Subject: Re: PCVT/virtual consoles
To: None <current-users@NetBSD.ORG>
From: der Mouse <mouse@Collatz.McRCIM.McGill.EDU>
List: current-users
Date: 05/08/1995 11:13:02
> For instance, it should be easy and very fast to provide a text-only
> virtual terminal emulation on PC's, because of the fact that they've
> got a text mode built into their video cards...  That'd be a lot
> harder on something like a sparc, which doesn't have built-in text
> mode.

It's actually only a little harder; the only thing is that rather than
just poking a couple of bytes of video ram to draw a character, you
have to blit a bitmap into the framebuffer.

And of course, if you're going to virtualize the emulator, the amount
of stuff you need to save/restore goes up.  (Unless, of course, you
maintain a memory area holding displayed characters in a compact form,
and re-render when restoring.  IMO this would be more work than it's
worth, and probably has undesirable semantics to boot.)

The hard part, of course, is making the switch work with things like
the X server.  To do this right you would have to arrange that when
someone mmap()s the framebuffer, it's recorded so than when switching
away, you can point that process at the saved memory area.  I would
imagine most of the hard work of this has been done for the x86 port.

					der Mouse