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From: Stephen Clark <Stephen.Clark@seclark.us>
To: James Cloos <cloos@jhcloos.com>
Cc: Jan Engelhardt <jengelh@linux01.gwdg.de>,
	Pavel Machek <pavel@ucw.cz>, James Lockie <bjlockie@lockie.ca>,
	Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [Fwd: escape key]
Date: Mon, 18 Dec 2006 09:02:55 -0500	[thread overview]
Message-ID: <45869F8F.2020009@seclark.us> (raw)
In-Reply-To: <m3bqm20zj8.fsf@lugabout.jhcloos.org>

James Cloos wrote:

>>>>>>"Jan" == Jan Engelhardt <jengelh@linux01.gwdg.de> writes:
>>>>>>            
>>>>>>
>
>Jan> HOWEVER, unix people probably _had a reason_ to make ESC generate
>Jan> part of what function keys do.
>
>You are looking at it backwards.  The Escape key generates an ASCII
>escape.  The funtion keys (including the cursor keys) generate escape
>sequences because the vt100 won out the title as the most ubiquitous
>async serial terminal, and linux devs chose to have the console be
>(mostly) vt100 compatable.  As xterm, et al had done before.
>
>The terminals (the actual hardware) used ASCII, so it was normal to
>use Escape to initiate the sequences used by the function keys.
>
>And that concept goes back a *lot* longer than unix.  (Hmm.  I can't
>remember.  Did TOPS-20 or its predecessor have glass terminals in the
>day?  I did get to use a DEC paper terminal a couple of times, but
>that was connected to a VMS box back in the '80s; most of the time it
>sat in the corner collecting dust....)
>
>At any rate, given that Escape was used to initiate sequences sent to
>the terminal for funtions such as moving the cursor around the screen,
>clearing rows or cols, et al it must have only seemed natural to also
>have it initiate sequences /from/ the terminal which did not fit into
>standard ASCII.  That was after all Escape's purpose in the ASCII std.
>
>If you do want to change the console's terminal emulation, a good
>first step would be to check whether any existing terminal already
>uses something other than Escape to initiate function key sequences,
>and, if so, promote that as the alternative to vt100-esque emulation.
>
>Finally, note that the reason vt100 was chosen for the console was to
>make it more useful for users who were physically at a linux box, were
>logged in on the console, and from there logged in to remote servers.
>That does remain something which the console *must* support.
>
>-JimC
>  
>
Also ansi came along and pretty much put their blessing on what DEC had 
done and made the
escape sequences a standard.

Steve

-- 

"They that give up essential liberty to obtain temporary safety, 
deserve neither liberty nor safety."  (Ben Franklin)

"The course of history shows that as a government grows, liberty 
decreases."  (Thomas Jefferson)




      reply	other threads:[~2006-12-18 14:02 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-12-14  1:04 [Fwd: escape key] Sergio Monteiro Basto
2006-12-14  5:41 ` Randy Dunlap
2006-12-14  6:04   ` James Lockie
2006-12-16  8:45     ` Pavel Machek
2006-12-16 18:34       ` Jan Engelhardt
2006-12-17  0:51         ` Stephen Clark
2006-12-17  9:40           ` Jan Engelhardt
2006-12-18  1:21         ` James Cloos
2006-12-18 14:02           ` Stephen Clark [this message]

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