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HP Forum Archive 05

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New "unknown" HP-71B command discovered.
Message #1 Posted by Reinhard Hawel on 1 Apr 2001, 10:12 p.m.

Hi folks. As I found out in my research of the HP-71B system, there's a non-described function without arguments in the HP-71B ROM.

It's name is "MEMORY" and it returns the number 0 or one for unknown reasons. Maybe this is a check for HP, if the systems memory has been correctly implemented in this particular unit.

You can check it by just starting the system and entering "MEMORY". There are some other functions too: "MEMORY0" - "MEMORY9", but their reason is unknown til now. They all behave like "MEMORY"

      
Re: New "unknown" HP-71B command discovered.
Message #2 Posted by Ex-PPC member on 9 May 2001, 2:23 p.m.,
in response to message #1 by Reinhard Hawel

Your message being dated April 1st, it's blatantly obvious it's intended as an "April's Fool" joke.

Anyway, for those people who didn't realize that, and are puzzled by your "MEMORY" command, let's explain what's happening: MEMORY is being interpreted by the BASIC line interpreter as "MEM OR Y".

BASIC looks for a real MEMORY statement. It finds none, then parses the line. MEM is recognized as a valid numeric function who returns the amount of available memory. Then, OR is recognized as a valid boolean operator, and after that, Y is recognized as a legal variable.

So, the complete MEM OR Y is a perfectly legal expression, if weird. Of course, MEMORY0 to MEMORY9 are interpreted likewise, just using variables Y0 to Y9 instead of plain Y.

I saw this old joke many years ago, in a book by Joseph K. Horn titled something like "Get the most from your HP-71B" or so.

            
Re: New "unknown" HP-71B command discovered.
Message #3 Posted by Reinhard Hawel (Austria) on 10 May 2001, 11:27 a.m.,
in response to message #2 by Ex-PPC member

Yes, you're right. It was an April fools Joke.

I didn't read Joe Horns book. I discovered the function abt. 1985 and fooled a lot of guys then. You can see the correct function, when you enter MEMORY into a program and look at that line afterwards.

Anyway, I got one email from a guy who was surprised by the fact, that there are some undiscovered commands even now.

I also got an email from one person, who already knew it.

You can be sure, that all my other messages here on the board are no meant to be a joke.


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