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A random quotation (don't like it? refresh!)

"Let early education be a sort of amusement, you will then better be able to find out the natural bent of the child"


My latest work:

Holmes NP (unpublished) Multisensory integration: inverse effectiveness and noisy signals. Current Biology, 0:0
  [NBArticle #45652] [Cites 1]

Reader A, Tamè L, Holmes NP (unpublished) Two instances of presyncope during magnetic stimulation of the median nerve, and evaluation of resting motor threshold with transcranial magnetic stimulation (tms). , 0:0
  [NBArticle #45584]

Blanchard CCV, McGlashan HL, French B, Sperring RJ, Petrocochino B, Holmes NP (2017) Online control of prehension predicts performance on a standardised motor assessment test in 8-12 year old children. Frontiers in Psychology, 8:374
    [NBArticle #41777] [Cites 50] [CitedBy 3]

Ubuntu Tips

Worked first-time...

Problems encountered & solved

(A list of the most frustrating problems and their solutions that i've come across since switching wholesale to Ubuntu in December 2008: To remind me, just in case)

  1. Ubuntu 8.10: Limited screen resolution options on Toshiba Tecra M1/XP4m32 graphics
  2. On first installation, my laptop screen resolution was set at 800x600 by default, and in the Screen Resolution program, there were no options to choose a larger resolution. The preferred resolution for my laptop should be 1024x768. Searching the web fora led me to adjust settings in the ~/etc/X11/xorg.conf file. This file is read on start-up, and configures a number of hardware drivers (keyboard, mouse, screen, other devices). It is mostly redundant now, and contains little info by default. For some reason, recent versions of Ubuntu do not work well with Trident graphics drivers (e.g., XP4m32), that were common in old Toshiba laptops. Adding the following code to the xorg.conf file fixed my problem. [xorg.conf]

  3. Ubuntu 8.10: Reinstallation without CD drive
  4. I was stupid enough to mess around with file permissions in my (Toshiba Tecra M1) laptop's file system, causing boot failure and all sorts or carnage. After trying unsuccessfully to reinstate the permissions, I wanted to reinstall Ubuntu, but didn't have a working CD drive or network, so needed to boot from the hard disk. I tried doing a re-install using the ubuntu-alternate-iso, but that didn't work. Here's how to do a full installation using a secondary hard disk partition as a 'live cd'. The most useful web information I found was here.

    You will need: 1) Another working computer (I presume linux, so file permissions can be set, called 'working computer' below), and; 2) A USB caddy or similar way to connect the laptop harddrive to the desktop. Then:

    • Download the latest Ubuntu .iso image onto the working computer
    • Copy the .iso image to a spare (e.g. ext3) partition on the laptop hard drive that you do NOT want to reinstall on, eg: cp /home/nick/Ubuntu_8.10_i386.iso /dev/sdb5
    • Create a mount point for the .iso image on the working computer: sudo mkdir /dev/cdrom0
    • Mount the .iso image on the working computer, with eg: sudo mount -o loop /home/nick/Ubuntu_8.10_i386.iso /dev/cdrom0
    • Extract the vmlinuz and initrd.gz files from the casper directory on the mounted .iso image to the laptop hard drive boot destination: sudo cp /dev/cdrom0/casper/vmlinuz /dev/sdb5 and sudo cp /dev/cdrom0/casper/initrd.gz /dev/sdb5
    • Check/Set the ownership and permissions for each of the three files on the laptop hard drive to root, eg: sudo chown root /dev/sbd5/vmlinuz and sudo chgrp root /dev/sdb5/vmlinuz (and for the initrd.gz and .iso files)
    • Change the /boot/grub/menu.lst on the currently-booting laptop drive (the one that will be overwritten in the re-installation), to include the following as the first option in the list of different boots (change path-to-file as appropriate):

      title Install Ubuntu
      root (hd0,4)
      (i.e., the 5th partition of hard disk #1, sdb5 when mounted in the working computer)
      kernel /vmlinuz boot=casper iso-scan/filename=/Ubuntu_8.10_i386.iso
      initrd /initrd.gz

    • Stick the laptop hard drive back in the laptop, turn it on
    • If all the above was correct, then you'll get a verbose output of installation and configuration information, and hopefully it will boot up into the 'live cd' where you can continue the installation.
    • If not, you'll get 'File not found', or 'this partition can't be booted', or the same problems as you were having before. If the grub menu is on screen, then you can edit it manually to get the right location for the boot .iso image. On my laptop, the partition numbers assigned to the disk were not the same as on the desktop, for example, so required manual editing of the grub boot list during installation
    • Assuming the 'live disk' boots, there's one final thing to do before continuing the installation as normal: to remove the loop mount of the .iso image from the now-booted hard disk, by: sudo umount -l /dev/sda5
    • Double-click the install disk icon on the desktop and proceed as usual

  5. MySQL server deactivated / doesn't start after installing XAMPP
  6. Re-installing XAMPP after the carnage described above, and the MySQL server would not start properly. There are probably thousands of similar error-message reports on the web, with many many different solutions - sometimes just re-installing, sometimes turning off or re-configuring other programs, sometimes just giving up. My solution was relatively quick:

    1. Repeat the sequence I used the first time I successfully installed it: Install several available Ubuntu-ready MySQL and Apache/php packages from the synaptic package manager, then when they seemed to be working, uninstall them, and turn off the Apache/php and MySQL server services that start at boot. Then, install XAMPP with the superstition that all the previous work did some good mojo
    2. Somewhile during 1, I realised that the md5sum of the XAMPP package I downloaded was wrong. So, after 5 more download attempts, I got an uncorrupted one, installed it, and all was fine - MySQL worked first time
    3. After moving /opt/lampp to a new partition, MySQL stopped workng again. Simply extracting the good version of XAMPP in the new directory, and setting the relevant file permissions fixed all problems

    Who knows whether it was 1) or 2) which fixed it. 2) seems most likely...