Follow the steps detailed below. If you don’t want to get and compile the bdfresize package yourself, you can skip to step 3 and download a magnified font instead of creating it.

1. get cursor.bdf, the source of the cursor font, from some X distribution, e. g. from ftp://ftp.x.org/pub/R6.3/xc/fonts/bdf/misc/cursor.bdf (if you don’t find it there try an archie search or get it from my copy).
2. get, compile and install the bdfresize package from ftp://ftp.cs.titech.ac.jp/X11/contrib/Local/bdfresize-1.4.tar.Z (or from my copy):

        zcat bdfresize-1.4.tar.Z  | tar xf -
        cd bdfresize-1.4
        xmkmf
        make
        
   

   On Linux you probably have to use:

        make CCOPTIONS='-include /usr/include/bsd/bsd.h' clean all
        
   

3. create a directory and install a magnified cursor font in it (magnification factor 2 in this example):

        mkdir $HOME/fonts
        bdfresize -f 2 cursor.bdf | bdftopcf >$HOME/fonts/cursor2.pcf
        mkfontdir $HOME/fonts
        
   

   I have prepared some cursor fonts with the following magnification factors: 1.5, 2, 2.5, 3, 4, 5, 6, 7, 8 and 16. You can download one of them an copy it to $HOME/fonts if you don’t want to use bdfresize.

4. modify your .xinitrc or .xsession file: before any X client (that uses cursors) is started the following commands must be executed:

        xset +fp $HOME/fonts
        xsetroot -cursor_name X_cursor
        
   

5. leave your X session and restart.

That’s it—now all mouse cursors should have doubled in size.