Disable 802.11n on Compaq 6910p with iwl4965 in Ubuntu

I’ve found out that the 802.11n high speed wifi / wlan mode (300 Mbps theoretically) tends to cause more harm than good, i.e. the performance in many, especially crowded, wifi environments will be really poor and it is a better option to turn it off. 

My Compaq 6910p laptop comes with an Intel Wireless WiFi Link 4965AGN chipset. The 802.11n mode can be disabled making it fall back to only use 802.11a/b/g modes casuing the connection to be much more stable and often the overall bandwidth will be better. 

To check if your chipset is running with 802.11n enabled, enter the command:

sudo iwconfig wlan0

The output will look something like this:

wlan0     IEEE 802.11abgn  ESSID:"XXXXXX"  
          Mode:Managed  Frequency:2.462 GHz  Access Point: 00:0C:F6:82:90:28   
          Bit Rate=14.4 Mb/s   Tx-Power=15 dBm   
          Retry  long limit:7   RTS thr:off   Fragment thr:off
          Encryption key:off
          Power Management:off
          Link Quality=51/70  Signal level=-59 dBm  
          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:66  Invalid misc:36   Missed beacon:0

If the first line says 802.11abgn your chipset has 802.11n activated.

To disable 802.11n mode do the following:

sudo modprobe -r iwl4965
sudo modprobe iwl4965 11n_disable=1

This will disable 802.11n until next reboot. Now check again with sudo iwconfig wlan0 and the output should display the first line without the "n" after 802.11, like this:

wlan0     IEEE 802.11abg  ESSID:"XXXXXX"  
          Mode:Managed  Frequency:2.462 GHz  Access Point: 00:0C:F6:82:90:28   
          Bit Rate=54 Mb/s   Tx-Power=15 dBm   
          Retry  long limit:7   RTS thr:off   Fragment thr:off
          Encryption key:off
          Power Management:off
          Link Quality=46/70  Signal level=-64 dBm  
          Rx invalid nwid:0  Rx invalid crypt:0  Rx invalid frag:0
          Tx excessive retries:7  Invalid misc:485   Missed beacon:0

If you want to make this change permanent, i.e. always disable 802.11n, do the following:

sudo echo "options iwl4965 11n_disable=1" >> /etc/modprobe.d/iwl4965.conf

After rebooting, verify using sudo iwconfig wlan0 that 802.11n is not enabled.

 

Share

Posted by on April 24th, 2014 No Comments

Samsung Ultrabook series 5 loses wifi connection intermittently

On a rather new Samsung Ultrabook series 5 we had intermittent / sporadic connection problems on some wifi networks. The status for the network shifts forth and back between ok and "No internet access". This doesn’t happen on all wifi networks. It seems the problem is the 802.11n mode, especially in a crowded wifi environment.

The solution (or workaround) is to disable the 802.11n mode in the wifi driver for the Intel(R) Centrino(R) Advanced-N 6235 chipset. This gives a lower bandwidth connection but on the other hand, a stable connection.

  1. Go to the Control panel
  2. Open Network connections (search for it if you have troble to find it)
  3. Right click on your wifi connection and select Properties
  4. Click Configure in the upper part of the box (my screenshot is danish, so it is the button labeled "Konfigurer…")
    Intel Centrino Advanced N-6235
  5. Click on the Advanced tab
  6. Find the 802.11n mode status configuration parameter and select to set it inactive (off)
  7. Click Save / OK in the bottom 

 

 

Share

Posted by on April 16th, 2014 No Comments

VirtueMart not displaying in Components menu after install [solved]

After installing VirtueMart on a Joomla 2.5 site, it should occur in the Components menu in the Joomla! backend. In my case, it didn’t show up.

The problem can be caused by the Xmap – Virtuemart plugin not being enabled.

Solution: 

Go to the Extensions menu and then select Plug-in Manager.
In the filter box, type "xmap" and press enter.
In the list displaying, check if the Xmap – Virtuemart plugin is disabled (status icon is red).
Then click the status icon for Xmap – Virtuemart so it turns green. Now VirtueMart should be availible in the Components menu.

 

Enabled VirtueMart Xmap plugin
Share

Posted by on April 16th, 2014 No Comments

Fix the Heartbleed Bug on Ubuntu

OpenSSL on Ubuntu can be vulnerable to the Heartbleed Bug. Not all versions of OpenSSL are affected though. 

OpenSSL version 1.0.1 to 1.0.1f are vulnerable.
OpenSSL version 1.0.1g are not vulnerable.
OpenSSL branches 1.0.0 and 0.9.8 are not vulnerable.

To fix this issue on Ubuntu systems: 

Check your OpenSSL version to see if it is vulnerable to the bug:

openssl version

If it says 1.0.1 check the build date:

openssl version -b

If it says anything before Apr 7 2014 you need to update OpenSSL. Proceed as follows:

sudo apt-get update
sudo apt-get install openssl
sudo apt-get install libssl1.0.0

Now verify that you are running the updated OpenSSL libraries:

openssl version
openssl version -b

The build date should now come out Apr 7 2014 or later.

Now you need to regenerate your SSL certificates as they might been compromised. A guide can be found here: https://www.digitalocean.com/community/articles/how-to-create-a-ssl-certificate-on-apache-for-ubuntu-12-04
 

 

Share

Posted by on April 9th, 2014 No Comments

Windows Live Mail (WLM) problem setting IMAP Sent mail folder

When configuring Microsoft Windows Live Mail (WLM) with an IMAP email account, you should set which folders on the IMAP server that should be used for Sent, Drafts, Deleted and Junk email. This is done by going into the setup for your email account in Windows Live Mail, edit properties for the account and select the IMAP tab. Your email server provider should be able to inform you about the correct IMAP folder names. Normally the root prefix folder should be Inbox

However, in some cases (versions) of WLM there seems to be a bug so when setting the root folder to Inbox your Inbox will not be visible in the left pane. A workaround (solution) is to leave the root folder empty and instead prefix your IMAP folder names with "Inbox." like Inbox.Sent for the sent folder. Like this (sorry for the swedish version screenshot, didn’t have an english WLM at hand): 

Windows Live Mail IMAP folders

Windows Live Mail folders for Sent, Drafts, Deleted and Junk mail

Share

Posted by on January 24th, 2014 1 Comment

Joomla multi language problem when trying to change menu item from ‘All’ to a specific language

When setting up a Joomla site for multilanguage you need to set a default menu item for each language. However, sometimes it is not possible to change a default menu item currently set to language "All". The error message displayed is: 

"Warning Save failed with the following error: The Language parameter for this menu item must be set to 'All'. At least one Default menu item must have Language set to All, even if the site is multilingual."

A solution is to do the following:

  1. Select the menu item by checking the checkbox for it to the left in the menu items list.
  2. Then scroll down to the batch change item (found under the list of menu items).  
  3. In the drop down list "Select language" you select the language you wish to set the menu item to.
  4. In the drop down list "Select Menu or parent for Move/Copy", select the menu where item currently is located in.
  5. Select the Move radio button
  6. Click Proceed.

Problem solved!

 

Share

Posted by on November 15th, 2013 No Comments

[Solved] Samsung Galaxy Note II (GT-7105) + Plantronics Voyager Legend bluetooth headset poor audio quality

I recently bought a Plantronics Voyager Legend headset to use with my Samsung Galaxy Note II phone. It worked fine for a day or two, then I started to experience poor sound quality. Especially the person I was talking to had real trouble hearing me. Restarting bluetooth in the Samsung or restarting the Plantronics headset did not help. But restarting the Samsung Galaxy Note II resolved the problem momentarily – after a day or two the problem returned.

Before returning the headset to the dealer I decided to have a look at Plantronics website and found out there are a firmware update procedure availible on their website. To get the update software running on my Windows 8 PC I had to run the installer as administrator. When returning to the update window in the browser (yes, the update procedure is done all in the browser), I found my headset was running firmware version 44 and an update would update it to version 93.

After updating the firmware all quality issues where gone. 

To update the Plantronics headset visit http://www.plantronics.com/us/support/myheadset/updater/

 

Share

Posted by on October 15th, 2013 No Comments

[Solved] Joomla JCE editor displays as plg_editor_jce in global settings

Selection lists in the toolbar might also display things like "advanced.h1" and so on.

The cause of the problem seems to be translation files for the JCE editor of an older version are read only which prevented them from being updated to the newer version. 

Solution: 

  1. Uninstall JCE editor. Go to the menu Extensions -> Extension manager -> Manage. Filter the extensions by entering "JCE" in the filer field. About three lines will be filtered out ("Editor – JCE", "JCE editor" and "Quick Icon – JCE File Browser"). Select all three and click the Uninstall button. 
  2. Using FTP access, go to the language folder and into the folder of each language you have installed in the system, like sv-SE for Swedish for example. Delete the file sv-SE.com_jce.xml in each folder (sv-SE is corresponding to the language folder you are working in so unless you are using Swedish, your filename will not begin with sv-SE but something else).
  3. Now go to the administrator/language folder and into the folder of each language you have installed. Delete all files beginning with sv-SE.com_jce* (and again, unless you are dealing with Swedish, your filename will not begin with sv-SE but something else).
  4. Go to Extensions and reinstall JCE.

In the global settings, you will now find "Editor – JCE" instead of "plg_editor_jce".

 

Share

Posted by on October 1st, 2013 No Comments

PrestaShop categories block empty after migrating from osCommerce

To migrate an osCommerce webshop to PrestaShop 1.5 I used the migration module from Presto Changeo. It worked just as specified, importing categories, products and customers from a running osCommerce webshop. One important thing before you start is that the module will empty all your existing customers, categories and products in your PrestaShop so make shure you are using it on a new shop.

I’ve been working on the PrestaShop installation for a while so it was not a fresh 1.5 install but had been upgraded from 1.3 to 1.4 and then 1.5 (yes it has not been in production before). This is probably the cause of my problems that occured.

The module works fine even if the osCommerce is running on a different servern than the PrestaShop. I small php file must be uploaded on the server running the osCommerce. The import can take several hours especially if there are many products and images. The script can be running in the background emailing you the progress each 5 minutes. If the mail stops coming or you get an error 500 when running in the foreground you simply must go into the module and click resume each time an error 500 occurs until the import is completed.

After the import I could see the categories, products and customers in the back office but the front office blockcategories didn’t show any products. I found that the problem probably was caused by the support for multistore introduced in PrestaShop 1.5.

Solution: 

  1. You need to access the PrestaShop MySQL databas using phpMyAdmin.
  2. Open the table ps_categories. The id_category 1 is the root category. Find which id the home category has (it will have the field is_root_category set to 1). The home category is probably id_category 2.
  3. Open the table ps_configuration and find the key PS_ROOT_CATEGORY and make shure it has value ’1′ (the id_category of the root category).
  4. Find the key PS_HOME_CATEGORY and make shure it has the value of id_category for the home category, probably ’2′.
  5. Go to the back office, in the preferences menu go to the general settings. Activate multi store.
  6. In the advanced parameters menu, go to Multi store. 
  7. Click on the default group and edit your store. Select the Home category as Root category. Save the store.
  8. Go back in the preferences menu general settings and disable the multi store.

Now the categories should display in the blockcategories in the front office. 

Share

Posted by on August 30th, 2013 2 Comments

Vertical and horizontal center img in div

This example shows how an image (img) can be vertically and horizontally centered inside a div. At the same time it illustrates how to resize the image to fit inside the div.

A live view of this code can be seen here. 

<html>
  <head>
    <title>Vertically aligned img in div</title>
    <style type="text/css">
      #container {
        position: absolute;
        width: 600px;
        height: 600px;
        background-color: lightyellow;
        vertical align: middle;
      }  

      #container img {
        max-width: 80%;
        max-height: 80%;
        margin: auto;
        position: absolute;
        top: 0;
        left: 0;
        bottom: 0;
        right: 0;
      }


      p {
        text-align: center;
      }
    </style>
  </head>
  <body>
    <div id="container">
      <img src="sl-buss-6050.jpg" alt="SL-buss 6050" title="SL-buss 6050">
      <p>The yellow box is here to show the div</p>
    </div>
  </body>
</html>

Share

Posted by on June 29th, 2013 No Comments