Undo History - Why limit it? [closed]

1. Why is there an undo limit?
2. What is undo history?
3. How is undo implemented?

Why is there an undo limit?

There is no UX reason to limit undos. The reason undos are limited are due to hardware and software limitations (which were greater in the past than today). Save this answer.

What is undo history?

The Undo History window displays a list of all actions that can be undone. The most recent editing operation, which will be the first to be undone, is selected.

How is undo implemented?

To implement Undo , you work backward from the tail of the linked-list, using a 'current-node' pointer or index: where the change was insert , you do a delete but without updating the linked-list; and where it was a delete you insert the data from the data in the linked-list buffer.