Question: I used ctrl-6 to jump between two files and compare these two files page by page, But each time when I switch back, the page content is changed. That is, a new page with previous cursor line in the middle of screen now is shown instead.

Is there a way to keep the page position in the screen unchanged when I switched back.

Thanks a lot!

Answer: 
May I suggest using tabs (`C-PgUp` and `C-PgDn` to switch)?

You can always start by doing `C-w``s``C-^``C-w``T`

Otherwise see this odler answer of mine for hints on restoring cursor positions: 

* [After a :windo, how do I get the cursor back where it was?](https://stackoverflow.com/questions/9984032/after-a-windo-how-do-i-get-the-cursor-back-where-it-was/9989348#9989348)
* [Vim buffer position change on window split (annoyance)](https://stackoverflow.com/questions/9625028/vim-buffer-position-change-on-window-split-annoyance/9626591#9626591)
This might not be what you're looking for, but just in case: For a different approach to the task you're doing (visually comparing two files), see `:help scrollbind`. You would do `:set scrollbind` in two side-by-side windows and open one file in each, then scroll through them together, linked. See also `vimdiff` for even more functionality.