Re: [BLACKBOX] Seasoned Linux.

From: [at]} <József>
Date: Tue, 11 Jan 2011 09:46:26 +0000

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Hi,

What about MINIX 3 ?

"It is irreleveant what language these services are written
in, so long as they obey the protocol. Some of Andrew Tanenbaum's
students are interested in re-writing some of Minix3 OS services (like
device drivers or file systems, currently written in C) in Ocaml and
Cyclone. He is interested in the outcome. Haskell is a good candidate
too. It is quite instructive to compare a device driver in Haskell
with the original C driver -- it terms of length, speed, time to
write, number of bugs, etc. Andrew Tananbaum suggested that the
terminal driver may be the best start, because it is
quite stand-alone, small and its protocol is simple.

        With Minix, we can replace one kernel service of the
full-fledged, working OS with the one written in Haskell -- and
immediately see how it all works. If it doesn't, the rest of OS still
works and so we can unload the faulty service and load another
implementation. Minix3 does indeed offer an easy road to the OS kernel
for a language other than C."

http://www.haskell.org/pipermail/haskell/2006-June.txt

"This new OS is extremely small, with the part that runs in kernel
mode under 6000 lines of executable code. "

http://www.minix3.org/

Regards,
Jozsef


On 11 January 2011 04:17, Wojtek Skulski <skulski{([at]})nowhere.xy
>
> On Mon, 10 Jan 2011, Rex Couture wrote:
>
>> In spite of the very useful nature of a lot of modern software, I'm sure we all agree that the overall quality is somewhat disappointing.
>
> Very early in my project cycle I made an evaluation of "useful versus disappointing". I chose the "useful" despite knowing the "disappointing" component from my earlier encounters with Linux as a home-grown administrator. I sort of knew that getting deeper will not make my task any easier. I decided in favor of Linux, partly because an alternative is not in sight. For example, I could have adopted BlueBottle if it was running on the Blackfin processor. But it is not.
>
> I am now reading a few books on Linux kernel: one on Embedded Linux, another one on Linux Device Drivers, and yet another one on TCP/IP in Embedded Linux. More books are in the queue. I can rank these three books on a scale from "messy" to "unacceptable". None of the three reads well, even though Linux Device Drivers is the least terrible from the three. I am wondering, why these books give me headaches.
>
> I am thinking that the books reflect the basic design feature that Linux kernel has no hierarchical structure. It does have some structure, which is rather arbitrarily declared in the form of the directory tree and which files is where, and how it is named. Being mandated by humans, the rules are also freely trespassed by humans. The books make it abundantly clear that in fact there are no rules which would not have been trespassed.
>
> Lack of hierarchical structure makes the books "flat". It reads somewhat like this: "this is here, and that is there, and by the way something else is also there". I am finding it hard to memorize "this is here and that is there". The big picture is not emerging (yet) because I suspect there is no big picture in the Linux kernel. There are features. Some of them extremely useful. But hard to remember.
>
> The good news is that linux kernel is self-contained. There are no libraries in the kernel. (How many of you knew that?) The number of external references is therefore small. (Most likely there are none.) Linux kernel directory tree just sucks everything in. Whatever feature the developers have found useful, it is somewhere in the file hierarchy. It is impossible to guess, where it is possibly hiding. That's why the books are so thick.
>
> I should also say that Linux kernel contains many constructs which we in this group have hardly encountered: semaphores, spinlocks, work queues, tasklets, interrupt service routines, and perhaps a few more. We live in a safe world of the single-process multitasking. The Linux kernel is a dangerous place littered with critical sections. It is a bit unfair to compare the two systems without admitting the difference.
>
> My next task is to develop the interrupt service for my FPGA. The more I am looking into it, the more it looks like an egg to me. I am not exactly sure yet in which place I will dig the hole to get me inside the egg's shell. That's why I am reading these books.
>
> I can already appreciate that reading the fourth book "Inside Linux kernel" cannot be avoided, even though I hoped to never look inside.
>
> Wojtek
>
>
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Received on Tue Jan 11 2011 - 10:46:26 UTC