From time to time, Emacs automatically saves each visited file in a separate file, without altering the file you actually use. This is called auto-saving. It prevents you from losing more than a limited amount of work if the system crashes.
When Emacs determines that it is time for auto-saving, it considers each buffer, and each is auto-saved if auto-saving is enabled for it and it has been changed since the last time it was auto-saved. The message ‘Auto-saving...’ is displayed in the echo area during auto-saving, if any files are actually auto-saved. Errors occurring during auto-saving are caught so that they do not interfere with the execution of commands you have been typing.
|• Files:||The file where auto-saved changes are actually made until you save the file.|
|• Control:||Controlling when and how often to auto-save.|
|• Recover:||Recovering text from auto-save files.|