Re: ??==Delete key only backspaces w/o delete from Telnet in Mac OSX Terminal

From: Fred Kleinsorge (my-last-name_at_stardotzko.dec.com)
Date: 09/08/03 

Date: Mon, 08 Sep 2003 15:01:05 GMT

"Thomas Dickey" <dickey@saltmine.radix.net> wrote in message
news:bjcku9$lrb$2@news1.radix.net...
> In comp.os.vms Fred Kleinsorge <my-last-name@stardotzko.dec.com> wrote:
> > On VMS, with a PC keyboard (a non LK450/411/463) you can press (and
hold)
> > LOCK and Fn to get Fn+10 (F1 -> F11, etc). Lock will be flipped back to
the
> > original state. It's the VT500 trick.
>
> I'd think that's inconsistent with DECUDK, which uses a shifted function
> key to get the string that is assigned with that escape sequence. In
> XFree86 xterm I use a control-modifier rather than shift-modifier.
>

I don't have DEC Std 70 around handy, but I'm not sure there is a conflict.
In this case, LOCK (not shift) is being used as a single-shot combination
key. It won't interfere with SHIFT, or the state of the SHIFT or LOCK. I
ripped the mechanism off from what the VT525 does.

In this particular case, at the device driver level IF (and only if) the
keyboard is a PC-layout keyboard when a function key (F1-F10 and Keypad +)
are pressed and IF the lock key is in the down (pressed) state, then the key
is translated to Fn+10 (or KP+ -> KP-). The state of the shift/lock state
is then flipped back to what it was prior to the lock key being depressed
(and the lock key release is ignored later on). What gets sent up to the
server is the keycode for the missing key.

The DECterm user defined key stuff is handled much farther up the stack.

This stuff has been in the VMS code since the first PC-kb based system we
shipped (the Jensen) in the early 90's.

I've generalize this in the USB keyboard code, so that a user can create a
keyboard translation table and enable this feature or disable it, and
program explicitly the LOCK/KEY combinations and the resultant key code.