Messages in this thread |  | | | Date | Thu, 14 Mar 1996 13:48:49 GMT | | From | Simon Tatham <> | | Subject | Re: scrollback and VT switching |
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>> After switching from the current VT to another one and back, scrollback >> no longer works for the original VT. Is this a bug or a feature? :-) > >To my knowledge, this has never worked (at least not for me). Also, >sometimes the number of lines of scrollback vary. I assume this is >because the buffer is based on the total number of characters and not on >the number of lines?
Presumably you're using a 1.2 kernel then?
The scrollback used to be done as nothing but a side effect of the way the scrolling was done: scrolling up by one line is accomplished by moving the start-of-screen pointer *down* by a line. This allows everything from the top of VRAM to the current screen position to be used as scrollback, at no extra cost. However, if you try to get scrollback *just* after the screen position has had to be wrapped back round to the top, you don't get a lot of it at all.
From 1.3.3 onwards, the scrollback was improved (by me) to give the small enhancement that *all* the VRAM not in use by the current screen is available for scrollback: so the number of lines of scrollback should remain constant, or virtually so. (There are complications when the screen position is very near one end of VRAM.)
Hope this helps
/ o Simon Tatham E-mail to: sgt20@cam.ac.uk \ I /\/\ O /\/ http://callisto.girton.cam.ac.uk/users/sgt20 / ~~~~~~~~~~~~~~~~~ Trinity College, Cambridge, CB2 1TQ, England
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