Disgusting kernel hack

tjt at kobold.UUCP tjt at kobold.UUCP
Thu Feb 2 01:49:22 AEST 1984


The problem with using a terminal-based pager (e.g. "hold-screen mode"
on VT52's and lookalikes) is that it halts every 24 lines, need it or
not.  A typical pager built into the system will only pause if there has
been a screenful of output since the last input wait.  This accomodates
Dennis Ritchie's interactive mode (the user types a line or two, the
computer types a line or two, the user types another line ...) without
forcing a pause every 24 lines.

Someone proposed a terminal "hold-screen mode" that is reset whenever
the user types a key.  This is *not* the same since I don't want
typeahead to thaw my page mode, and only the OS knows when I'm in input
wait.  Indeed, some care should be taken in a kernel pager to leave
typeahead undisturbed (at least for the simple case of pausing and
continueing -- aborting the output should probably flush the typeahead).
-- 
	Tom Teixeira,  Massachusetts Computer Corporation.  Westford MA
	...!{ihnp4,harpo,decvax}!masscomp!tjt   (617) 692-6200 x275



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