Precision of DM42 vs. DM41X

Discussion about the new DM41X calculator
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NoisyBoy
Posts: 12
Joined: Thu Jun 25, 2020 7:49 am

Precision of DM42 vs. DM41X

Post by NoisyBoy »

I did some searches on the forum but I could not find any reference to the accuracy of DM42 vs. DM41X. I am aware of the precision in the DM42, and the SHOW function allows me to see the glory of all the digits. But I have not been able to come across anything similar in the DM41X, can anyone shed some light on this topic?
ecsfang
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Location: Lund/Sweden

Re: Precision of DM42 vs. DM41X

Post by ecsfang »

Hi!

The DM41X is (almost ;)) a 100% replica of the real HP-41-series (regarding firmware - reusing the code from the original machine).
For internal calculations the 41-series uses 13 mantissa digits, and on the display it is rounded to a 10-digit mantissa, both with a 2-digit exponent of 10.

The firmware of the DM42 is rewritten from scratch and have been extended to be "the most precise calculator on the worldwide market - second to none".

So, it is unfair to compare these two calculators (when it comes to speed and precision) even if they share the same hardware: DM41X runs an emulator that execute the original 41 ROM code (with the possibility to use almost all old software modules, both FOCAL and MCode versions), while DM42 runs newly written native firmware that mimics the HP-42S (so it looks and feels like the original - but completely new code).

Hope that helps ... :)

Regards,
Thomas
[35/45/65/67/25/29C/31E/33E/41C|CV|CX/71B/10C/11C/15C/16C/32SII/42S/28S/48GX/49G/35S/DM41X(#00456)]
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Thomas Okken
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Re: Precision of DM42 vs. DM41X

Post by Thomas Okken »

ecsfang wrote:
Tue Oct 20, 2020 8:02 am
So, it is unfair to compare these two calculators
Sure it's fair! Emulation and simulation are different means to mostly similar ends. They each have their pros and cons. Nothing wrong with pointing that out.

(For me, the biggest pro of the simulation approach was that I knew how to do it. Writing or porting a Saturn emulator, i.e. a CPU I'm not at all familiar with, and then debugging it by running the 42S ROM on it, which I'm also unfamiliar with... that seemed like a doomed approach, and that's not even considering the fact that the 42S ROM is not legally available for redistribution. The cons were that simulation of a complex calculator is a lot of work and you end up having to fix a lot of bugs. Speed and accuracy weren't even on my radar at the time, other than wanting to make sure that at least Free42 wasn't slower than a real HP-42S while running on a Palm m100. :mrgreen:)
ecsfang
Posts: 26
Joined: Sun Jan 26, 2020 5:21 pm
Location: Lund/Sweden

Re: Precision of DM42 vs. DM41X

Post by ecsfang »

Hi Thomas!

That's true ... I just wanted to point out the difference, and why the DM41X can't compete with DM42 regarding precision ;)
And just as you say, both are marvellous machines in their own ways!

Cheers,
Thomas
[35/45/65/67/25/29C/31E/33E/41C|CV|CX/71B/10C/11C/15C/16C/32SII/42S/28S/48GX/49G/35S/DM41X(#00456)]
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NoisyBoy
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Joined: Thu Jun 25, 2020 7:49 am

Re: Precision of DM42 vs. DM41X

Post by NoisyBoy »

Hi Thomas and Thomas,

Thank you so much for the excellent explanation, that makes perfect sense. I love both machines, what a great combo, one high fidelity, the other high optimization/precision. They make great addition to my HP collection, I am just thankful for SwissMicros and all the developers/beta-testers for making it a reality.

Sincerely,

Gordon
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