[luau] NEWS: Sherwin-Williams to use Linux Cash Registers

[Ray Strode]

Hi Scott.

> echo -ne "\\033\133\065\151"
> cat $*
> echo -ne "\\033\133\064\151"
Okay, I looked these escape sequences up at vt100.net and they do
exactly what you say they do.  The first one says, "terminal, please
redirect everything I tell you to your printer instead of your screen"
and the last one says, "stop redirecting to the printer and go back to
directing to the screen".  I played around with xterm and .Xdefaults a
bit and got it to work.
The X resourses that are needed are:

xterm*printerCommand: lpr
xterm*printerAutoClose: true 

where lpr is the printing program.  Since these output devices are
basically just line printers we could probably construct our own custom
lpr program if needed.

  Are your linux register boxen going to be running X?  I checked
whatever version of the kernel source I have laying aroudn on my
hard-drive (console.c) and the kernel's console vt's don't appear to
support those particular escape sequences.  I don't think it would be
too terribly hard to add that feature to the kernel tho (it's all
grouped in a pretty easy to follow set of switch() statements). There
may already be a patch on the net somewhere, or it may already be in the
kernel in a non-obvious [for me] spot.  I'll do more investigating if
you like.

> In Counterpoint certain codes are defined for this type of pole display 
> that insert themselves in the lpt stream and send the right data to 
> the pole and the rest to the printer.  
Interesting.  What are those codes?  When I looked in the vt102 user
manual, I didn't see anything to support printer selection (probably
because real vt102's and the like only had at most one printer per
terminal).

> It is this pass through and local file configuration that I am 
> not certain about, yet, with a pure linux register.
Me neither.  If the sequence that specifies which output it's going to
comes after the print sequence then we can just have our lpr scan for
that sequence and choose accordingly.  If it happens before the print
sequence, then we'll probably have to patch xterm to support it.  If X
isn't an option at all, then we'll have to patch console.c in the
kernel.  

> I know it is doable, but I have not tried, period.
Yea I think we'll be able to get it to work.  Although, I'll admit that
I've never done anything like this before.

--Ray