The virtual consoles are there, and seem to work quite well.

The virtual consoles
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The virtual consoles are implemented in the display memory for now. This
means that MDA users are just out of luck, because it has no extra memory.
On the other adapters, the max number of vcs is:

	bytes_of_videomem / ( width * height * 2 ) - 1

This gives, for example, on the CGA

	16384 / ( 80 * 25 * 2 ) - 1 = 3.096 = 3

The currently visible screen contents are copied to the address which is
displayed by the 6845. The stored screens are at addresses starting from
the end of the visible page, rounded up to the nearest 2048 (40 x 25),
4096 (80 x 25) bytes, or 8192 (80 x 43 or 80 x 50) bytes.

When writing on the visible screen, the writes go through it to the other
copy of it as well, so no need to copy back the current screen when
switching to another.

It is possible to write to a non-visible screen using Console_write().
The screen to write to is determined by the minor number in inode, ie
MINOR( inode->i_rdev ) == 0 writes to the first vc.

Everything done with con_charout() will be written to the currently
visible screen.

A new function, Console_set_vc( int new_vc ), is exported to do the task.
xt_key.c was modified to use this new func, when alt-fn is pressed.
