Re: scrollback
Keith Rohrer (kwrohrer@uiuc.edu)
Sat, 26 Oct 1996 18:38:38 -0500
PC-Ace@iactiva.cl wrote:
>
> >Better yet, why not have it saved in a file?
> >/var/run/scroolback/tty1, tty2, and so on...
>
> NO! I mean, I'm not even sure it can be done, but if it could, wouldnt
> it be HORRIBLY slow?!? Imagine the kernel doing a read/write EVERY time
> you change your VC. This would certainly be a pain in the ass,
> especially when you do it a lot (like I do). And even worse with slow
> disks/controllers.
Try switching between a "normal" VC and a VC in graphics mode (e.g. X)
and back sometime. That overhead is (1) copying the necessary amount of
video RAM (2-4 megs total) to + from virtual main memory (with
associated pages getting written out to the swap space), and (2)
possibly paging in code to write to the backing store rather than to the
screen. It's not too bad for a full graphics screen if you don't need
to swap it in, and the tails of the little scrollback buffers would fit
in the cache much more easily than a meg or two of X screen...
It's not as bad as you think.
Keith
--
"It moved faster. I swear, they are evolving right before my eyes. If
you see something this big, with eight legs coming your way, let me
know;
I have to kill it before it develops language skills."
--- Ambassador Londo Mollari, in 'Sic Transit Vir' (Babylon 5)