Switched On Tech Design

Tag: troubleshooting

  • Mozilla Firefox: Arrow keys move cursor within the wepage, rather than scrolling. How to fix?

     

    This one seems to be a common issue that people with children and pets encounter; a button-mashing session between said small being and the keyboard can sometimes leave your browser moving a cursor around the webpage when you press the arrow keys, instead of the keys scrolling the webpage up and down. Fortunately it’s an easy fix – it’s a selectable mode called caret browsing mode. Caret is another name for the cursor you see!

     

    To enter or exit caret browsing mode, hit F7. That should resolve this issue straight away.

  • XenServer 6.2: NICs showing as disconnected despite being connected

     

    Sometimes if you connect a network cable to a NIC XenServer doesn’t register it and keeps the status as disconnected; if this happens, try the following via SSH (or from the console, though you will be kicked out of XenCenter once you do it):

     

    xe-toolstack-restart

     

    It may take a little while for the restart to finish but once it does the NIC should be showing the correct status.

  • New CentOS WordPress install: Error 500

     

    Was asked to troubleshoot a client’s installation technique for WordPress on CentOS 6.x yesterday; they were receiving an Error 500 when they tried to access index.php for the first time. Checking the Apache logs showed:

     

    SoftException in Application.cpp:431: Mismatch between target GID (522) and GID (65531) of file “/home/andrea/public_html/index.php”

    Premature end of script headers: index.php

     

    What was happening was that the client was un-tarballing the latest.tar.gz file as root and then changing the ownership of the file with the following:

     

    chown -R [user] *

     

    Changing that command to:

     

    chown -R [user]:[usergroup] *

     

    e.g. here:

     

    chown -R andrea:andrea *

     

    fixed that error. By not specifying the new group there was an ownership mismatch where the system expected one group but got another. There are many  causes for an Error 500 – it’s a good habit to check the Apache logs first for pointers as to where to start troubleshooting.

  • MythTV backend DVB adapter error: ERROR_OPEN

     

    If you see the above error when you’re trying to set up your DVB tuner card one cause is that MythTV can’t get access to the tuner card. This can be because there’s another application installed which has access to it, e.g. something like TVHeadend. On XBMCBuntu you can uninstall TVHeadend by running the following:

     

    apt-get remove tvheadend

    apt-get purge tvheadend

     

    …then retry the setup. If that was the problem it should pick the tuner up now without issue, showing the tuner name in place of ERROR_OPEN.

  • ZFS on Ubuntu error: Failed to load ZFS module stack

     

    If you see the above error in a fresh installation of ZFS on Ubuntu one cause may be that the package build-essentials wasn’t installed prior to installing the ubuntu-zfs package; run:

     

    sudo apt-get purge ubuntu-zfs

     

    then check for the remaining packages with the following:

     

    dpkg –list | grep zfs

     

    …and apt-get purge any remaining relevant ZFS packages.

     

    Then:

     

    sudo apt-get install build-essential

     

    …then install ubuntu-zfs as you did originally:

     

    sudo apt-get install ubuntu-zfs

     

    This time it should take properly. This isn’t the only cause of that error but on a fresh install with a new OS it’s one possibility.

  • Network Troubleshooting: Wireless N connecting at 54Mb/s

     

    This one came up today with a customer who was extending her Wireless N home wifi network with a wireless access point. The access point was reporting a Wireless N connection at a speed of 54Mb/s rather than 150 or 300Mb/s, and transfer speeds for anything connected to the access point were only 2-3MB/s (not unusual for 54Mb/s). The problem in this case ended up being that the access point was set to TKIP encryption rather than AES – using either WEP or WPA-TKIP may drop speeds back to Wireless G speed, which is 54Mb/s max.

     

    Switching the encryption to AES put speeds back to what they should be. This won’t always be the solution but it’s worth checking if you’re seeing that issue.

  • Error Code 60 on an Asus Z9PE-D16

     

    Today a customer’s Asus Z9PE-D16 wouldn’t boot and displayed the debug code 60 – in this case the problem was that the RAM sticks (8 total, 4 for each CPU) were in the black slots rather than the blue slots. Swapping them across resulted in a boot straight away.

     

    Hope that helps someone!

  • Asus P8Z77-V Deluxe not recognising IBM M1015

     

    We had a customer who installed a M1015 into their workstation and it wouldn’t recognise the card at all during the boot process; the board was still on the shipping BIOS 0906, and the issue was resolved by updating to the most current BIOS (1401 at the time of writing). After updating the BIOS the card was recognised during the boot process as normal.