Monthly Archives: March 2011

Hyper-V Centos VM date time clock gains hours even with ntp

I have a system at home that is used for test and dev work. It’s a windows 2008 server with Hyper-V with various VM’s running including SME Server which is based on CentOS.

The clock has been playing up with time gains in hours and this messes me up when looking at logs etc.

I think it may be resolved thanks to Michaels blog post.

For future ref the change is in the /boot/grub/grub.conf file and we need to add

divider=10 clocksource=acpi_pm

to the kernel line, i.e. on the line that starts with ‘kernel’ as part of the command.
 

DVD Ripping software

I had a task set for me to rip some DVD’s so that they could be watched on our TV, iPhones, iPads, PC’s and on a Mac and preferably via a an x-box.

So I set out to try for the very first time some DVD ripping software. (So I was late to this party!)

Now I have to say that after two days I think it is a minefield of marketing rip-offs. To save you reading further Magic DVD Ripper is my winner. But if you want to know what else I looked at have a quick read. It might save you some wasted downloads.

AVS software. Buy “Unlimited LifeTime licence” that is limited to only one computer for the life of that computer.  Get a new PC and it expires just like Microsoft Windows licences. What crap.The software to convert files is as slow as a wet week in any case. Don’t waste your time. And watch out for the ‘independent reviews’ that provide links to buying this as they are all on a commission basis.

Wondershare software DVD Platinum product looks ok but alongside Aimersoft DVD Ripper you can see that they are exactly the same software with a different skin. This raises the questions of why and which is the original? My watermarked file (note that you dont find out about the watermarks in the trial until you go to save the ripped file.) did not render correctly in any case. Note that I am new to this and the fact that the frames seemed to hesitate and jump with ghosting struck me as being a poor quality rip. Tried Aimersoft but it is ripping at a rate that would make snails look quick.

AnyDVD, espoused as really good, nagged the heck out of me with constant reminders that I only had 21 days left of a 21 day trial within 5 seconds of the install completing. Every time the screen changed it nagged. For crying out loud, let me use the software and not undertake a olympic practice session in clicking OK buttons on annoying prompt boxes.  In the end it ripped the TV series DVD into a mountain of small files that split the episodes up into fragments. Quality output but and annoying process and I am not sure how to join the files back together and slow as well.

Next I tried the appropriately named, ‘Next DVD Ripper’ which seemed to run really well but the output was crap. Tried on a cartoon/animation DVD and got gross pixelation as if the digital broadcast was failing on the cable TV. Could not playback properly on anything. Tried again with TV series episode and got average picture and lipsync issues that were so bad I could not tell who was speaking.

WinX DVD Ripper Platinum. Given the similarity of the name with the Wondershare/Aimersoft clones I wonder if the back-end is similar. It will, once you work out how to modify the settings, rip a decent copy although I am sure that I am hearing a bit of wow/flutter as if it is an old audio cassette tape on a worn deck in the sound quality. Probably ok but it still did not shake me from Magid DVD Ripper. But I will at least provide a link to this as a worthy runner up.

HandBrake is an opensource ripper, but it is not quick and does not do some of the things I would like. I think I needed to tweak settings more but gave up.

Magic DVD Ripper.  Ripped the TV episodes to mpeg-2 format in rapid time and they work perfectly on the TV. Next tried ripping to an iPad format and tested.  It does not convert existing files. It only rips from DVD, so converting a file requires another product, but it is quick with ripping and gives great audio and video quality without messing with settings.

So the next task is a video file format converting application to take the TV/DVD quality mpg’s from Magic and convert them quickly and easily to iPad and other formats for viewing on the move.

In case you wondered, our TV is the Panasonic Viera 3D with the Synology Media Station linked over our ethernet 1G LAN. We also have an Xbox 360 on an older TV in another room that I’ve managed to hook to the Synology as well for music. I’ll be trying video’s next weekend.

Moodle upgrade from 1.9 to 2.0

The actual versions of the upgrade are v1.9.5 (live) and moving to 2.0.1+ (daily download from Jan 2011).

The server had been setup with a working copy of the live system from January and tested through an upgrade to 2.0.1+ so we were happy that all would work well. This upgrade was also a server migration from an older RedHat box to a Debian vm, but the principles are the same for any upgrade. The Moodle version to be used was already installed as a staging platform.

The following notes relate to the process that I used for the live cut-over.

Backup of live 1.9.5 database via phpmyadmin

Copy the moodledata directory (the one with the files) from live to new
(must change owner and ensure write permissions after copy or you will get an odd blank page in the middle of the upgrade)
I used rsync to transfer between the servers here.

database created live_2 : (note to self:ensure utf8 collation setting for the db in future)
import old 195 data to new db
config.php modified to use the new db
run moodle2 as admin
auto upgrade : error check references installing UTF8. This is because I forgot to set collation = utf8 corrected* and reran upgrade

Update DNS settings (transferring from one server to another)

Changed apache config on new server to accept the new virtual host.

*Correcting the collation is as simple as using your mysql admin tool and issung ‘ALTER DATABASE db_name COLLATION ‘new collation name’;
with the new collation name inside single quotes.

WordPress gives 404 error with password protect on wp-admin directory

Damn, but that was a long-winded process. I’ve just spent the better part of 4 hours reading and researching why I get (got, its fixed now)  404 errors from wp-admin when I enabled .htaccess Authentication (htpasswd) for the wp-admin directory. It only happened with WordPress MU / Network config.

googling for this error ends up with a mountain of irrelevant threads, inconclusive discussion, and unanswered questions.

WordPress single user 3.1 is not affected by this as there are no ReWrite rules required for the wp-admin. The issue only occurs with MU or Network as it is now called in WP 3.0+ as there is a set of ReWrite rules in the .htaccess file that look like this:

RewriteCond %{REQUEST_FILENAME} -f [OR]
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule ^ – [L]
RewriteRule ^[_0-9a-zA-Z-]+/(wp-(content|admin|includes).*) $1 [L]
RewriteRule ^[_0-9a-zA-Z-]+/(.*.php)$ $1 [L]
RewriteRule . index.php [L]

The issue is that the prompt for the username and password that should happen automagically cannot occur due to the rewrite rules.

The rewrite rules are to look for a valid directory or file and if it is not a valid directory or file then redirect to the index.php which is what happens as the htpasswd AuthConfig process is not a valid file or directory (apparently – umm, so what is it? like is there another rewrite rule that would avoid this? obscure Apache voodoo)

The fix is to create a valid file as an ErrorDocument directive for a 401 or 403 error (Authorisation errors) and have this at the top of the .htaccess file so that Apache will return a valid file flag and therefore allow the AuthConfig prompt to occur.

Edit your top level .htaccess above the section for #Rewrite for WordPress

ErrorDocument 401 /myerror.html
ErrorDocument 403 /myerror.html

if you dont want to put this dummy file in your site root then add the path to the filename

ErrorDocument 401 /[path_to_file]/myerror.html
ErrorDocument 403 /[path_to_file]/myerror.html

Then just create an empty file with that name in the appropriate path.

The references that I used were:
http://www.scratch99.com/2008/10/password-protecting-the-wp-admin-folder/
Which is where I finally found a decent reference that was related to the issue and that blog referenced this one,

http://developedtraffic.com/2007/05/27/wordpress-admin-password-protection-404/
Which pointed me at TextPattern http://textpattern.com/faq/173/password-protected-directories-with-htaccess

and for good measure, this site helped to complete my understanding of why this process works.
http://www.ju-ju.com/2006/03/17/wordpress-404-error

Thanks to the authors of each of those sites.