Re: Blank from keyboard

Geert Uytterhoeven (Geert.Uytterhoeven@cs.kuleuven.ac.be)
Fri, 10 Oct 1997 15:16:18 +0200 (CEST)

On Fri, 10 Oct 1997, Matthew Kirkwood wrote:
> > When will we get decent scrollback buffers
> > (independent for each VC, with 'screen' like
> > copy and search)?
>
> Ask the GGI crew about the independant scroll thing.
> They've got it already. About the other bit -- it's
> really not a kernel issue. We might need some new
> /dev/tty* ioctls to cope with the scrollback buffer,
> though.

Most people don't want scrollback buffers for all VCs in kernel space, because
it would consume a lot of precious unswappable memory.

Example: 80x50 text console, 200 lines (4 screens) scrollback, 8 VCs:

80x50x4x8 = 128000 characters = 256000 bytes

And then we don't have unicode support and a separation of attributes (bold,
underline, italics, ...) and text colors yet :-)

That's why the current scrollback scheme survives:

(1) it's a (non-portable) VGA hack, but
(2) it doesn't require extra memory

Greetings,

Geert

--
Geert Uytterhoeven                     Geert.Uytterhoeven@cs.kuleuven.ac.be
Wavelets, Linux/{m68k~Amiga,PPC~CHRP}  http://www.cs.kuleuven.ac.be/~geert/
Department of Computer Science -- Katholieke Universiteit Leuven -- Belgium