VIM provides the ability to edit multiple windows to simplify complex editing tasks. Vim's multiple windows are not meant to start multiple vim instances on a terminal.
Start multiple window edits
Vim's multiple windows are dynamic, you can open multiple windows when you start editing, add new windows whenever you work, or delete a window.
$ vim-o file1 File2 opens an edit session, which is displayed as a horizontal split window with one file occupying one window.
$ vim-o file1 File2 is the same as above, but is a vertical split between two halves of the window
As shown in the following illustration:
If the screen is not enough to accommodate all the windows, then the first file will occupy most of the window, the remaining window is loaded into the buffer, temporarily can not see, but can still be used.
-O followed by a number n, which is open in the form of a pre-allocated window:
$ vim-o5 file1 file2 will be allocated 5 identical Windows, 3 of which are idle