08:43 <Guest88> Hello

08:44 <Guest88> ?

08:44 <Guest88> Anybody?

08:48 <jn> Guest88: hi welcome. please ask the question that brings you here, instead of "anybody?"

08:55 <Guest88> What language is the arm kernel compiled in?

09:04 <Xogium> Guest88: what do you mean what language ?

09:04 <Xogium> its compiled into raw binary your machine understands

09:05 <Xogium> like pretty much any other program

09:05 <Guest88> I was reading up on how kernels are made. I presume they are compiled in a language like basic, cobol, or c right?

09:05 <Xogium> oh yes, in that sense

09:06 <Xogium> the linux kernel is written in a few languages, C for the most part, but there's a little bit of c++

09:06 <Xogium> things like that

09:07 <jn> it *written* in C (by human programmers)

09:08 <Xogium> not to say you can't write a kernel in other language, but the kernel is ancient, so it started with C

09:08 <Guest88> But what exactly is a kernel? Is code that moves memory around, and calling programs back and forth?

09:08 <Xogium> ;p

09:08 <jn> it is *compiled* from C over ARM assembly language to ARM machine code

09:08 <Xogium> hello, jn :)

09:08 <jn> hi Xogium :)

09:09 <Xogium> oh boy the what is a kernel question. That one is tricky

09:09 <Xogium> so many definitions depending on what kind of kernel you mean, like micro kernel

09:09 <jn> Guest88: feels like "what is an elephant?" i could list a few aspects, but no ultimate definition

09:10 <Xogium> jn: at the risk of sparking a mini debate, just for fun and because I'm curious, would you have prefered linux be a micro kernel or a monolithic one ?

09:10 <jn> Guest88: the kernel runs in a higher privilege mode ("ring" in x86 terminology) than application programs

09:11 <jn> Guest88: the kernel manages page tables and provides the virtual file system API (read, write, open, close, etc.)

09:11 <Guest88> Yeah, can't seem to get a clear description of what it is. I suppose my long term objective is to find what I have to do to get software and hardware integration. At the computer level rather than the driver level.

09:11 <Xogium> manages hardware too

09:11 <jn> Guest88: the kernel schedules processes

09:12 <jn> Guest88: what do you mean by "software and hardware integration"? when would you consider it achieved?

09:12 <Guest88> Schedule processes.

09:12 <Xogium> the other day I had to explain to someone who was very curious that no, you can't have a shell and OS and all of that running if you don't have a kernel

09:12 <jn> oh, btw, when we talk about "the kernel" here, we mostly mean a specific kernel, the Linux kernel

09:13 <Xogium> but that was a fun talk

09:13 <jn> Guest88: processes are scheduled all the time, you don't need to think about it, just like you don't need to think about the blood that's pumped through your body by your heart

09:15 <jn> Xogium: i slightly disagree, you can very well have *a* shell, just not a fully featured unixiod shell, without a scheduler

09:15 <Guest88> Prosthetic arm for example. Input and output sensors at different pressures. How would a kernel handle the on and off sequence, hardware input, output. And other minutia of processes?

09:16 <jn> to avoid confusion right away, please say prothetic leg

09:16 <Xogium> there's only one thing I don't like much in linux, the way it can kill misbehaving kernel modules and simultaneously shoot itself in the foot doing so. Then again I suppose you just shouldn't use misbehaving drivers...

09:16 <jn> confusion between arm (body part) and ARM (CPU architecture)

09:16 <Guest88> Lmao I see...

09:16 <Xogium> rofl nice one

09:17 <Xogium> awesome confusion

09:17 <Guest88> It was coll that you caught that.

09:18 <Guest88> /Cool

09:18 <Xogium> when I saw the message about replacement limbs I was like, huh ? And then it clicked hehehehe

09:18 <Xogium> but jn was faster

09:19 <Xogium> I blame it on my not yet fully awake brain

09:20 <jn> anyway, i haven't worked with the internal details of a prosthetic leg that works with a bunch of sensors, you'd have a control loop in the main application. it would poll the sensors, calculate some things, and perhaps drive the actuators depending on the calculated values

09:20 <jn> this loop would probably run a fixed rate (for example, 100 iterations per second)

09:20 <Guest88> Lol, I'm trying to sleep but I been trying to wrap my head around this kernel concept.

09:21 <jn> when one iteration is done, the application would tell the kernel: please wake me up in 3.2 milliseconds, or whatever

09:22 <jn> a prosthetic leg is so far removed from a general-purpose computer that it could do very well without many of the features that are present in the linux kernel

09:22 <jn> you don't need a filesystem, a network stack, or even necessarily multiple processes there

09:22 <Xogium> indeed

09:22 <Xogium> rtos ? Maybe

09:23 <Xogium> or even bare metal

09:23 <jn> yeah, it seems like a classic case for a lightweight real-time operating system (RTOS)

09:23 <Xogium> aka no kernel and just running a little program that controls the whole thing

09:23 <jn> (which arguably also has a kernel, but a smaller one)

09:24 <Guest88> RTOS like arduinos?

09:24 <Xogium> hmm do arduino have rtos ? Good question. I think those run only tiny programs

09:24 <jn> Guest88: when you run an application on an arduino, it's usually the bare-metal case as Xogium described

09:24 <jn> without an RTOS

09:24 <Xogium> they would be too tiny to have a full OS, however small in them

09:25 <jn> you *could* put a tiny OS on there, but it adds complexity and arduinos are designed for beginners

09:25 <Xogium> yep

09:25 <Xogium> there's that too

09:26 <Xogium> jn: speaking of rtos and such, I'm trying to make an hardware synth and porting espeak-ng to stm32 :) this would talk over serial to speakup

09:26 <Guest88> So you're talking more about RPI's then. Which is what I'm trying to work with. But not exactly on prosthetics, more of a control center for a few turbines and a phletora of sensors that would control other equipment.

09:27 <jn> Xogium: fun project! does espeak have a voice that sounds a little better, by now?

09:27 <Xogium> jn: depends... Its got lots of variants to choose from, but its never going to sound human, due to how it is built

09:28 <jn> Guest88: what i mentioned about a control loop applies in general

09:29 <jn> Xogium: ah, i guess you have to get used to espeak's idiosyncracies then :)

09:29 <Xogium> but the thing is I'm sometimes having issues where my linux audio just goes on vacation so to speak, and I get stuck. Sometimes its a kernel update, sometimes its a pulseaudio update, and sometimes it can be alsa-lib. I need to get something I can count on to be still working after this has gone to hell

09:29 <jn> makes sense

09:30 <Xogium> so that sparked the idea of making a modern hardware tts and that snowballed from there

09:30 <Guest88> Got ya.

09:30 <Guest88> Thanks.

09:30 <Xogium> Guest88: no prob :D

09:31 <Xogium> so I discovered there is in fact, next to no usable tts on microcontrollers

09:32 <Xogium> and it seems like noone ever attempted to port espeak, which should be easily doable. Considering it is a direct decendent of a program that was written long ago in the 80's

09:32 <Xogium> but the task is a lot more complex than we thought it would be

09:33 <Xogium> like the fact that phoneme generation is done on the fly from some files that take ~1 MB of ram

09:33 <jn> Guest88: one term to perhaps research while designing your turbine control thing: SCADA

09:33 <Guest88> SCADA? Heard mention of it. But I must Google it.

09:38 <Xogium> jn: also trying to render speakup/espeakup software bridge multi-user capable

09:40 <Xogium> currently it can only be made to work with a single user, which is root by default, or you could have some acl added by systemd for your user kind of thing, but that still doesn't give multi-user support. So idea is to have a sort of espeakup launcher daemon that will control every user instance of espeakup and handle the talk between the espeakups and speakup. That way, this runs as root but doesn't

09:40 <Xogium> prevent you from having your own instance of espeakup for your user

09:42 <Xogium> that would also solve the whole mess with having to run espeakup as root for it to access the kernel module, which means your user can't hear it unless you hack away at pulseaudio