GO-21 SciRPN

Name: GO-21 SciRPN
Price: 2.99 USD
Rating: 4.9 (12 reviews)
Author: Steve Lidie

Utilities

$2.99

12 Ratings
Age Rating

4+
Years
Category

Utilities
Developer

Steve Lidie
Language

EN
English
Size

15.8
MB

GO-21 SciRPN simulates the venerable HP-21 Pocket Scientific Calculator from 1975. Virtually indistinguishable from the real item in operation, GO-21 is a powerful yet simple retro calculator. • RPN (Reverse Polish Notation) • 10-digit LED calculator display, 10-99 to 10+99 • Four stack registers with roll down • One storage register with arithmetic memory operators • Math, trigonometric, polar/rectangular, logarithmic, power and other miscellaneous functions • One additional window with views of: ◦ stack/storage registers ◦ keystroke log • Copy-from and Paste-to the calculator display • Simple Paper Tape annotations

Ratings & Reviews

4.9

out of 5

12 Ratings

Lean & Mean
09/07/2018
NanoRon
I’ve been using this app for a number of years and have been very satisfied and figured it was time I gave it a review. As an engineer, I loved my HP-21 and was sad when it finally died many moons ago. I searched and searched for a simple reverse Polish calculator app, but could never find a good one. This is a good one. A clean but elegant emulation of a classic design. Highly recommended.
Lean & Mean
09/07/2018
NanoRon

I’ve been using this app for a number of years and have been very satisfied and figured it was time I gave it a review. As an engineer, I loved my HP-21 and was sad when it finally died many moons ago. I searched and searched for a simple reverse Polish calculator app, but could never find a good one. This is a good one. A clean but elegant emulation of a classic design. Highly recommended.
Hate that high visibility setting
01/11/2020
Dhjdhj
To me, the value of this app (and all the other RPN apps that I have) is the authenticity of them. Otherwise, there are a gazillion calculators with different sized displays out there with RPN.Instead of making the X view high visibility, why not enlarge the calculator itself to be full screen (even getting rid of the stack view optionally)Then I’ll go back to 5 stars again which otherwise this app absolutely deserves.

Developer Response
For some thoughts on sizing, see: https://www.bigcatos.com/BigCatOs/go-2x-scirpn/go-21sizehistory.htmlThe App seems to be sized as authentically as possible. The stack view is and always has been optional, simply hide it forever, as described in the documentation.The High Visibility Display setting is optional and disabled by default so you never have to see it, thus the calculator remains in its pristine state. This option has been requested by two groups of users: as an Accessibility assist for those with diminished vision, and folks who use the App outdoors as part of their work.
Hate that high visibility setting
01/11/2020
Dhjdhj

To me, the value of this app (and all the other RPN apps that I have) is the authenticity of them. Otherwise, there are a gazillion calculators with different sized displays out there with RPN.Instead of making the X view high visibility, why not enlarge the calculator itself to be full screen (even getting rid of the stack view optionally)Then I’ll go back to 5 stars again which otherwise this app absolutely deserves.
Developer Response 01/16/2020
For some thoughts on sizing, see: https://www.bigcatos.com/BigCatOs/go-2x-scirpn/go-21sizehistory.htmlThe App seems to be sized as authentically as possible. The stack view is and always has been optional, simply hide it forever, as described in the documentation.The High Visibility Display setting is optional and disabled by default so you never have to see it, thus the calculator remains in its pristine state. This option has been requested by two groups of users: as an Accessibility assist for those with diminished vision, and folks who use the App outdoors as part of their work.
50 years later - Thank you
06/15/2022
Rbollo53
Many thanks for giving me the opportunity to use this RPN calculator. I bought my very first HP 21 C in 1972 when studying at Polytechnic School of Cameroon. 50 years later, I am still very happy and proud using RPN devices and programming Common LISP.
50 years later - Thank you
06/15/2022
Rbollo53

Many thanks for giving me the opportunity to use this RPN calculator. I bought my very first HP 21 C in 1972 when studying at Polytechnic School of Cameroon. 50 years later, I am still very happy and proud using RPN devices and programming Common LISP.
Delightful
11/26/2010
joemeyer
I was 18 when the HP-21 was released but did not buy one until years later when I was in College (I was in the US Army until age 21). This iPhone version is delightful to use and it works very well on my iTouch with the latest OS and indeed fast app switching works well. The display and buttons are easy to see and use. Swiping to see the entire stack is useful. Thanks for writing this app.
Delightful
11/26/2010
joemeyer

I was 18 when the HP-21 was released but did not buy one until years later when I was in College (I was in the US Army until age 21). This iPhone version is delightful to use and it works very well on my iTouch with the latest OS and indeed fast app switching works well. The display and buttons are easy to see and use. Swiping to see the entire stack is useful. Thanks for writing this app.

- Repair broken icon and update documentation. - Update to Apple OS versions 26.5.1.

Version 26.5.1 3d ago

Data Not Collected

The developer does not collect any data from this app.

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Accessibility

Information

Seller: Steve Lidie
Size: 15.8 MB
Category: Utilities
Compatibility: Requires iOS 16.0 or later.

iPhone
Requires iOS 16.0 or later.

iPad
Requires iPadOS 16.0 or later.

Mac
Requires macOS 13.0 or later.

Apple Vision
Requires visionOS 1.0 or later.

Apple TV
Requires tvOS 16.0 or later.
Languages: English
Age Rating: 4+

4+

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