HP 87 Easter Egg - Games in Extended Mass Storage ROM

Plug the EMS ROM into an HP 87 (or HP 86).

Type TRUJUGI and/or FIRJEN as commands - simple dodgem game appears.

This quite an early Easter Eggs, roughly 1985-7?

Note from the game author (Everett Kaser):

I was working in the R&D lab at the time, and a good friend was working in marketing. This company (Structured Software Systems, I imagine, tho I don't remember the name for sure) approached HP about getting a custom ROM made with their own code in it. HP was happy
to (pay the price, get whatever you ask for). Well, I was deligated the job of taking their bits and making the release tape to send off
to the ROM factory. I noticed, though, that the code they wanted in the ROM only took up maybe 1/2 of the available 8K bytes space.
And I had a few little games around that I'd written in my spare time... I thought, "What the heck? What they don't know won't hurt
anyone, right?" (I was young and foolish... :-) So, I added the binaries of a couple of the games and gave them ridiculous statement names to invoke them (so that they wouldn't ever collide with anything else in the name space). All was well until the ROMs came back and were sent to the purchaser. One day my friend from marketing wanders into the lab to my desk and asks, "Say, Everett.... you didn't happen to put anything extra into those ROMs did you?"

Well, with a sheepish grin, I had to admit what I'd done. It turns out that the ROM purchasers had apparently written some binary programs that, rather than calling the code in the ROMs through the normal vector tables, jumped DIRECTLY into the ROMs to a specific address... and adding the two new statement names to the name tables
and their corresponding addresses to the address tables had (because those tables are always at the top of the ROM's address space) pushed
everything else down a few bytes.


Oh well, all they had to do was recompile their binaries with the new addresses and all was well. Fortunately they didn't complain
(apparently), as I never heard any more about it.

And that's the story.

Best wishes,


User Rating:
  8.8/10 with 13 votes
Contributed By: John on 09-04-2002
Reviewed By: Webmaster
Special Requirements: EMS ROM (00087-15013)
Please correct this Egg if you see errors.

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