Messages in this thread |  | | From | (H. Peter Anvin) | Subject | Re: scrollback | Date | 27 Oct 1996 03:39:30 GMT |
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Followup to: <3272A0FE.52193236@uiuc.edu> By author: Keith Rohrer <kwrohrer@uiuc.edu> In newsgroup: linux.dev.kernel > > 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. >
It's not bad at all, having written programs that do exactly that. It is only that currently, kernel memory is not swappable. I am suspecting it is getting unavoidable to add swappable kernel memory; there are indeed a number of features (like tmpfs) that cannot be reasonably done without it.
As far as the console, though, there is an alternative: consoled. There are simply features that do not belong in kernel space (dynamic font generation comes to mind.) However, it is perfectly reasonable to do a console manager in user space, using "graphics" (i.e. software-managed) console mode and raw keyboard mode; and, of course, PTY's.
-hpa -- Not speaking for Transmeta in any shape, way, or form.
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