. Here are the settings I used;
 
CPU Clock Ratio [9x]
CPU Frequency [3.00 Ghz (333x9)]
CPU Host Freqency [333]
System Memory Multiplier [2.40]
System Voltage Control [Manual]
DDR2 Overvoltage Control [+0.1v]
PCI-E Overvoltage Control [+0.1v]
FSB Overvoltage Control [+0.1v]
CPU Voltage Control [1.50000v]
 
I hope this helps someone but of course your mileage may vary. Any changes you make as a result of this post are entirely at your own risk…
 

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Publishing vsftp though ISA – 550 permission denied

Posted on November 24th, 2009 in General, Technology, Work by Jim Prince

A simple one that caught me out recently. I’d setup an FTP site using vsftpd which was published through ISA 2006. By default FTP Filtering on an ISA rule is setup as read only. So if you try to upload a file you’ll get an error 550 permission denied.

Read Only

The fix is simply to right click on the rule in ISA and select Configure FTP. Then un-tick Read Only. Click OK and Apply.