I've spent 4 years making a free operating system for calculators (in assembly). AMA!

Um... Why?

I first got into programming with TI calculators, when I had one in high school. I want to build an entirely open system that students were encouraged to hack on and toy with, which would hopefully get more people interested in coding early on. KnightOS is really interesting from a technical perspective, and it introduces programmers to concepts that I think are important to learn.

You're the Richard Stallman of Texas Instruments.

A better analogy might be Linus Torvalds.

Any other projects you have been working on? Or ones you would like to start?

Thanks for asking! I work on a ton of open-source projects, here are a few:

• https://mediacru.sh
• https://kerbalstuff.com
• A Reddit API wrapper
• An open implementation of Minecraft

I also contribute code to projects like RES and ImageMagick, but KnightOS is definitely my favorite project.

Was there a reason you decided to stick with assembly for the whole is instead of bootstrapping to c like most other current os'es?

TI calculators run on z80s. These processors have C compilers, but they don't work very well - they produce rather bloated code, and often slow code. It's unfortunately unacceptable for a kernel on such limited systems to be written in C.

Wouldn't it have been easier to rewrite the c compiler than write an entire os in assembly?

Probably not. The compilers aren't poorly written, it's just that we're really resource starved here. Hand-optimized assembly is the way to go.

What do you do to pay the bills?

Write software as a consultant.

How long did it take you to learn how to program in assembly code? I'm working on java right now and my college offers C training, but I'm blowin through java.

I'd take that C course if I were you. It took me only a few months to learn, but it took me a few years to get good at it.

I was gonna work in learning both, and python and ruby while I was at it. Too much?

You could make it work. I believe in you.

Is there any way to go back to the calculator os after you've installed this?

Yep, instructions are on the download page.

The TI-82 was pretty easy to pick up and start programming with a minimum of study. Will this be as easy for end-users to code on?

Easier. It's built like a Unix system and we're working on something resembling Python. It's super hackable and users are encouraged to hack it :)

Is that the driving motivation? Giving something back for the next generation of coders?

edit: I mean is the programming environment your primary focus?

That, and to make something that's fucking awesome.

I'm picking up a TI84 in the morning and taking the rest of the day off.

Great :)

Honestly, this is awesome. It's great to see a project being followed through - so my question is, what gave you motivation to continue developing this software?

The rest of the people involved keep at it and inspire me to do so, too :)

Awesome, how big is your team (or people that are involved?)

https://github.com/KnightOS/KnightOS/blob/master/THANKS

So uh, what sort of features does that is have over the stock OS in terms of the average user? And does the calculator still have all the functions that the stock OS has?

It has a proper filesystem, and multitasking. The last one means that you can run several programs at once, and switch between them (you could have three graph screens and a game playing at once, for example). The filesystem means that you (will be able to) plug it into your computer and treat it like a flash drive.

What's your educational background?

Finished high school, skipped higher education.

How old are you and why did you decide to skip higher education?

I'm 21 and I skipped it because i don't consider it worthwhile for my own needs.

Will the TI Nspire series be supported?

No, but we wrote an emulator that it should be possible to get running on the Nspire.

has Texas Instruments ever contacted you?

Nope.

would you like them to? your OS sounds like a real improvement over the existing one, and being open source I can see a future where TI starts sponsoring your team's effort for their own benefit, and every engineering student benefit.

I think so, yes, but conditionally. TI hasn't always been nice to its hacking community. I would insist that KnightOS remains free and open source and that I could continue leading the project if I were to accept any kind of sponsorship from TI. We could use it, though, this project is huge and complex and it's taken 4 years so far just because I can't spend all of my time on it (and it demands a ton of time).

Not sure if you remember me; nonetheless, what resources did you use in order to make the operating system? Also, I've always wanted to help out with KnightOS but I unfortunately fell victim to the nspire family. Any way for me to contribute (code wise)?

I do remember you! And there's good news - there's work to be done for KnightOS in assembly, C, Python, JavaScript, and LaTeX (not just assembly!). You can join us on #knightos on irc.freenode.net to chat with devs and find something interesting to work on. There's even stuff to do for the Nspire ;)

Can we see these operating systems in action ?

There's an emulator on the home page that's running the latest version. It's a bit buggy, though!

Is the OS in color for the TI84+CSE and if not is it planned to be?

Somewhat. It has a legacy mode for compatability that simulates the monochrome screen, but programmers are able to use color mode instead.

How hard would it be to get it working for a TI-86? It has the same CPU as the 83+, and more RAM, but a non-upgradeable 256k ROM, which I think is probably a barrier here.

Impossible. You hit the nail right on the head.

What are your favorite chrome extensions and websites other than reddit?

I use Firefox and I also like Hacker News.

Hey! This is an awesome project. I would love to work on something like this. I'm still in school but systems and low level projects like this really interesting. A few questions! Did you find the instruction set for the z80 limiting in any way and what was your debugging process like? Id imagine there arent a lot of helpful tools out there for a project like this. Thanks!

The z80 has a generous instruction set which isn't too limiting. It's got support for a lot of nice things that are less common on 8 bit CPUs, like good bit manipulation.

For debugging I've mostly used emulators. On the 84+ CSE, however, there were no emulators when I got started. I couldn't even get the screen to turn on at first and I ended up wiring an LED into the link port and making it blink to communicate debugging information to the outside world.

Hi there, is it possible to create bitcoin key pairs (public and private) with this OS running on the calculator? And is it also possible to create QR codes that represent the bitcoin key pairs?

Is it possible? Yes. Is it feasible? Not really.

Hrmm, I dont think you understand how great this would be. This would make a pretty sweet offline bitcoin QR code, key generator. But it sounds like it might be quite a hassle?

The system is too slow to do cryptography at any sort of reasonable speed. We can verify signatures fairly quickly, but not much else. On top of that, you'd have to write your crypto code in assembly.

Hello, Sircmpwn,

I used to do a lot of programming on the ti-84 back when I was in high school however I did mine internally on the programming function built into the calculator itself. I got pretty deep into it, when I switched to the 89, and was the only one at my school capable of writing codes for various functional computations. I got as far as developing my own programs for different things subjects (calculus and physics) where each had a custom UI that would provide a set of available functions and each one could be selected for which unit you're solving for (teachers loathed me but some asked for my help to write code for approved test-helper formulas).

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Basically my question is this: How does coding on the computer directly for the TI differ from coding within the TI itself and how can I get into coding on the computer

Added question if you have the time: How does the language differ from the different versions of TI, 87, 89, 93, and is it difficult to learn others if I started on the 89?

Thanks !

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Edit: editing

Coding "on the metal" is a lot different. You're probably referring to TI-Basic, which you can author directly on the calculator. TI-Basic is a simple language with simple constraints. On the other hand, you write code that runs on the metal in assembly, which is a simple language with much tighter constraints. You can pick it up, though. I can't really offer suggestions for programming on the stock OS, but I can offer you some resources for programming on KnightOS.

As for the differences between models: we use the same codebase on all of the models we support. They all use the same z80 CPU and have only minor differences to consider. However, not all TI models use the z80 or have similar enough designs. We don't support the TI-89, for example, which uses a totally different technical design.

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You probably won't find it practical unless you have a specific constraint that demands it (like I do). Learning it, however, can be very valuable to come to a deeper understanding with how your computer works. I suggest you do so.

Why is the calculator so expensive

Also how should I start coding assembly (I know there's no point), I'm on a debian variant.

Because TI has a monopoly.

You can start writing assembly for calculators by installing our WIP SDK and genkfs, then heading over to our documentation.

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Answered

Better you than me, friend.

Eh, it's not so bad once you get used to it. We wrote the toolchain in C, though (I wrote my own assembler and a bunch of other tools that help compile the OS).

You can read the code here if you like.

What, may I ask, does your OS do for a calculator? I have a TI 84 plus and it does pretty much everything I need it to, except surf the web but it doesn't have the memory for that and has a black and white screen and it would be terribly awkward to view websites. So please explain why I would need a different OS on my calculator.

The features are described on the home page: http://www.knightos.org, along with an emulator so you can see for yourself. To quote the download page, though: "KnightOS isn't done, and you may be underwhelmed."

Thanks for posting this, actually, it's very motivating, have to ask: 1-How & where did you start learning assembly? and good resources? 2-How did you learn writing OSes? also any good resources you recommend? 3-Is writing an OS for calculator is different than writing an OS for PCs?

1. http://tutorials.eeems.ca/ASMin28Days/lesson/toc.html, years ago
2. I just wrote one and learned as I went along
3. I haven't written an OS for PCs so I can't say for sure.

1) What do you have planned for future development?

2) Can it handle Doom?

1. A bunch of technical stuff - a virtual filesystem, USB host support, and if I'm lucky a TCP/IP stack. For students, I'm hoping to have complete feature parity with the stock OS in the next couple of years, but that's not really my line of work - I'm a kernel guy. I'm lucky to have a bunch of people helping with the userspace that can help realize that goal.
2. Not yet, but it will ;)

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No? I don't see how it could.