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  • Released
  • Updated
  • January 6, 2013
  • September 24, 2026

Features

Jupiter ACE screenshot #1 for iPhone
Jupiter ACE screenshot #2 for iPhone
Jupiter ACE screenshot #3 for iPhone
iphone
ipad
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About

Explore the history of computing by learning the Forth programming language on a simulated 1982 home computer. This educational tool provides an authentic experience for aspiring programmers interested in retro technology.

✓Forth programming language simulation
✓1982 home computer emulation
✓Educational retro computing experience
✓Freely available source code
✓iPad compatible
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What's New in Jupiter ACE

2.0

September 24, 2026

iACE has been rebuilt from the ground up, and now runs on iPhones as well as iPad: • sound on every device • .TAP tape import and export, and a tape browser • volume control • sharper graphics on every iPad size Your saved tapes and settings from iACE 1.x are kept.

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User reviews

Super ACE Emulator!

Der Jupiter ACE Emulator ist echt super gemacht, oben mit dem Bildschirm, in der Mitte mit dem Gehäuse und der Tastatur und unten mit dem Handbuch! So kann man die Beispiele im Buch echt gut nachvollziehen!

Einziger Kritikpunkt ist die Tastaturabfrage - manchmal wird einen Tastendruck ungewollt wiederholt, was vor allem beim Löschen störend ist, wenn man z.B. nur ein Zeichen löschen will und dann gleich mehrere gelöscht werden.

Schön wären auch Cursor (Pfeil-) Tasten die man direkt ohne Shift erreichen könnte.
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iPad Pro keyboard repeats too fast

App looks good (got it practice Forth while I refurb a real one), but the too rapid repeat makes typing anything so annoying I’ve given up.

A good forth for the iPad

It is good that there is a good forth for the iPad.

A little better with each revision

9 Apr 2018

I could not continue my chain of reviews ... it always happens with updates. Edward Patel is back and working through some of the “annoying” issues with his Jupiter Ace emulator on iOS, in particular with the app on iPad Pro 12.9 in. devices.

Results now show up on scrolled down screen. Manipulation of screen and keyboard still remains very awkward. It would be better to just have a static screen of the entire surface of the Jupiter Ace and to use the traditional gear type icon for settings and question mark icon for the help section (which is really good).

The second thing which either needs to be dumped altogether or made a user option to disable is the key repeat. It is just too “sensitive” and becomes very annoying very quickly.

There were obvious user interface annoyances on the Jupiter Ace; but, the app should attempt to clean up those problems. While I laud the effort to bring back a piece of history and nostalgia, I echo what some user’s have said, there needs to be a good Forth interpreter written for iOS that adheres to the language standard and does not emulate past devices.

I still want to love this app and will continue to monitor and test improvements though ... so keep the improvements coming.
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Response from developer

Sorry you had some problems. It was already 3 years old when you tested it. Try now, I just updated it this weekend. Have fun! Cheers. Also, looks like I should mention how to drag the screen down. Please see this https://youtu.be/-2LUG2X1nSg where I show how it works from a cold install. Cheers.

No native Forth so far.

That's the only Forth for iOS.

FAQ

What is Jupiter ACE?

Jupiter ACE is an emulator that allows you to learn the Forth programming language on a simulated 1982 home computer. It's designed for educational purposes, offering a glimpse into early computing.

What programming language does Jupiter ACE teach?

Jupiter ACE specifically teaches the Forth programming language, which was the built-in language for the original Jupiter ACE home computer in 1982. This is distinct from the more common BASIC language used by other computers of that era.

Is Jupiter ACE available on Android or other devices?

Currently, Jupiter ACE is only supported on iPads. The application's compatibility is limited to Apple's tablet devices.

How often is Jupiter ACE updated?

The latest version of Jupiter ACE is 1.2, which was last updated on March 26, 2018. This indicates the app has not received updates in several years.

What is the user rating for Jupiter ACE?

Jupiter ACE has a rating of 4.0 stars based on 8 user ratings. This suggests a generally positive reception from its user base.

Is Jupiter ACE suitable for young children?

Jupiter ACE has an age rating of 4+, making it suitable for children. However, the complexity of learning a programming language may be more appropriate for older children and adults.

Can I use Jupiter ACE offline?

The provided information does not specify whether Jupiter ACE can be used offline. However, as an emulator for a programming language, it is likely designed to function without an active internet connection once installed.

Does Jupiter ACE have ads?

No, Jupiter ACE does not contain advertisements. The application is free to download and use without any ad interruptions.