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Path: utzoo!henry
From: henry@utzoo.UUCP (Henry Spencer)
Newsgroups: net.micro
Subject: Re: terminal emulation
Message-ID: <7029@utzoo.UUCP>
Date: Wed, 6-Aug-86 17:38:00 EDT
Article-I.D.: utzoo.7029
Posted: Wed Aug  6 17:38:00 1986
Date-Received: Wed, 6-Aug-86 17:38:00 EDT
References: <2723@brl-smoke.ARPA>
Organization: U of Toronto Zoology
Lines: 17

> First of all, A terminal really need not scroll at 19.2K baud - Nothing
> can read that fast anyway...

More telling yet, no existing display updates the light pattern on the
screen that fast.  The fastest refresh I'm aware of on a common device
is 71 Hz on the 520ST.  Suns are 66 Hz.  Most terminals are 60 Hz or even
(shudder) 30 Hz interlaced.  Except for very unusual jobs, there is
absolutely no need to scroll the screen more than once in a screen-refresh
interval; the human watching will never see the intermediate state.  If
the screen is going to be scrolled several lines by the time of the next
screen update, then one can do the scrolling as *one* multi-line jump
and then fill in the empty lines at the bottom.  Doing this right is not
trivial, since it means looking ahead into the input stream to optimize
the handling of (e.g.) a linefeed, but it is possible.
-- 
				Henry Spencer @ U of Toronto Zoology
				{allegra,ihnp4,decvax,pyramid}!utzoo!henry