Re: SMALL bug

Bryn Paul Arnold Jones (
Sat, 26 Oct 1996 01:18:36 +0100 (BST)

On Fri, 25 Oct 1996, Charlie Ross wrote:

> Not even really a bug, just a curriocity...
> Console in text mode...
> for some reason, about one in every 100 times the console scrolls, it wont
> scroll cleanly, ie,
> I will ocaccionally see .'s on the right hand of the screen, when I
> scroll back to see if its really there, it isnt...
> and somtimes it happens when I am scrolling just one line...
> Any suggestions?

Known problem, it happens when the screens just being scrolled, and the
screen update catches us in the act ....

> PS... while we're on the console... is there any way to make the scroll
> back buffers stay, even when you switch to another tty and back?
> Thats kind of a bother too...
> -Chuck

It would be hard, currently it works like this:

Fill the screen starting at the top of the video memory, keep going down
filling the next line, and the next .... This works because we just move
the top left of the screen down (and are sometimes cought ;), we start
over when we get to the bottom.

Shift-PageUp just moves the top left of the screen back a bit, so there is
just a psudo scroll back buffer, it dosn't actually exist. At a VT
switch, only the visable screen is saved, as it's a fixed size, starting
at the current top left, going on for width*hight chars.

Where as the scroll back buffer is of unknown lenth (can even have looped
over), starting at an unknown place, going on for width*(n lines). See
the problem ?

> (717)-337-8212

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