Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!henry
From: henry@utzoo.UUCP (Henry Spencer)
Newsgroups: net.unix-wizards
Subject: Re: Pagination in TTY driver
Message-ID: <5937@utzoo.UUCP>
Date: Fri, 6-Sep-85 15:32:52 EDT
Article-I.D.: utzoo.5937
Posted: Fri Sep  6 15:32:52 1985
Date-Received: Fri, 6-Sep-85 15:32:52 EDT
References: <2067@ucf-cs.UUCP> <363@cuae2.UUCP> <2423@sun.uucp>
Organization: U of Toronto Zoology
Lines: 35

>    At caltech we have a network that lives between most computers and
>    most terminals, now unfortunately the network uses ^S/^Q (of course)
>    and any ^S, ^Q you type on your terminal will go to the network
>    not to the computer.  So putting pagination in the tty driver
>    really confuses novice users, the documentation says that pressing
>    ^Q gets things started again, but it doesn't...

As has already been pointed out, using ^Q to restart paging is a terrible
mistake because it is increasingly necessary to reserve ^S^Q exclusively
for low-level flow control.  Don't confuse this implementation mistake with
a general problem with the concept.

> Time for a third point of view here.  Pagination belongs in the terminal!
> ...[the terminal knows best what is happening on its screen]...
> While I'm at it, the terminal is also where history belongs...

This is 100% correct.  But if one does not have such terminals, that is not
cause to give up in despair.

> We have such a tty driver on an 11/34 running Xenix 2.?.  In 'normal' use
> with keyboard input, one does not see the paginator, only when a program 
> is producing reams of output.  It was a pain in the neck to find a process
> blocking on tty output when one didn't want the paginator...
> The problem is, that version of Xenix does not have Berkley job control.
> The times I've wanted to.. [use job control to turn paging off/on for a
> particular already-started process]

I'm not sure whether I mentioned this earlier:  it is *important* to have
a clean and simple way of turning paging off temporarily, to solve this
exact problem.  Having a single special character that turns paging off
until the next input character works wonderfully well -- you can turn the
paging off for a ream of output, and it turns itself back on automatically.
-- 
				Henry Spencer @ U of Toronto Zoology
				{allegra,ihnp4,linus,decvax}!utzoo!henry