Dev tools · alternatives · 2026
24 alternatives to KnightOS
An open-source OS for calculators
Below are 24 products that do a similar job, ranked by how close each is in meaning and then by launch-day votes. KnightOS launched in 2016; newer entries below may have overtaken it.
- 1KA
2016 · knightos.org · its alternatives →
- 2IB
You know that old TI calculator you used in high school, then put in a box and forgot about? Have you ever wished you had an operating system for your calculator with preemptive multitasking, dynamic memory management, a tree filesystem conforming to the FHS, and all the comforts of Unix? Well, good news: that's totally a thing that exists. I've been working on my kernel for about three and a half years now and I'm looking for new contributors to help out. It's written entirely in z80 assembly, and it's both challenging and fun to work on. There's an IRC channel for contributors or people…
2014 · its alternatives →
- 3
- 4
Orchestra▲75Open source system for coordinating experts and machines
2015 · orchestra.b12.io · its alternatives →
- 5
- 6
The Intelligent Calculator & Unit Converter
2015 · apps.apple.com · its alternatives →
- 7
The core question: how did HP's scientific calculators actually work at the gate level? That rabbit hole led to building one from scratch. The architectural decision everything else follows from: a decimal calculator should store numbers as BCD — one decimal digit per 4-bit nibble. A standard byte-oriented CPU (Z80, 6502) fights that layout constantly. So I designed a small custom CPU in Verilog where 4 bits is the natural data width and memory is nibble addressable. What the project covers: - Custom CPU: Harvard architecture, 12-bit ISA, 8-state execution FSM, hardware stack guard with a…
May 2026 · github.com · its alternatives →
- 8
- 9
- 10
- 11
Calcbot▲111The intelligent calculator and unit converter by Tapbots
2014 · tapbots.com · its alternatives →
- 12
Tydlig▲57A new kind of Calculator for iPhone & iPad
2013 · store.steampowered.com · its alternatives →
- 13
Visually Impressive Highly functional All-in-one!
2016 · play.google.com · its alternatives →
- 14
Numby▲83A natural language calculator for your terminal and macOS
Nov 2025 · numby.vivy.app · its alternatives →
- 15
The modern calculator for macOS/iOS
2020 · euclid.pr1mer.tech · its alternatives →
- 16
Awesome gesture-based calculator. Beautifully designed.
2014 · rechner-app.com · its alternatives →
- 17
- 18
- 19
The open source thinking tool for problem solvers
2016 · kickstarter.com · its alternatives →
- 20AS
2018 · bwasti.com · its alternatives →
- 21
TrueOS▲11A powerful free and open source software to get the job done
2016 · truenas.com · its alternatives →
- 22
Calzy 3▲8The Smart Calculator: beautifully new + much² better
2018 · waplestuff.com · its alternatives →
- 23
Rizon▲25A beautiful Golden Hour calculator for iOS
2015 · reiseversicherung.de.com · its alternatives →
- 24
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Ranked by how close each launch is in meaning, then by votes. Prices were read from each product’s own site when checked and can change. Refine with your own description →