Updating the swapfile
The swap file is updated after typing 200 characters or when you have not typed anything for four seconds. This only happens if the buffer was changed, not when you only moved around. The reason why it is not kept up to date all the time is that this would slow down normal work too much. You can change the 200 character count with the 'updatecount' option. You can set the time with the 'updatetime' option. The time is given in milliseconds. After writing to the swap file Vim syncs the file to disk. This takes some time, especially on busy Unix systems. If you don't want this you can set the 'swapsync' option to an empty string. The risk of losing work becomes bigger though. On some non-Unix systems (MS-DOS, Amiga) the swap file won't be written at all.
From this I have a few questions:
Does this mean Vim autosaves your work from time to time?
"After writing to the swap file Vim syncs the file to disk." What does this mean? Is this refering to the file being written first to memory and then to the disk or is it something else?
Say I'm taking class notes: I write fast and there's little need for me to leave Insert mode. But many times I change to Normal just to save my work. Do I need to do this or does Vim make sure that most of my work is saved even if I don't leave Insert mode?