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The History of the "Undo" Function?
TheLocustNMI asks: "So, earlier today as I was typing out some magnum opus of a stored procedure, I highlighted to copy it, and hit SPACE instead of Ctrl-C. Without thinking, I hit Ctrl-Z to 'undo' my folly. Pausing a moment to reflect, I realized that I own countless hours of thanks to whomever came up with the "undo" button. In short -- my question is this -- where did it come from? What are the earliest implementations of the 'undo'? (a quick googling returns this page, a cornucopia of undo and history related treatises)"
The "undo" button before computers was white-out. You could never have enough of that stuff around. Especially if you were from a family like mine with several kids doing term papers.
A better place to ask this question would be alt.folklore.computers on usenet.
Seeing how things have been lately, it's worth finding an answer for this question before someone attempts to patent the idea.
IIRC, there was an example in the Arabian Nights. Of course, this was long before computers but it still worked like magic.
-- MarkusQ
P.S. On a more serious note, I wouldn't be all that shocked to learn that 'undo' wasn't implemented on a computer before the 1970s. My main reason for thinking that is that it is relatively expensive, and really only useful in interactive environments. When you're editing your program by manually shuffling h-cards, there isn't much sense in having "undo".
.. or do you find yourself saying "Control-Z" in your mind whenever you find yourself making mistakes while not sitting in front of a computer..spilling a glass of milk...etc
That's right people ... Apple did it first (at least in a consumer machine).
The original Macintosh had "undo" functionality in its applications, right from the start.
The Apple IIGS also had "undo" functionality.
There may have been one or two individual applications before it (I don't know) but the Mac made "undo" ubiquitous.
Yes, MIT's Lincoln Reckoner had multiple-level undo/redo in 1968. That used a screen editor, so it would be the kind of undo you are talking about, however it was probably inspired by IBM's APL line-based workspace editor.
APL programmers had multiple-level undo/redo on their selectric typewriters around 1965. Each interaction was numbered, and you could select the number of the last interaction you wanted to keep. This would reset the entire workspace so that all variables, your program image, and options would be restored. This worked by saving the workspace each time a command completed, and was also useful for restoring sessions after interrupted connections.
Single-level undo appeared much earlier -- the first IBM teletype line editors in the late 1950s had single-level undo.
NI added undo to LabVIEW in the 5.0 release (ca. 1997) of the product. It was really funny how the marketing from NI revolved around that feature. "Now with UNDO!" You would think that promoting the introduction of a feature that is so ubiquitous in most other desktop software would be less than effective--that people would groan because they had expected it for so long. However, at one of their trade shows, the presenter mentioned the new UNDO and got a standing ovation.
It's not easy to implement. It's actually a lot of work. Suppose, for example, you're building a 3D animation system and every operation needs to be undoable. Every time you tweak a vertex, or intersect two polyhedra, or retesselate a primitive you need to have a way of undoing it. This isn't just a few lines of code. It means that every time you write some code to do anything you need to write code to undo it. This is a lot of work.
Doesn't it make you feel good to know that our freedoms are protected by politicans, lawyers and journalists.
Here's what one well known Academy Award winning 3D package does. Every command is an object. When you execute a command that object is stored in a 'history'. The command has two methods, a do() method and an undo() method. As long is the object remains alive it can undo or redo the associated operation.
Doesn't it make you feel good to know that our freedoms are protected by politicans, lawyers and journalists.
I remember a rudimentary CAD program for the Apple ][+, circa 1982 or 1983. I wish I could remember the name...
I personally first encountered "Undo" on the Mac in 1984. But this CAD program had a function... they didn't call it "commit." I don't remember the exact language they DID use.
The idea was that you never had to worry about making mistakes, because every action you took was tentative, and would be shown to you as a preview before taking effect.
So you'd give a command to draw a line, you'd see the line onscreen, and you could either accept it (in which case it became part of the drawing) or reject it (in which case it disappeared).
The weird thing about all this is that logically, it is exactly equivalent to an "undo" function.
And the even weirder thing is that while an "undo" function feels empowering and liberating... when the exact same function was presented as "tentative action, preview, accept/reject" it felt clumsy and laborious.
To me, anyway.
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