KnightOS is a third-party Operating System for Texas Instruments z80 calculators. It offers many features over the stock OS, including multitasking and a tree-based filesystem, delivered in a Unix-like environment. KnightOS is written entirely in z80 assembly, with a purpose-built toolchain. Additionally, the KnightOS kernel is standalone, and you can use it as the basis for your own powerful operating systems.<p>You can download the latest (experimental) version here: http://www.knightos.org/download/
I'm the author of this software, with the help of some open-source contributors. Feel free to send questions my way.<p>Even people who don't know assembly can help, if you're interested. We need assembly, C, Python, and web programmers. Let me know if you're interested in helping out.
Another project worth mentioning is [GlassOS](<a href="http://www.cemetech.net/forum/viewtopic.php?t=5686&highlight=glassos" rel="nofollow">http://www.cemetech.net/forum/viewtopic.php?t=5686&highlight...</a>) which is an operating system for the TI-8x series calculators written in C and compiled with sdcc. It doesn't offer multitasking (or at least not background tasks, suspending and resuming might be planned, I don't know). It also supports some fairly gimmicky things like system-wide grayscale settings. It also hasn't seen any development for several months, which makes me sad.<p>KnightOS seems to be more focused on just providing a sane environment for user programs instead of TI's stock OS which is calculator-first and user programs are second class citizens.<p>I'm not sure how practical preemptive scheduling with background tasks is for these devices, they really are resource constrained. I'm sure it works fine with one background process, especially if it clocks up the cpu for that, but I don't see it scaling much beyond that. I'll have to try it out some time.<p>I'd be interested to see if a compatibility layer for programs written in C could be set up. SDCC's binaries tend to be reasonably performant, but significantly larger than their assembly equivalent. With 31k available to programs however, C could work for a lot of applications. I might hack on that sometime.
If you want to see a never ending well of software for TI calculators check out <a href="http://www.ticalc.org/" rel="nofollow">http://www.ticalc.org/</a>
Needs the most important feature that prints out the "Memory cleared..." text as the original TI-OS would to fool the teachers and still have your crib notes!
Wow, this brings me back to the early 2000s and MirageOS, which wasn't actually an OS but a glorified shell: <a href="http://www.detachedsolutions.com/mirageos/" rel="nofollow">http://www.detachedsolutions.com/mirageos/</a><p>This is a complete replacement though, right? IIRC, the firmware updates had to be signed, how did you get around that?
Other than tinkering, what's the point of that project?<p>AFAIK you buy those things because you want TI's math software, not because you need some hardware to run your software on it. After all, these are <i>a bit</i> pricey if just look at the hardware, right?
Wow. Good job!
Unfortunately I lost my TI-84, I'm tempted to try KnightOS on an emulator on an android tablet, running in an emulator on my laptop.