Move cursor to old position after scrolling

Question

I often want to edit text in say line 200 of a file, but while doing this I need to look at say line 100, so I scroll to line 100. Is there a way to quickly jump back to line 200 after scrolling? Is there a possibility to configure a jump mark that is update with every movement except scrolling?

'' doesn't seem to work.

EDIT: An answer should preferably describe a way to do what I'm asking. That is move to the position the cursor had before scrolling, without having to do anything beforehand.
If you have advice on other ways to solve the general problem, e.g. using splits or setting a mark before scrolling feel free to write a comment.

Answer 1

Go back in the same file

Mark your current position with mm , move around, go back with 'm or `m.

Go back to last insert position in the same file

`^

Go back to last insert position and continue in insert mode

gi

Go back accross files

Mark your current position with mM , move around, go back with 'M or `M.

Answer 2

First, instead of scrolling, try :100 or 100G; then the ` mark will work.

Second, if viewing multiple parts of the same file, why not :[v]split it? Splits are perfect for multiple views of the same file.