Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Posting-Version: version B 2.10.2 9/18/84; site wateng.UUCP
Path: utzoo!watmath!wateng!twholm
From: twholm@wateng.UUCP (Terrence W. Holm)
Newsgroups: net.arch
Subject: Re: dumber terminal device drivers
Message-ID: <2294@wateng.UUCP>
Date: Thu, 18-Apr-85 16:00:23 EST
Article-I.D.: wateng.2294
Posted: Thu Apr 18 16:00:23 1985
Date-Received: Thu, 18-Apr-85 23:25:14 EST
References: <327@piggy.UUCP> <2536@nsc.UUCP> <524@hou2d.UUCP> <429@dsd.UUCP> <2023@uvacs.UUCP> <172@ncr-tp.UUCP>
Reply-To: twholm@wateng.UUCP (Terrence W. Holm)
Organization: U of Waterloo, Ontario
Lines: 39
Summary: 

If someone attempts a device driver for `dumber terminals' on
Unix systems, I would suggest that they take a look at how
Data General has given AOS users a uniform one-line editor.

Programmers can use a routine, call it "SCREENREAD(line)", which
will retrieve one line from the users terminal. The advantage of
using this call is that the routine has a set of line editing
features built-in, this includes all of the common DELETE, 
NEXT_WORD, LAST_WORD, INSERT, GOTO_EOL, DELETE_EOL, etc. The
most powerful feature is that an old `line' may be specified
in the call, making the edits common with csh "!!" and "^p^r" 
extremely easy.

Once a `user' has learned the keystrokes for this one-line
editor, he knows how to interact with all programs which request
input of a line. This includes their visual editor, which
uses EXACTLY the same keystrokes while the user is within one
line. 

SUMMARY: Once a standard line-editing format has been specified
then all programs can use this one routine. This simplifies most
programs, and also eases the use of a system. The standardization
also helps improve performance because the device drivers can
contain special code for the known one-line editing characters.
This section of the device driver can also be moved to the
other end of the user/mainframe connection. Thus, we can get
optimization at the other end of a network, or built into
the non-dumb terminals (as has been done).

As opposed to a `general device driver', a Unix system could have
one which handles the line-editing characters of `vi'. And all
programs which decided to improve their performance could
use a new "get_edit_line()" call.

					Terrence W. Holm


AOS is an operating system supported by Data General
Unix is an operating system supported by AT&T