XorgCtrlAltBackspace

Revision 5 as of 2007-06-08 01:58:22

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Please check the status of this specification in Launchpad before editing it. If it is Approved, contact the Assignee or another knowledgeable person before making changes.

Summary

The Ctrl-Alt-Backspace key combination currently "zaps" (hard-restarts) the X server, and thus loses any unsaved data in applications, etc. This key combination is also largely undocumented, so users (probably ex-Windows users) may press this key combination without expecting data loss. This spec covers discussion over either disabling this key combination by default, or documenting it more explicitly.

Release Note

EITHER

The largely unknown key combination of Ctrl-Alt-Backspace, which previously reset the graphics system back to the login screen, has been disabled by default to prevent unexpected data loss and activity interruption for users unaware of its function.

OR

The previously undocumented key combination of Ctrl-Alt-Backspace, which resets the graphics system back to the login screen and potentially loses user's unsaved data as well as interrupting workflow, is now more explicitly detailed to avoid potential accidents for users unaware of its function.

Rationale

The key combination of Ctrl-Alt-Backspace destroys the user's current graphical shell, which by definition can cause data loss. In Microsoft Windows this key combination does not produce any data loss, and can be used to bring up the system monitor ("task manager") or choose between logout/shutdown/task manager/etc. (depending on the system setup). An Ubuntu user who has used Windows (which is an overwhelming majority given the current unbalance) experimenting with known Windows keyboard shortcuts in Ubuntu could lose unsaved data from open applications and interrupt her workflow (logging in again would bring up an empty session if session autosave is not in use) since the effect of this key combination is not made clear to new users. The functionality provided by Ctrl-Alt-Backspace should rarely be needed, and if it is then the same function can be executed from a console.

Use Cases

* Bryce is a relatively new Ubuntu user working on a large image file in the GIMP, but also has Blender open on a different workspace which he used to render the image. Bryce wants to close Blender as he is finished with it and needs to free up some memory for the GIMP. He tries pressing Ctrl-Alt-Backspace, like he used to do in Windows, to bring up a list of open applications so he can close Blender. The key combination does nothing so he decides to open the System Monitor from the System > Administration menu instead. Once Blender is closed he continues to work on his image in the GIMP, saving it when he is finished.

* Katie is writing a guide to help people who are used to Windows to migrate over to Ubuntu. She reads the help manuals for inspiration, then later she is experimenting to find similar functionality between the two systems that she can document. She avoids pressing Ctrl-Alt-Backspace and losing the document, which she has not saved yet, because she read in the help manuals that this would lose her work and send her back to the login screen.

* Joel is accessing the Internet from a friend's computer because the interface on his has frozen due to a graphics driver problem. He still has daemons running which need to remain open, so he cannot reboot. Accessing a chatroom from his friend's computer he is told that pressing Ctrl-Alt-F1, logging in and typing sudo /etc/init.d/gdm restart will restart his graphics system for him, and it will execute in a clean way so his system will not have any unneeded temporary files, etc.

Assumptions

This spec assumes that users do not use the Ctrl-Alt-Backspace functionality regularly and thus would not mind its disabling by default. If this assumption is false then the documentation will be improved instead. The assumption that users who do occasionally use this key combination also know other methods of restarting the X windowing system is made. This spec also assumes that many users will press this key combination without knowing what it does, either out of habit or experimentations, after using a Microsoft Windows system.

Design

Either the "zap" function of the X server will be disabled, or the feature will be documented more explicitly (help pages, etc.).

Implementation

The line option "DontZap" true needs to be added to disable the key combination. The best method for documenting the function of the shortcut should be determined in the discussion of which plan to implement. If disabled this should be made known for a period around its implementation to let users (especially those who would previously have recommended it to new users in forums/IRC/etc.) know of the change.

Test/Demo Plan

To test the implementation the keypress should be used and if nothing happens then it is successful. Disabling the "NoZap" option in xorg.conf should also be tested to assure that those preferring the old system can change back if needed. Help documentation can be opened and checked for accuracy and relevancy.

Outstanding Issues

Either approach can be taken relatively easily. This spec exists to form the discussion over which should be used.

* A GUI option for turning this on or off (perhaps in displayconfig-gtk?)

BoF agenda and discussion

Personally, I use ctrl-alt-bkspace to restart Xorg all the time, but I'm an admittedly unique corner case. As long as there is a documented way to reactivate it (a. comment in xorg.conf, b. on a wiki page, c. maybe in a GUI config tool), this should be fine.

I don't think simply documenting it is an adequate solution. Who reads docs? If it truly is an unexpected data-loss situation for users, then Ubuntu should be changed so that by default it does not happen. -- Bryce

I also use the ctrl-alt-backspace combo quite frequently, as I tend to push my system too hard (running Beryl, 3D apps, etc at the same time). I'm sure that many other people use this combo as well. Maybe it would be good to add an option in the installer, allowing people to choose a set of shortcuts mimicking Windows or keeping GNOME shortcuts. I know that Windows users tend to expect ctrl-alt-del to open the system monitor as well, and there may be others, so this may need looking into. --maccam94


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