[HN Gopher] Retro-tech HP-25 Calculator
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       Retro-tech HP-25 Calculator
        
       Author : pbrowne011
       Score  : 32 points
       Date   : 2024-04-24 00:41 UTC (1 days ago)
        
 (HTM) web link (github.com)
 (TXT) w3m dump (github.com)
        
       | eschneider wrote:
       | It has a monitor! I take geeky pleasure in looking over other
       | people's monitor code. :)
        
       | chris_st wrote:
       | Wow, so cool to see the photo with an actual HP-25. I bought one
       | in high school (massive outlay at the time) and loved it. Used it
       | all through college.
        
       | bxparks wrote:
       | One of the PDF files on the GitHub page has some info about the
       | software implementation:
       | 
       | "* The original C version running on Z80 @ 4MHz was really slow!
       | (maybe 25% of HP-25 speed)
       | 
       | * I started to re-write the emulator in Z80 assembly
       | 
       | * would love to finish this someday, but...
       | 
       | * Then I noticed that CMOS Z80 are available rated up to 20MHz
       | 
       | * I ended up running the Z80 at 16MHz, which results in an
       | emulated speed within about 10% of the original HP-25. Not bad"
       | 
       | The other interesting thing is that this uses the 40-pin DIP
       | version of the Z80, which will be discontinued on June 14, 2024:
       | https://news.ycombinator.com/item?id=40083885
        
       | johnea wrote:
       | It's an interesting h/w project, especially if you like nixie
       | tubes.
       | 
       | A more mature s/w emulation of many HP classic calulators is at:
       | 
       | https://nonpareil.brouhaha.com/
       | 
       | I routinely use it's HP-41CV on my desktop. To me the Hp-41
       | represented a breakthrough in programmability.
       | 
       | The RPN user interface of these calulators was also highly
       | superiour entry mode. Sort of the Beta of the Beta VHS shakedown.
       | The superiour solution that lost to a larger marketing budget...
        
         | nextos wrote:
         | I don't think RPN lost. It was not the dominant solution, but
         | it was mainstream. I'd say the situation was more similar to
         | Android vs iOS.
         | 
         | Many engineering students of all disciplines used HPs during
         | the 1980-2000s. At some point, the HP 48 was everywhere in
         | campus.
        
       | kayo_20211030 wrote:
       | This is so cool. These magnificent obsessions are always
       | inspiring; at least to me they are. Just super cool, and why not?
        
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       (page generated 2024-04-25 23:01 UTC)