GO-21 SciRPN

GO-21 SciRPN

By Stephen Lidie

  • Category: Utilities
  • Release Date: 2009-08-28
  • Current Version: 6.6.3
  • Adult Rating: 4+
  • File Size: 10.60 MB
  • Developer: Stephen Lidie
  • Compatibility: Requires iOS 12.0 or later.
Score: 4.91667
4.91667
From 12 Ratings
$2.99 On itunes

Description

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

Screenshots

Reviews

  • 50 years later - Thank you

    5
    By 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.

  • Hate that high visibility setting

    4
    By 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.

  • Lean & Mean

    5
    By 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.

  • My thoughts on the HP 21 app

    5
    By lbartosh
    I have an hp 21 that we purchased new and I've always loved it, not only for the RPN feature but for the simplicity. This is such a nice app for anyone familiar with the HP line plus it shows the stack. Highly recommend.

  • Return with us now to the days of yesteryear

    5
    By Noneblank Nickname
    I bought an HP-21 during my third semester of college in 1976. At that time they were still teaching students how to use a slide rule. The app is a very good reproduction of the HP-21's look and functions/functionality. I has the functions I want and doesn't have a lot of functions that I don't use. It has a useful Help file.

  • Nice

    5
    By Oscore
    Loved my 21; spent many hours with it in college. Doesn't charge anymore, but I still keep it around. This is an excellent reproduction. And then some.

  • Great Improvement on a Classic Calculator

    5
    By zcave
    I used an HP-21 calculator in college back in the late 70's and early 80's. The rectangular-to-polar and polar-to-rectangular conversions were a lifesaver for an engineering student back then. This app is a great update to the original. The built-in help is excellent too. The ability to "commify" numbers is my favorite added feature. The developer is also very responsive.

  • Delightful

    5
    By 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.

  • Great implimentation!

    5
    By Bob RJB
    A Classic! Just like my old HP-21 -- even to the realistic LED display. I have at least a dozen RPN calculators (both real and as iPhone Apps). Many are much more complex with lots of advanced features. But, if you are a RPN user, this HP-21 App is just perfect for going to for quick straight forward calculations. It has become my most used calculator.

  • Great RPN Calculator

    5
    By critter2
    Perfect implementation. It is fabulous to have access to the RPN calculator I used most of my career (and still have and use) and not have to learn another model!

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