Printer driver for Canon MG-7100 on Ubuntu

Once again I was solving a computer problem for my parents-in-law ;-). This time, it was yet another new printer they had bought – a Canon MG7100. Usually, I have had a really good experience with modern Ubuntu and popular printers. They Just Work. And this time it seemed things had gone well again. And they almost had. Except the colours were a bit off. On the Ubuntu printer test page Magenta was brown, bright green was instead a darker green, and yellow was very muddy – more like taupe. I wasted a lot of time cleaning ink nozzles etc etc but the actual solution was to choose a slightly different driver manually from the Canon list. There were two v4.0 options and it was the second that worked.

Category Good setting Bad setting
Job ID Canon-MG7100-2-671 Canon-MG7100-665
Driver CNMG7100.PPD STP00541.PPD
Driver Version 1.0 5.2.10-pre2
Description Canon MG7100 Canon MG7100
Driver Version Canon MG7100 Canon MG7100
Make and Model Canon MG7100 series Ver.4.00 Canon MG7100 series – CUPS+Gutenprint v5.2.10
Printer Canon-MG7100-2 Canon-MG7100

Hope this helps someone else.

Eclipse and PyDev on Utopic

I upgraded to Utopic (Utopic Unicorn a.k.a 14.10) and eclipse wouldn’t complete loading anymore. Solution:

Download latest plain vanilla Eclipse from the standard downloads page. And feel free to donate something too.

sudo su

chown -R root:root /home/username/eclipse && mv /home/username/Downloads/eclipse /opt

ln -s /opt/eclipse/eclipse /usr/local/bin/eclipse && exit

Start by running:

eclipse

It didn’t even break PyDev so my luck’s finally turning ;-).

https://www.tumblr.com/search/install+eclipse+ubuntu

Testing new Ubuntu versions

Newer Ubuntu versions are less dramatically new these days, which is probably a good thing, but I like to take them for a spin anyway – old habits and all that. One nice change since the days of Dapper Drake is the ability to boot off a usb stick – much easier than having to burn CDs. On my laptop, I get to the boot menu by pressing the Esc key soon after booting and then selecting the USB stick to boot off. But there can still be problems. In particular, I was receiving the error message:

gfxboot.c32: not a COM32R image

Turns out you need to press the tab key and then type in “live”. Obvious really (not) Ubuntu 14.04 LTS live USB boot error (gfxboot.c32:not a valid COM32R imag).

Another good thing about modern Ubuntus is that they generally work out of the box just how I like them. I remove items from the launcher, shrink the icon size and add the Show Desktop icon to the launcher (under System Settings > Appearance), and I’m almost good to go. There is still one thing that takes a bit of fiddling – adding the ability to minimise on click (Ubuntu 14.04 Adds ‘Click to Minimize App’ Option to Unity Launcher).

Step 1: Open Ubuntu Software Centre
Step 2: Install CompizConfig Settings Manager
Step 3: Open Ubuntu Unity plugin
Step 4: Launcher > Minimize Single Window Applications (Unsupported)

On the one hand the version changes aren’t as exciting as they used to be, but on the other, it’s never been easier to check them out.

IDLE3 as default for py files on Ubuntu

Yes – I know, there are better alternatives to IDLE out there, but I am used to it for quick and dirty changes to python files (I use eclipse + pydev for more serious work). And I am increasingly making the switch to Python 3. So when I double click on a py file, odds are I want to open it with IDLE for Python 3 not Python 2.

Start by making sure you have a desktop file like the following:

gksudo gedit /usr/share/applications/idle-python3.4.desktop

[Desktop Entry]
Name=IDLE (using Python-3.4)
Comment=Integrated Development Environment for Python (using Python-3.4)
Exec=/usr/bin/idle-python3.4
Icon=/usr/share/pixmaps/python3.4.xpm
Terminal=false
Type=Application
Categories=Application;Development;
StartupNotify=true

Then make the desktop entry the default for python files:

gedit ~/.local/share/application/mimeapps.list

[Default Applications]
text/w-python=idle-python3.4.desktop

Note – no trailing semi-colon.

And in Linux Mint:

Linux Mint:

ls /usr/share/applications/

identify appropriate .desktop file

gedit /usr/share/applications/defaults.list

add the appropriate .desktop file reference at the front of the python line as appropriate.

Installing iNZight on Ubuntu (13.10)

Existing documentation for installing iNZight on Ubuntu covers a wide range of possible scenarios in Step 1. For my own specific case, however, I needed to translate it into a series of precise step-by-step instructions.

So here are the instructions that worked for me for Step 1. Once that is done, just follow steps 2 onwards in the official docs.

STEP 1 STEP-BY-STEP

It is probably best you don’t already have R already installed. And if you’re using iNZight, you probably won’t. But if you do, purge it! Installation may or may not work depending on the version of R you install so remove one source of difference from what the support people will have tested.

  1. ctrl-alt-t to open terminal window
  2. sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys E084DAB9
  3. sudo gedit /etc/apt/sources.list

    and then append
    deb-src http://cran.stat.auckland.ac.nz/bin/linux/ubuntu saucy/
    Note: must have trailing slash (/) at end
  4. Click on “Save” button on toolbar or enter ctrl s on keyboard to save
  5. sudo apt-get update
  6. sudo apt-get install r-base
  7. Open R by typing R into terminal
  8. From R prompt:
    update.packages(ask = FALSE)

    y to everything

  9. q("no")

    to quit the R prompt.

  10. Then follow steps 2 onwards in the official instructions …

Dual boot Samsung 700 Ubuntu / Win8

My Mother found Windows 8 very bewildering (actually, so did I) and asked me to install Ubuntu (13.10) instead on her Samsung 700 tablet/notebook. I thought I’d set it up dual boot so I could occasionally use Windows 8 for testing purposes and in case there was any sofware that we needed in the future that was Windows only.

  1. Power off
  2. Put bootable Ubuntu USB in
  3. Boot but hold down F2
  4. In the BIOS config (it was touchscreen which was quite nice):
    • Advanced:
      • Fast BIOS Mode: Off
    • Boot:
      • Secure Boot: Off
      • OS Mode Selection: CSM and UEFI OS
      • PXE boot: On
  5. Save>Yes
  6. Reboot but hold down F2
  7. Boot to Device now showed: UEFI: DSE MicroDrive 2GB 1.00 (or however your USB identifies itself)
  8. Boot into Ubuntu installer
  9. Shrink Windows partition (the NTFS one)
  10. Add a large Ext4 partition for Ubuntu and a smaller swap partition
  11. Install Ubuntu onto the new Ext4 partition with / as mount point
  12. Reboot and set everything up. Success :-).

Canonical – ignore the hate and make your bet

Does Canonical deserve the hate that is being directed at it by some people? I doubt it – who could? Canonical deserves criticism for some things, of course, but not the ongoing and disproportionate spite some technical people direct at it. The only explanation I can come up with is that when some people love or believe in something strongly, and then are disappointed in that love, they can feel very, very angry. And as with romantic love, nothing will make them feel better till they have a new love to take the place of the old one. So I’m not sure there is much Canonical can do to appease them. Instead, the focus should be on the big bets it has to make to secure a future. The following comment (on Slashdot) captured the issue especially well so I quote it in full:

It’s not rocket science. Rightly or wrongly Canonical has decided that the future of general computing is in the mobile space and they are working on getting Ubuntu there and bridging the gap between the mobile computing experience and the desktop computing experience.

In simplest of terms, they’re trying to make a distro that can be both a phone and a desktop all in the same device. Again — rightly or wrongly — they have decided that they needed to move certain things in house to best accomplish that goal (Mir) and needed a specific interface they were in control of to scale between display form factors (Unity).

If you are a person that thinks this direction is wrong and will hurt Linux in the long run, then you belong in the “bad for Linux” category. I’m a person that thinks this is absolutely the best way for Linux to finally have its “year of the desktop” similar to how Apple made their comeback but with a twist — by providing a compelling mobile experience with a device that just so happens to be able to double as someone’s desktop when they want a bigger screen.

Pay attention to plunging desktop sales numbers. As people find ways to make mobile devices and tablets their only computing devices, this strategy will start to look smarter and smarter. Whatever else you think of Canonical (and by extension Ubuntu), this will either make them or break them.

Ubuntu good for linux?

As with most big bets, there are no guarantees of success. And Canonical will make mistakes. But I fully support their attempt and wish them well.

Kernel panic fixed on mother’s laptop (Ubuntu 13.10)

My mother’s laptop started displaying an alarming message:

(3.347276) Kernel panic - not syncing: VFS: Unable to mount root fs on unknown block (0, 0)

The good news is that this seemingly terminal problem has proved easy to fix (so far anyway 😉 ).

  1. Hold Down the Shift key when booting to see the GRUB menu displayed
  2. Press the Escape key to get to the menu
  3. Select a different kernel to boot into instead of the one that has been panicking
  4. Do whatever needs to be done as per [SOLVED} kernel panic-not syncing: VFS: unable to mount root fs on unknown block(0,0)

In my case, I removed numerous kernels (Note – leave a couple behind including the two most recent)
sudo apt-get remove linux-image ...
sudo apt-get autoremove

and was advised by the terminal to run
sudo dpkg --configure -a

Picasa 3.9 + F-spot together on Ubuntu

Some people want to use F-Spot and Picasa together – F-spot to import and tag photos; and Picasa to do minor editing ready for printing. Here’s their desired workflow:

  1. attach camera
  2. import into F-Spot
  3. do editing in Picasa
  4. want any changes to also be the same in F-spot.

This should be manageable given that Picasa can work on existing files, without having to separately import them to a different place on the file system. So the photo files are where F-Spot put them, and, irrespective of how Picasa organises them in its own “virtual” folders, changes made to the photo in Picasa alter the original photo in its F-spot location. So far, so good.

But there is one issue. If you install the last version of Picasa made for Linux, it is significantly out-of-date. It works as described with Picasa, but it is old. And if you install the latest version of Picasa (3.9) under WINE (instructions), a problem occurs when bringing all the photos into Picasa. Instead of merely pointing to the file locations for the photos, Picasa actually separately makes copies of them. Which means that when you edit them, the original in F-spot is unaltered.

Fortunately, there is a workaround and it involves changing the way Picasa watches folders. It requires some simple edits to the watchedfolders.txt file in: /home/username/.wine/dosdevices/c:/users/username/Local Settings/Application Data/Google/Picasa2Albums

Note: even though you might be using Picasa 3.9, the path is Picasa2Albums.

Make the following alterations as appropriate, depending on which folders you have photos in:

C:\users\username\My Pictures\ –>

/home/username/Pictures

/home/username/Pictures\

C:\users\username\My Documents\ –>

/home/username/Documents

/home/username/Documents\

C:\users\username\Desktop –>

/home/username/Desktop

/home/username/Desktop\

Note that both versions seem to be needed (see also How can I get Picasa to view my second HDD?).

[UPDATE]

Here are some extra issues I encountered:

  • One huge gotcha – Picasa cropping must be Saved to change the file on disk. Clicking on “Apply Change” is not enough to change the file on disk even though the change persists within Picasa. If it isn’t saved, the change is only visible when looking at the image in Picasa – it won’t show up when looking at the file otherwise (e.g. using ImageViewer) and that includes F-Spot. Can’t really blame F-spot for that.
  • F-Spot doesn’t automatically know about files put into its folder structure e.g. if you manually insert an image into /home/username/Photos/2014/03/03 f-spot won’t display it.
  • Picasa only grabs images from the watched folders if they have an image extension e.g. .jpg. Otherwise it ignores them.

The net result is that if you want a simple workflow where you view and tag photos in F-Spot and modify images using Picasa you should follow these instructions:

WORKFLOW INSTRUCTIONS

  • Only put images into F-Spot using import. Don’t manually put images into the standard folders F-Spot uses e.g. “Photos/2014/03/03/”.

    A simple workflow is to have a standard folder under Photos e.g. “Photos/0 Upload These” where you put copies of photos whether you get them from a camera or from another source e.g. as email attachments. You can give these human-readable names such as me_at_beach.jpg rather than IMG9805.JPG etc before importing them. Once imported into F-Spot (and thus copies put into the date-driven folder locations), empty the “Photos/0 Upload These” folder.

  • Save changes in Picasa – don’t just Apply Changes.
  • If you want multiple versions of an image, make them in F-Spot so F-Spot knows about them, then edit the extra versions in Picasa.

    To create new versions in F-Spot File, select a photo, then Photo>Create New Version in the menu.