I was at Fry's and picked up what i guess is the only non-hp RPN made since the late 70's. Mike Davis let me put a photo of it on his site and if you want; you can see it at http://www.msdsite.com/forums/upload.php?upload=zoom&pid=302

Let's all hope for an Aurora / hp 15c clone next.

What is the overall quality of this calculator (keyboard, display,...) ?

All the best

Pierre

Here in Brazil it is sold for about US$53 (R$150), there is a link to an auction (in portuguese):

http://www.mercadolivre.com.br/jm/item?site=MLB&id=13231402

Pierre Brial on 19 Oct 2003, asked:

What is the overall quality of this calculator (keyboard, display,...) ?

None of it is traditional HP quality, but it is not bad.
Rather soft keys, excellent big and contrasty display.
The worst design feature IMHO is that when the lid is
closed, it is easy to press it above the general area of
the ON button, and turn the calculator on. Since the
display is hidden, you will not see that you have turned
it on, and so you can do this repeatedly and run down
the battery. My other complaint is that the keyboard
is evidently taken from a different Aurora model, so
the right-shift (orange) key is labelled "Alpha", though
it does not provide any alpha features :-)

But, yes, a non-HP RPN model at last, and let's indeed
hope for an HP-15C clone next :-) But it's only a hope.

Many thanks to Dave Hicks for helping me get one to
Europe!

Wlodek

Thank you Wlodek, for these informations.

I just received your book, it's great !

A bit difficult to order it from France, but I finally succeed.
Very good job, congratulations ! I read it like a novel, but faster.

All the best

Pierre

In the early 1970s, HP bought up ALL the RPN-type patents from the old office-machine companies. This is why my baby, the National Semiconductor 7100 calculator, was algebraic and not RPN when it was under development in 1976/1977. This is also the major reason why nobody else in the entire world has ever dared to infringe HP's RPN patents now that they have bought them all. I just wonder if Aurora is named for the (rumored) Aurora space-plane, which has supposedly replaced the U-2, and the SR-71, and which is believed by many to fly faster than Mach 8. Mach 8 may well be the speed required to outrun Hewlett-Packard's herd of lawyers.

Patents expire after 20 years (I think).

Hello Mr Chumbley.
"...my baby, the National Semiconductor 7100 calculator..." !?
Dare I ask you were in some way involved in the design of this one ? I'd be *VERY* (major understatement) interested in any information regarding this machine. Was there any prototype built ? Blueprints ?
Thanks.

Old patents died 17 years after issue. New ones die 20 years after initial fileing.

Isn't/Wasn't it possible to renew patents once for an additional 17-/20-year period? If so, does anyone know how to find out whether a particular patent has been renewed?

One can always do a patent search, costs money though.

You can search for free (I've done this extensively):

www.uspto.gov/patft/index.html

Regards,

Bill

You cannot renew your patent. At one time people used to be able to play the "reissue" game where you added something to the patent to keep in in paperwork limbo. Since old patents did not start their 17 year clock until they were issued, this effectively extended their lives. Really sleazy people kept patents alive for over 40 years. When the revolution comes... I have a wall...