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From: firth@sei.cmu.edu.UUCP
Newsgroups: comp.arch
Subject: Re: paging in the terminal driver
Message-ID: <3018@aw.sei.cmu.edu>
Date: Wed, 28-Oct-87 09:07:36 EST
Article-I.D.: aw.3018
Posted: Wed Oct 28 09:07:36 1987
Date-Received: Sat, 31-Oct-87 04:29:33 EST
References: <573@elxsi.UUCP> <682@its63b.ed.ac.uk> <796@quacky.UUCP> <421@nuchat.UUCP> <550@mcrware.UUCP>
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Reply-To: firth@bd.sei.cmu.edu.UUCP (Robert Firth)
Organization: Carnegie-Mellon University, SEI, Pgh, Pa
Lines: 21
Keywords: output pagination

For what it's worth, here's what we did in IAS on the PDP-11.  (Well,
my good friend and systems person Alan Stout wrote the code, but I
contributed the low cunning.)

Paging was indeed done in the terminal driver; after 20 lines (or
whatever) it stopped until you typed ^Q.  The frills were what made
it work:

(a) we reset the count whenever a new program attached to the terminal.
    so you didn't get any hangups in normal user dialogue

(b) we reset the count at ^S, so the DEC "standard" ^S/^Q protocol could
    still be used, and you always got a full page after ^Q

(c) we ignored the count if there was anything in the typeahead buffer,
    on the principle that a user who had typed the next command didn't
    really care what the current program was saying.  So you could go
    type a single space and go for coffee (and even erase the space when
    you got back)

The result was far more satisfied users than dissatisfied ones.