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Path: utzoo!dciem!nrcaer!xios!greg
From: greg@xios.XIOS.UUCP (Greg Franks)
Newsgroups: comp.unix.questions
Subject: Re: Multiscreen on Unix
Message-ID: <317@xios.XIOS.UUCP>
Date: Wed, 10-Jun-87 10:01:31 EDT
Article-I.D.: xios.317
Posted: Wed Jun 10 10:01:31 1987
Date-Received: Tue, 16-Jun-87 00:37:30 EDT
References: <910@minnow.UUCP> <5942@brl-smoke.ARPA> <103@rb442.UUCP> <20550@sun.uucp>
Reply-To: greg@sdn.UUCP (Greg Franks)
Organization: XIOS Systems Corporation, Ottawa, Ontario, Canada
Lines: 30

In article <20550@sun.uucp> guy@gorodish.UUCP writes:
>In the particular case of a PC, there may be tricks you can play with
>multiple screens that won't work with windows.  The programs running
>in the "active" window can be given direct access to the screen, and
>when switching screens you can just copy the entire screen image to a
>holding buffer; you could just freeze programs running in inactive
>windows, and thus not have to worry about multiplexing input or
>output.

PC's use memory mapped output for the console.  To write to the screen,
simply write to memory.  The screen controller attends to the rest of
the nonsense.  To switch screens, simply point the screen controller at
a new place in memory.  No multiplexing, synchronization, or copying is
needed.  I think that implmenting something like this on a
run-of-the-mill terminal may be a bit difficult (and a wee bit slow
too). 

Microport does not freeze output going to a "virtual console".  Thus,
you can run a "tar cv..." on one virtual console while doing something
else on another.  In fact, one could think of the console proper as
being four terminals in the package of one. 

And if you really wanted to get inspired, you could have multiple
windows in each of the virtual consoles - yeah - that's the ticket! :-)


-- 
Greg Franks     (613) 725-5411          "Vermont ain't flat"
{net-land}!utzoo!dciem!nrcaer!xios!greg
(Other paths will undoubtably work too - your mileage will vary)