HP 65/25 shout-out in interview with Paul Lutus


Paul Lutus designed electronics for the NASA Space Shuttle ...



I read many years ago that Paul Lutus wrote his own OS for the Apple []. He seems to be one sharp dude.

It was nice to hear about Lutus again. For many years I wondered what happened to him.



In 1977 I was looking through my local library for anything about microcomputers and came across an article in Popular Electronics by Lutus describing his game program Space Flight for the HP 25. In the game you control the thrust of a spacecraft orbiting two planets and try to land on one. A 2-D, 3-body lunar lander game!

I wanted to play it on my shiney new SR-56 so I taught myself RPN and converted it. What fun! I still have my listing and a photocopy of his. To compare: the 25 version uses 49 steps and 7 registers; the 56 version uses 92 steps and 10 registers.

Last year I emailed Paul and reminded him of that article. He said he wrote several popular articles back then. I encouraged him to post to this forum but I haven't seen anything.


To compare: the 25 version uses 49 steps and 7 registers; the 56 version uses 92 steps and 10 registers.

In 1977, I was writing programs for both a HP-67 and a TI-59 for real operational use on the nuclear submarine on which I was stationed. I found that the RPN version would typically require only about 60 percent of the memory assets of the AOS version. Your example independently confirms that estimate.

Possibly Related Threads...
Thread Author Replies Views Last Post
  Strange HP 25 Problem (Repair) Onur Ilkorur 5 1,862 12-06-2013, 05:13 PM
Last Post: Onur Ilkorur
  HP-25 Wayne Selway 1 812 11-22-2013, 12:58 PM
Last Post: Michael de Estrada
  HP-65 short circuit Ignacio Sánchez 2 1,035 10-22-2013, 08:27 AM
Last Post: Ignacio Sánchez Reig
  Interesting Base Conversions - Porting a 1975 HP 25 Program to the HP 35S Eddie W. Shore 1 890 10-13-2013, 07:49 PM
Last Post: BruceH
  HP-65 Video Tapes - Anyone have a Copy? Bill (Smithville, NJ) 3 1,123 10-09-2013, 07:40 PM
Last Post: Paul Berger (Canada)
  Using your HP-65 as a clock! Don Shepherd 24 4,384 10-08-2013, 11:53 AM
Last Post: Don Shepherd
  HP-65 to kill... Benoit Maag 11 2,303 08-15-2013, 08:18 PM
Last Post: Jake Schwartz
  HP-25/25C Potential Matt Agajanian 14 3,079 07-17-2013, 02:57 AM
Last Post: Matt Agajanian
  For sale: HP 25C and Stat Pac 2 for HP 65 Michae Altmann 1 753 04-21-2013, 01:24 PM
Last Post: Raymond Del Tondo
  Repair my HP 65 motor? Michae Altmann 1 785 04-13-2013, 10:03 PM
Last Post: aj04062

Forum Jump: