olia lialina: UNDO was a gift from developers to users, a luxury a programmable system can provide. It became an everyday luxury with the first GUI and turned into a standard for desktop OSs to follow. Things changed with the arrival of smart phones: neither Android nor Windows phone nor Blackberry provide a cross application alternative to CTRL+Z (iPhone gave to its users "shake to undo"). What is the logic of these devices' developers? Not enough space on the nice touch surface for undo button; idea that users should follow some exact path (app logic), that would lead somewhere anyway; promise that the "experience" (interface) is so smooth that you won't even need this function.
Should we believe it and give up? NO!
There are at least 3 reasons
1st: UNDO is one of not many generic ("stupid") commands. It follows a convention without sticking its nose into user's business.
2nd: UNDO has a historical importance. It marks the beginning of the period when computers started be used by people who didn't program them, the arrival of the real user, and the naive user.
The function was first mentioned in the 1976 IBM research report "Behavioral Issues in the Use of Interactive Systems" by Lance A. Miller and John C. Thomas. They outlined the necessity to provide future users with UNDO:
"the benefit to the user in having -- even knowing -- of a capability to withdraw a command could be quite important (e.g, easing the acute distress often experienced by new users, who are worried about 'doing something wrong')"
3rd: UNDO is the border line between the Virtual and the Real World everybody is so keen to grasp. You can't undo IRL. If you can't undo it means you are IRL or on Android.
olia lialina: It is great, that finally Tognazinni and Norman noticed that UNDO is gone
"Undo enables a user to recover content. Back is a companion command that enables a user to recover the user’s previous location in a navigational system. The original graphical user interfaces eliminated the user’s need to back up by eliminating navigation. Instead, documents and tools are brought to the user. Browsers and iOS are a throwback to the earlier navigational interfaces, where users wander about a labyrinth of passages leading to modal screens."
olia lialina: While others compete in avoiding and/or ignoring UNDO, Nintendo gave a prominent place to it in the interface of the Super Mario Maker. Undo Dog is back! http://www.mariowiki.com/Undo_Dog