
I’m writing my own OS - maidenhead
http://gusc.lv/2012/11/im-writing-my-own-os/
======
ChuckMcM
Sigh, folks give the guy a break.

Sure he doesn't know what he doesn't know, but he has decided to fix that.
Which, if you know your history, is not a whole lot different than Linus back
when he was calling out Minix for being crap.

The challenge here is that the barrier to speaking on the interwebs is quite
low so you can make a fool of yourself if you're not careful.

Jean Labrosse, who wrote uC/OS (which everyone called mucos), in his original
thesis statement made many of these exact same arguments. And like your author
he made some choices that he felt were reasonable, only to learn through
experience that perhaps they weren't a well thought out as he had hoped.

I am a _huge_ fan of people just saying "How hard can it be?" and jumping in.
Enjoy the ride, they can surprise you if you under estimate them.

So assuming this person notes that they are getting a ton of traffic from HN,
and comes here to investigate, my three suggested books are :

Operating System Concepts [1], Operating System Implementation [2], and The
Design of UNIX [3]. Preferably in that order. Any decent college library
should have all three in the stacks.

[1] www.amazon.com/Operating-System-Concepts-Seventh-Edition/dp/0471694665/

[2] www.amazon.com/Operating-Systems-Design-Implementation-3rd/dp/0131429388/

[3] www.amazon.com/Design-Operating-System-Prentice-Hall-
Software/dp/0132017997/

~~~
bcantrill
Agreed; the criticism here is way too harsh. In particular, I think it's
somewhat amusing that people are giving him grief for wanting to "jump to C as
soon as possible." Any rational kernel developer wants to jump to C as soon as
possible -- and wants as much of the system to be in C as possible. (Indeed,
this is the ethos that drove Unix -- and separated it from the horrifically
unportable systems that predated it.[1])

Further, there are some good ideas here -- in particular, jumping directly to
long mode allows one to avoid much of the replaying of the history of the PC
that one is historically required to do to boot an x86. Most civilians (and I
dare say, most of the negative commenters here) have NFI how ugly this process
is and how much of a drag it is on future development. With the decline of the
PC, it's reasonable to believe that a future is coming in which x86 becomes
primarily a server-side microprocessor -- and begins to shed much of the
baggage from the misadventures of the 1980s and 1990s.

All that said: there is a certain arrogance of youth here, and one hopes that
when reality has sandblasted it away, the resulting humility will find its way
to a formal computer science education and ultimately into professional
software engineering; our discipline needs more people who have dared to write
an OS from scratch, not fewer.

[1] <http://cm.bell-labs.com/who/dmr/cacm.html>

~~~
javajosh
Very well said, particularly _our discipline needs more people who have dared
to write an OS from scratch, not fewer_. Truth is that I've thought about
doing what the OP is talking about, but quailed at the complexity of it.

That said, I'd be interested in making an OS that gets to _JavaScript_ as fast
as possible. Yes the system would be a dog, but sure would be fun to build.

~~~
tptacek
At least when it comes to systems programming, but probably across our whole
field, most seeming impossibility has more to do with fear than real
difficulty. I've spent a lot of time clumsily trying to paint a target on
exactly what that fear is, but I've learned by having a lot of crazy stuff
shoved into my face as a security researcher that if you can just get yourself
to focus on a task and start coding, a lot of contraptions that seem so hard
to build as to be implausible are actually the work of just a day or two; at
least, the kernel of those contraptions (emulators, hypervisors, compilers,
debuggers, drivers, interpreters, routing protocols, static analyzers).

If you have a basic aptitude for coding, not knowing how hard a task is isn't
a liability; it's a powerful asset. If you haven't actually done real work on
an OS, you _wish_ you thought it was as easy as this guy does.

~~~
commandar
When asked, "How could you possibly have done the first interactive graphics
program, the first non-procedural programming language, the first object
oriented software system, all in one year?" Ivan replied: "Well, I didn't know
it was hard."

<http://en.wikipedia.org/wiki/Ivan_Sutherland>

Worth noting that the person that asked him this was Alan Kay.

------
readme
If any of you naysayer arsehats (you know who you are) bothered reading to the
bottom of his article, you'd have seen that he has a section where you (if you
do indeed know about OS development) could help him by answering his
questions. I pasted it below for reference:

\-----------------------------------------------------------

My research

What I’ve found out so far:

Boot sequence: BIOS;

Master Boot Record (MBR);

Bootloader – the program that takes it over from MBR and loads your Kernel;

Kernel. How to write your own MBR and write it to Disk on windows.

I’ve written a small utility in Visual C++ that allows directly to read/write
from disk (download here, source included for Visual Studio 2010 Express);

How to write bare bones C kernel entry point.

How to write “naked” functions on Windows in Visual Studio

Missing link - I still don’t know how to properly step from MBR to Bootloader
to Kerlen, that is – write your own MBR code that would load bootloader, pass
the execution to bootloader that would load and pass execution to bare bones C
kernel:

What exactly is Global Descriptor Table (GDT) and Interrupt Descriptor Table
(IDT), and how it looks in C and Assembly? How and when, and again how, if
when is later (for example in Long Mode or Protected Mode) to set up all this
GDT and IDT stuff. They say you have to set it up before the kernel. Then they
say you can set it up with dummy values and set it up later in kernel. Then
they say, that to set it up, you have to be in Real Mode, so your kernel
(which might be way over 1Mb of real mode space), needs to switch between
modes. And then if your kernel is over 1Mb, you can’t access memory locations
after 1Mb, and so on… It’s confusing, but I’m going to find it out and post it
here later on.

How to handle Interrupts in C? Will they perform as callbacks that await some
return values or do I have to use inline assembly to process them correctly;

Is it possible to write MBR in C? I do understand that you still have to set
ORG to 7c00h, and use some specific assembly instructions, but if they could
be wrapped in C using inline assembly and C entry point can be glued with few
lines of assembly code, why not?

------
untog
I almost didn't post this comment because it makes me sound like such a
killjoy, but:

 _"I spend most of my days in the world of PHP, JavaScript (I love jQuery) and
a little bit of HTML, CSS and ActionScript 3.0. I’ve done some hobby software
development and also wrapped my head arround languages like C, C++ (except for
templates), C# and Java."_

It sounds like you don't have the experience required to make an OS. I
certainly don't either (I'm no C-head) so I am in no position to snark, but
you're going to fail in this endeavour.

That doesn't mean it's pointless, though- I think it'll be a tremendous
learning experience in getting to grips with the core of how computers
_actually_ work. So, good luck. Just don't go thinking you're going to make
the next Linux out of this.

EDIT: It's also important to note that the author didn't submit this to HN. He
didn't say "take this, HN amateurs!", he just posted something on his blog
that someone else picked up.

~~~
javajosh
You know what, if you have hesitation about posting something, then you
probably shouldn't. It's one thing to have a specific concern about his
project, but it's _quite another_ to call into question his skill as a
programmer and indeed quite arrogant to assume that you know what it takes to
build an OS.

There is a big difference between saying "You don't have what it takes" and
saying, "I think the obstacles you face will be very large, good luck!"

~~~
untog
_quite arrogant to assume that you know what it takes to build an OS_

With all of the (largely web/app-centric) development work that I have done,
there are numerous concepts in OS development that baffle me. I don't claim to
know what it takes to build an OS, but I know that it is beyond me.

Also, I wasn't questioning his skill as a programmer, I was questioning the
undertaking that he is discussing. _Any_ solo developer would struggle to
create an OS (especially when they have a full time job to contend with), let
alone someone that is going to have to learn a lot along the way. So my
suggestion was to go ahead, but treat it as a learning experience rather than
a deliverable product.

~~~
ricardobeat
Everyone that ever created an OS from scratch had to learn first. The only
question is how long it will take, but there is no reason to say "you will
fail".

------
Xcelerate
I think people are being overly pessimistic. It's not _that_ ambitious of a
project (particularly a hobby project at that). Why? Well, he doesn't have to
support thousands of different drivers and hardware configurations -- he only
needs code that supports his own. That eliminates a good chunk of the OS code.

Second, a lot of grunt-code can be found in open source projects, so most of
the tedious/time-consuming programming can be eliminated if he chooses to
follow this option.

Drop preemptive multitasking, cache-optimization, modes, virtual memory, and
networking and there's not too much left.

And finally, it doesn't take that long to understand the GDT. Mine became
corrupted once so I took a day to learn how it worked -- fixed that crap in a
hex editor.

So no, he's probably not going to invent the next highly polished OS that
handles every edge case and has been rigorously tested against bugs, but then
again I don't think it's unreasonable to see a simple little functional OS.

~~~
mje__
Sounds like you still don't understand the GDT :) [1]

I agre with you, though. As with any hobby project, picking the bits that are
interesting or fun makes it easy to keep going.

[1]<http://en.wikipedia.org/wiki/Global_Descriptor_Table> (maybe you're
thinking of the GPT?)

~~~
Xcelerate
D'oh. Slaps forehead.

------
kamme
Most of the comments seem so negative... When I was 16 I was also interested
in OS development and actually wrote a bootsector, a very small kernel and
support for fat12 in assembler. Previous experience? Basic and QBasic. It's
quite a good way to learn and it is possible when you take one step at a time
and are willing to spend some time reading... Your mind is a great tool, have
some faith in it.

------
robinh
Oh dear... overly ambitious plans, changing everything for the sake of change,
fearing assembly, using VS for OS development, and not even knowing how the
GDT and IDT work. There's so much wrong with this I don't even know where to
begin. I sense a doomed project.

~~~
mhurron
> using VS for OS development

What does Microsoft use?

~~~
munin
the last I heard (3-4 years ago), the OS/kernel team used emacs. the kernel
group has its own build infrastructure that is partially / mostly exported in
the DDK.

~~~
marshray
Untrue! I know "kernel people" who use Vim, too! :-)

However, my impression is most of them edit code in MSVC, build with the DDK
tools, and debug with windbg/ntsd/kd like most other driver developers.

------
steve8918
I don't think writing your own OS is as difficult as people are saying. You're
not trying to compete against Windows or Linux, you just want to get something
up and running. I'm sure bugs and crashes will be prevalent, but I'm sure it
would be a great project.

A really, really good book for this that I've read is "Developing Your Own
32-Bit Operating System" by Richard Burgess. It starts you from the beginning,
and walks you through all the steps in writing a really basic OS.

It's old and out of print, but it's definitely the best one I've seen.

Edit: I just found the website, they are offering the book free here:

<http://www.ipdatacorp.com/mmurtl.html>

~~~
bproctor
I've wrote my own OS back in the late '90s based heavily on this book.
Probably one of the best learning experiences I've had. I'm not sure how
relevant it is today. I'd love to see a second edition brought up to date.

------
drewmck
Please read Linus Torvald's book "Just for Fun: The Story of an Accidental
Revolution" [http://www.amazon.com/Just-Fun-Story-Accidental-
Revolutionar...](http://www.amazon.com/Just-Fun-Story-Accidental-
Revolutionary/dp/0066620732). It mostly deals with his experience building
Linux and the insane amount of work it took (he was a student at the time he
wrote the first version, with the help of hundreds of other people via
distributed development). It might give you some additional insight into the
effort involved.

------
wreckimnaked
> How to handle Interrupts in C? Will they perform as callbacks that await
> some return values or do I have to use inline assembly to process them
> correctly;

Not to disappoint you, but you should try doing some more low level
programming or dabbling with some existing OS code to have an idea how this
kind of programs look like. Maybe having a look at Minix for a reference of
simple OS?

Have you thought about targeting ARM? Its architecture may be way less
trickier than most Intel CPUs.

Well, good luck with that. Worst case scenario, you'll end up reading lots of
interesting resources.

~~~
wtracy
> Have you thought about targeting ARM? Its architecture may be way less
> trickier than most Intel CPUs.

Can anyone comment on whether this is really true?

~~~
wreckimnaked
When comparing the Intel 64 [1] and ARMv6[2] instruction sets that's a quite
trivial assumption. The difference on the number of instructions implemented
by those architecture reflects well the complexity gap between both.

Also, there are many other details that make targeting ARM much easier, for
instance the bootloading process on ARM is more straightforward with no BIOS
or EFI involved[3].

1:
[http://download.intel.com/products/processor/manual/325462.p...](http://download.intel.com/products/processor/manual/325462.pdf)

2:
[http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc....](http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0432c/CHDCICDF.html)

3: <http://www.keil.com/download/docs/52.asp>

------
forgottenpaswrd
Wow!!

Too ambitious. Doing that requires millions of dollars and tens of thousands
of man hours to make. How do I know? I do electronics and low level
programming work and I am really good at it. Just understanding the bugs that
manufactures put in hardware and then solve in software(because it is way
cheaper) takes a ton of work.

As I suppose he is not super rich, he will have to convince people to join
their project, a la Linus.

Good luck with that!! I really wish a clean-no backwards compatible OS were
real, I will add native OpenCL, OpenVG and OpenGL to the list, but my arachnid
sense tells me a person that does not use Unix will have a hard time getting
traction with geeks.

------
polymathist
UPDATE: The original author has posted a Part 2. Looks like he's already
started writing code and hitting milestones. <http://gusc.lv/2012/11/im-
writing-my-own-os-p2/>

------
robomartin
Anyone who has ever written a small RTOS on a small 8 bit embedded processor
will only laugh at the OP. And, I hate to say, it would be justified. There
are about twenty or thirty books between where he is now and where he'd have
to be in order to even start talking about designing an OS for a desktop
platform. Add to that 10,000 hours of coding low to high-level projects across
embedded to desktop platforms.

A quick read of the "About" page is probably in order:

<http://gusc.lv/about/>

What to say?

"Someone holding a cat by the tail learns something he can learn in no other
way" --Mark Twain.

Here's the tip of the tail:

[http://www.amazon.com/Embedded-Controller-
Forth-8051-Family/...](http://www.amazon.com/Embedded-Controller-
Forth-8051-Family/dp/0125475705)

[http://www.amazon.com/Operating-System-Concepts-Abraham-
Silb...](http://www.amazon.com/Operating-System-Concepts-Abraham-
Silberschatz/dp/1118112733/ref=dp_ob_title_bk)

[http://www.amazon.com/Performance-Preemptive-Multitasking-
Mi...](http://www.amazon.com/Performance-Preemptive-Multitasking-
Microprocessors-
Microcontrollers/dp/0982337531/ref=sr_1_2?s=books&ie=UTF8&qid=1353963610&sr=1-2&keywords=micro+c+os)

[http://www.amazon.com/Design-Operating-System-Prentice-
Hall-...](http://www.amazon.com/Design-Operating-System-Prentice-Hall-
Software/dp/0132017997/ref=sr_1_3?s=books&ie=UTF8&qid=1353963814&sr=1-3&keywords=operating+systems+design+and+implementation)

Have fun.

~~~
qznc
From a previous comment of yours: "Every new programmer needs to start with C.
In fact, I am convinced that every new programmer needs to start with C and be
tasked with writing an RTOS on a small memory-limited 8 bit processor. And
then write several applications that run within that RTOS."

He is not that far off from your suggestions. Why do you think 8bit and
realtime is better than AMD64? The architecture is a lot more complicated. On
the other it is probably much better documented as well.

~~~
derleth
> Every new programmer needs to start with C.

Wow, what an idiotic thing to say. C is one of the worst languages for
learning the actual fundamentals of programming, which are algorithms and data
structures.

~~~
javert
Coding algs and data structures in C lets you see how those things _actually
work_ in the computer. A lot is hidden by the abstractions of higher-level
languages.

In particular, I am thinking about pointers and memory management, but there
are other things.

~~~
robomartin
Yup. Exactly why I think C is a great starting point.

This is also why I think we have so much bloated code these days. Everything
has to be an object with a pile of methods and properties, whether you need
them or not. Meanwhile nobody seems to be able to figure out that you might be
able to solve the problem with a simple lookup table and clean, fast C code.
There was a blog post somewhere about exactly that example recently but I
can't remember where I saw it.

I wrote a GA in Objective-C because, well, I got lazy. Then, after seeing the
dismal performance I got I re-coded it in C. It's been a couple of years but I
think that the performance was hundreds of times faster than anything the
optimized Objective-C code could achieve. The heavy bloated NS data types just
don't cut it when it comes to raw performance.

Someone who has only been exposed to OO languages simply has no clue as to
what is happening when they are filling out the objects they are creating with
all of those methods and properties or instantiating a pile of them.

~~~
derleth
> This is also why I think we have so much bloated code these days.

'Bloat' is a snarl term. It's meaningless. It literally means nothing, except
to express negative emotion.

> I wrote a GA in Objective-C because, well, I got lazy. Then, after seeing
> the dismal performance I got I re-coded it in C.

Did you try any other algorithms? Any other data structures? Simply picking a
new language is laziness.

~~~
robomartin
No, it's not a snarl term. It's very real.

When dealing win an array is 400 times slower in a "modern OO language" then
in raw C, well, the code id fucking bloated.

When you can use a simple data structure and some code to solve a problem and,
instead, write an object with a pile of properties and methods because, well,
that's all you know, that's bloated code.

Of course there are lots of places where OO makes absolute sense. And the fat
and slow code is the compromise you might have to make. That's the way it
goes.

With regards to my GA example. No, I had to implement a GA. That's what was
required to even attempt to solve the problem at hand. Later on we used it to
train a NN, which made the ultimate solution faster. But, the GA was required.
There was no way around it and Objective-C was such a an absolute pig at it
that it made it unusable.

> Simply picking a new language is laziness

See, there's the difference. I started programming at a very low level and
have experienced programming languages and approaches above that, from C, to
C++, Forth, Lisp, APL, Python, Java, etc.

I have even done extensive hardware design with reconfigurable hardware like
PLD, PLA's and FPGA's using Verilog/VHDL. I have designed my own DDR memory
controllers as well as raw-mode driver controllers and written all of the
driver software for the required embedded system. My last design was a
combination embedded DSP and FPGA that processed high resolution image data in
real time at a rate of approximately SIX BILLION bytes per second.

So, yes, I am an idiot and make really fucking dumb suggestions.

Because of that I would like to think that, if the choice exists --and very
often it does not-- I do my best to pick the best tool for the job.

More often than not, when it's pedal-to-the-metal time C is the most sensible
choice. It used to be that you had to get down to assembler to really optimize
things, but these days you can get a way with a lot if C is used smartly.

~~~
derleth
> When dealing win an array is 400 times slower in a "modern OO language" then
> in raw C, well, the code id fucking bloated.

Social science numbers do not impress me. Besides, what is a "modern OO
language"? Haskell? How can you give any numbers without even specifying that
detail?

> Of course there are lots of places where OO makes absolute sense. And the
> fat and slow code is the compromise you might have to make.

Your idea that "OO = fat and slow" is blown away by actual benchmarks.

<http://www.haskell.org/haskellwiki/Shootout>

(And, yes, unless and until you define what "OO" is to you, I'll pick Haskell
as a perfectly reasonable OO language. Given than I've seen C called OO by
people with better writing skills than you, this is hardly a strange choice in
this context.)

> So, yes, I am an idiot

Again, I did not call you an idiot. The only one calling you an idiot here is
you.

> More often than not, when it's pedal-to-the-metal time C is the most
> sensible choice.

I agree fully with this. However, I disagree that "pedal-to-the-metal time" is
all of the time, or even most of the time. _Especially_ when you're trying to
teach programming.

Do you teach new drivers in an F1 racecar? Why or why not?

------
mvzink
Looks like you haven't even started thinking about the problems you'll run
into architecting the actual mechanisms and policies of the operating system;
process scheduling, virtual memory, etc. That's probably for the better—one
thing at a time. For when you do get to that stage, I recommend Operating
Systems: Three Easy Pieces. <http://pages.cs.wisc.edu/~remzi/OSTEP/>

------
gusc
Holly jumping Jesus … I just got my 15 minutes of shame/fame over the
internet. I linked my “just write down what you’re thinking” blog post on
dzone.com and somehow it got posted on Hacker News and from there … Shit just
hit the fan. It seems that writing “I’m writing my own OS” as a blog title can
be translated from “I have spare time, I want to try out new things” into
“Fuck this shit, I’m going for a revolution!!!” It’s time consuming to answer
all the comments I’ve gained, so I’m writing this post as an answer to all of
you.

<http://gusc.lv/2012/11/im-writing-my-own-os-intermission/>

And thank you again for inspiration (even the cynicism is inspirational ;)

------
mimog
Nope. If you want to know how to make a small OS that can run on a PC, take a
look at xv6 which is a modern re-implementation of the sixth edition of Unix
and is on Github. You can compile it and then run it in qemu. Fork it, read
and understand the source and then expand upon it to your hearts content. That
would at least give a very good starting point.

------
chewxy
There is a surprising amount of negativity coming from what I expect to be a
'hacker' crowd. This kid (he's 30 can I call him a kid?) has ambition and what
appears to be the drive to create his own OS - I mean, if you read the bottom
of his page, he did some research (sure, wiki-ing them is not equal to
actually understanding them), but it at least shows willingness to learn, and
we should not be putting him down at all.

Sometimes the HN crowd surprises me. We pride ourselves in being hackers, most
often idealistic (bitcoins and patent law change anyone?) but when a singular
person shows idealistic ambition, we immediately engage in poppy cutting.

Sigh.

~~~
Deestan
I think his enthusiasm and attempts are good things.

But. His post is just that - his expression of enthusiasm. There's not much of
anything else here yet. We have nothing to discuss but his enthusiasm.

Having seen these kinds of ideas consistently end up as "well... it got hard"
a week later, it triggers my grumpy "sure whatever let me know how it goes in
a month" reflex.

------
endlessvoid94
I'll be following this. Don't listen to the hate -- dive in, I'm sure you'll
learn a ton, and maybe build something useful for yourself and others.

This is the exact definition of hacking, if you ask me.

------
munin
Implementing an OS is hard work, even if you build on the very hard work of
those who have tried before you in terms of APIs, abstraction layers, etc. It
doesn't sound like you have a lot of familiarity with low-level software
development, or software development in general, so you just took a "hard
mode" project and cranked it up to "nightmare".

Generally this is a bad idea because without any external motivation, you lose
interest and stop working. With external motivation is worse, because you can
burn out and become a catatonic shell of a person, staring absently into space
for the rest of your life.

Just some FYIs:

> On the side note - It’s 21st century, but our PCs are still booting up as
> old-fart Intel 8086.

You should read about EFI
([http://www.intel.com/content/www/us/en/architecture-and-
tech...](http://www.intel.com/content/www/us/en/architecture-and-
technology/unified-extensible-firmware-interface/efi-homepage-general-
technology.html))

You should also read all of the lecture materials from good universities OS
classes. In those classes, you basically do this. Some classes are more guided
than others. Some places to start:

\- CMU: <http://www.cs.cmu.edu/~410/>

\- UMD: <https://www.cs.umd.edu/~shankar/412-F12/>

UMD uses a toy operating system called GeekOS that the students extend. You
might find browsing its source code useful
(<http://code.google.com/p/geekos/>)

Good luck!

~~~
willscott
There are a bunch of teaching OSes which are a great place to start for this
stuff.

The actively developed ones we chose between when teaching the OS class at UW
this fall were:

JOS (mit) <https://github.com/guanqun/mit-jos>

Pintos (stanford) <http://www.stanford.edu/class/cs140/projects/>

OS161 (harvard) <http://www.eecs.harvard.edu/~syrah/os161/>

------
sourc3
This is pretty interesting. I find this type of behavior to be everywhere in
the software world. If I cannot figure something out with a platform, let me
re-write it. Interesting observation is that the number of these "re-writes"
is inversely proportional to the experience of the person proposing these
ideas.

Good luck to the author, nonetheless it will be a good learning experience for
him.

~~~
geoka9
Also interesting is that once you start re-writing and bump into hard issues,
you decide to take a peek at how others have solved them, you eventually find
yourself understanding the platform you're trying to re-write and realize that
maybe that platform is not as bad as you thought it were.

"Those who don't understand Unix are condemned to reinvent it, poorly."

------
robomartin
On threads such as this one it is easy --and even popular-- to dump on those,
such as myself, who come down on the "nay" side, even when this is firmly
based on experience and having made plenty of mistakes in the field.

The linked article does NOT talk about a one-semester school project or a
quick-and-simple learning OS.

No, the article talks about a web developer with no real experience writing
low-level code not only wanting to bootstrap every single device driver but
also ignoring years of accumulated knowledge and code libraries to write an OS
that boots directly into graphical mode, does not take advantage of POSIX and
more.

There's nothing wrong with the "How hard can it be?" approach to learning.
I've done this many times. And almost every single time I came away with "I
sure learned a lot, but what the fuck was I thinking?". The last time I pulled
one of those was about fifteen years ago and the "three month project" took
nearly two years.

What he is talking about is more complex than writing the Linux kernel from
scratch because he wants to re-invent everything. Here are some stats on the
Linux kernel:

[http://royal.pingdom.com/2012/04/16/linux-kernel-
development...](http://royal.pingdom.com/2012/04/16/linux-kernel-development-
numbers/)

Even if his project was 10% of this it would still be a grotesque
miscalculation for a single developer, otherwise employed and without the
experience to back-up some of what he is proposing.

If, on the other hand, the post had suggested something like this it would
have been far more reasonable an idea:

"Hey, I just spent a year implementing everything in the Tanenbaum book. Now I
would like to start from that base and enhance the OS to make it do this...".

Let's compare notes in a year and see how far he got.

------
readymade
I could have guessed this would turn into a massive flamefest, but c'mon
people. So what if he's green? This will be a learning experience for him. And
I'll hazard that in the end, even if he never ends up writing a whole OS from
scratch, that he will have gained more valuable low level experience than the
vast majority of those here.

------
bitteralmond
I agree that this project is hugely ambitious for one man. So was Linux. Linus
recruited a bunch of other hobby programmers to help him make it. Although he
may be jumping the gun on announcing it, he's got a lot of good ideas about
stripping back all the obfuscation that's resulted from 30 years of stacking
things onto the same old conventions and wiggling them around until they fit.

I'm sure the idea of building a modern OS that is straightforward and written
in a simple, popular language like C (and possibly Python later for higher-
level stuff) will appeal to a wide range of people who will all want to help.
I'd love to see this project happen, and if the day comes where Gusts is
calling for help, I'll be right there in line to help him make this.

------
happywolf
The Unix/Linux systems are designed by a lot of very smart people and have
gone through many iterations. No doubt they do have some historical baggage,
but, there are good reasons why the current design is as-is. Not trying to
learn the history will doomed to repeat it.

------
mrng
"I still don’t understand the meaning and differences between /bin, /usr/bin
and /usr/local/bin"

Oh. OK, then.

------
agumonkey
I hope you know plan9 or other OSes beside *nix/POSIX so you have a larger
field of view.

If I had crossed the desire threshold to start that project (#1 project in my
mind since I left college) I'd leave the C ecosystem altogether, design a
typed ,functional ,binary friendly, modular, subset of C (and probably be
forever alone). Something in the groove of
<http://en.wikipedia.org/wiki/BitC>, even though its talented author concluded
it wasn't a successful path.

------
desireco42
I think his critique of linux files layout and other points made are
completely spot on. Me and I am sure others often were thinking how it would
be great if things were different. I happen to know why those folders are
named as they are, and they are completely arbitrary. He also started on it,
did some initial progress. So he did a php before, boo-hoo.

I would prefer he decided to fork linux and change things he didn't like, then
start from skratch. However, there is a great value starting from scratch. I
wish I had a life :) to join him and figure out things together, it would be a
blast, how many times in your life you have a chance to work on actual modern
OS.

I believe it is totally possible for him to accomplish what he started, if
knowledgeable people would join him and work with project together. Today with
amazing tools, it is good time to create a new OS that would have modern
tooling.

I wrote recently on my blog about a need for developer distribution of linux.
Strangely this is still missing.
[http://softwaredevelopmentinchicago.com/2012/10/17/ubuntu-
al...](http://softwaredevelopmentinchicago.com/2012/10/17/ubuntu-all-the-
missed-chances/)

It is great that we are discussing this. That is how things start.

------
nnq
Short advice: find a compiler that supports modern decent C (C99), NOT VS
(<http://www.infoq.com/news/2012/05/vs_c99_support/>) - may not be relevant
for your kernel code that much, but at least at the end of your adventure you
will have learned how to write good modern C (and no, C it not dead and
replaced by C++, they are languages with different philosophies and used by
different kinds of programmers and they are both evolving on they own route,
despite FUD originating from Microsoft and other sources)

...and when you reach to the GUI part, do the same for C++, use the latest
version and language features: I've heard that VS2012 lasts upgrade got closer
to it, but google around before settling on it

...or to keep it simpler: better use GCC compilers (since the Linux kernel is
built with it, you should find enough compiler specific docs and related tools
too)

------
jff
Take care when writing your own bootloader, or you may find yourself
essentially maintaining two separate kernel trees.

------
zanny
I love little thought experiments like this, so heres my 2 cents:

1\. Targeting a modern architecture is good, but if I were being this
ambitious, I would wager having such a backwards compatable burdened
architecture like x86_64 (even when it is highly performant just through raw
funding dollars) I would still rather start at square 1 on some risc 64 bit
virtual 48 bit physical word system. Go even further, and design such a
hardware ecosystem with heterogeneous computing built into the foundations -
have arbitrary numbers of ALUs and FPUs and have different pipeline structures
allowing for various degrees of SIMD parallelism across some tightly
integrated weak cores and more heavily pipelined and bulkier serial cores, and
have an intelligent enough instruction set to allow for scheduling (or even
better, the hardware itself) to recognize parallel tasks and execute them with
varying degrees of parallelism. Take AMD Fusion or Tegra to the next level and
instead of having a discrete gpu and cpu on one die mash them together and
share all the resources.

2\. I'd kick C out. If I'm going with a new architecture, I need to write the
compiler from scratch anyway. I might consider LLVM for such a system, just
because the intermediary assembly layer is intentionally lossless and allows
for backwards language compatability with everything under the sun right now.
But ditch C, take modern language concepts from C++, Python etc, and cut down
on the glyphic syntax and try rethinking the distribution of special
characters (I think pointer<int> c makes more sense than int (star)c, for
example - go even further, and provide 3 levels of verbosity for each concept,
like pointer<int32> c, ptr<int32> c, and &:i32 c). I would definitely want to
fix standard type sizes at the least, having things like i32 integers instead
of the int type being 16 or 32 bit, etc, with some more modern niceities like
the D style real float that uses the architecture restricted maximum FPU
register size).

3\. Screw UEFI, mainly because it is a design by consortium concept - it is
inherently cumbersome because it was a commitee project between industry
giants rather than a revolution in booting. I do like cutting down on legacy
interfaces, I'd go even further and try to minimize my system to (in theory)
one serial transport and one digital, maybe 4, with unidirectional and
bidirectional versions of both, and maybe support for some classic analog
busses (like audio, which doesn't make much sense to transport in digital
format, although I haven't looked into it much). Everything plug and play,
everything attempting to provide power over a channel so you don't need
additional power connectivity if you can avoid it. For the BIOS, I would
replace it with some metric of scan busses for profiles -> incite some kind of
device-wise self test -> provide device information in memory to the payload
binary, to allow memory mapping and all the other goodness. Maybe even have
the bios itself act as a sub-kernel and provide the mapping itself. Maybe even
fork the kernel, and treat it like some kind of paravirtualized device
environment where the bios never overrides itself with the payload but instead
stays active as a device interface. Saves a lot of code redundancy between the
two then. It would of course have an integrated bootloader and the ability to
parse storage device trees for some bootable material. Maybe have file system
standards where each partition has a table of pointers to loadable binaries
somewhere, or maybe stick them in some partition table entry (obviously not a
FS expert here).

4\. Screw URIs, go straight for a kernelwise VFS that can reference
_everything_. I'd love to see /net/<IP address>/ referening the top level of
some remote servers public resources. You could have a universal network
protocol where each connection is treated as a virtual mount, and individual
files (and everything is a file, of course) can dictate if they use streamed
or packet based data off some network transaction about the base protocol. So
instead of having <http://google.com>, you could use /net/google.com/ which
when opened does DNS resolution in the VFS to 74.125.224.72 (well, ipv6,
obviously - we are talking about a _new_ OS here, so 2001:4860:8006::62 - and
as a side note, I would _never_ try to get rid of IP as the underlying
transport protocol - as insane I might be about redesigning hardware and
rethinking stuff people much smarter than myself came up with, I know you will
_never_ ursurp IP as _the_ network trasport everyone uses to connect the world
ever). And then when you open google.com/search, you open a remote file that
interprets the "arguements" of ?q=baconatorextreme on the extension into the
returned page file that you access.

I agree with getting rid of Unix directories, they are outdated crappy, and
all their names make no sense. However, /bin is meant to be system required
binaries to boot, where sbin is root utility binaries, /usr/bin is general
purpose executables that might not be local to the machine and might be a
remote mount, and /usr/local/bin is the local machines installed binaries. Of
course these polcies are never abided by, and they still have /etc,
/usr/games, and a bunch of other folders to make life a hassle.

That's enough rates for a HN comment thread though, I'll stop and spare y'all
:P

~~~
bstpierre
> I would still rather start at square 1 on some risc 64 bit virtual 48 bit
> physical word system.

A friend of mine wrote a little OS (similar to vxWorks) for 64-bit MIPS in the
90s; I helped him debug a couple of problems. This was actual production code
to go in a product (our employer was too cheap to license vxWorks for the
secondary processor in the product).

It's incredibly easy to get something up and running on an architecture like
this. (Admittedly he cheated by virtue of not needing to interface with hw to
get loaded -- everything gets much easier when your EEPROM is wired to the
boot vector.) Get your kernel data structures set up, handle interrupts, and
BOOM! you've got multitasking. (I think it took him about a week.)

------
olalonde
I am reminded of <http://www.sparrowos.com/> (aka losethos).

------
pshc
I'd like to see someone try re-inventing a minimalist userspace. Create an OS
running on the Linux kernel without coreutils, binutils etc., and see how far
you can go.

If you strip out loadable module support and such, is it possible to boot
without the usual POSIX support structure? Without filesystems?

~~~
vidarh
I ported Linux to an embedded system that booted straight into ash (minimal
shell). Other than ash, it only had custom applications. We didn't bother with
a separate init app even - ash served that role sufficiently well.

Linux has very minimal requirements of userspace - pretty much you need to
have a process that will act as your init process that knows to wait to clean
up any zombine processes now and again. The rest is pretty much up to how you
want to organize things.

------
husam212
Writing new OS entirely from scratch? without any intention to rely on some
useful parts of previous projects? This is literally what we call "Reinventing
The Wheel", and if you go through human history you will find that this is
absolutely NOT the best way of development.

~~~
readymade
If that were true then there would only be one wheel design in all of human
history.

------
guilloche
As many people here said, this guy may not know what he doesn't know. But I am
admiring his braveness and it is good thing for someone to shoulder off all
legacy burdens and start a fresh OS.

As a developer, I have similar feeling on softwares including OSes, and I
started a fresh vector editor project(Torapp guilloche online designer
<http://www.torapp.info>), I know a vector editor is much simpler than an OS,
but it is also pretty complicated. When designing the editor, I learned a lot
and changed designs multiple times. I am sure that guy will learn and even if
he can not complete an OS, he may leave some well-designed code base for other
people to start with.

------
robomartin
OK, if you don't have any real experience in low-level embedded coding
(relevant to device drivers), RTOS or OS design in general, file systems, data
structures, algorithms, interfaces, etc. And, if you have "hobby level"
experience with Assembler, C and C++. And, if your intent is to write a
desktop OS, from the ground up, without making use of existing technologies,
drivers, file systems, memory management, POSIX, etc. Here's a list of books
that could be considered required reading before you can really start to write
specifications and code. Pick twenty of these and that might be a good start.

In no particular order:

1- [http://www.amazon.com/C-Programming-Language-2nd-
Edition/dp/...](http://www.amazon.com/C-Programming-Language-2nd-
Edition/dp/0131103628/ref=pd_bxgy_b_img_y)

2- [http://www.amazon.com/The-Answer-Book-Solutions-
Programming/...](http://www.amazon.com/The-Answer-Book-Solutions-
Programming/dp/0131096532/ref=pd_sim_b_2)

3- [http://www.amazon.com/The-Standard-Library-P-J-
Plauger/dp/01...](http://www.amazon.com/The-Standard-Library-P-J-
Plauger/dp/0131315099/ref=pd_sim_b_3)

4- [http://www.amazon.com/C-Traps-Pitfalls-Andrew-
Koenig/dp/0201...](http://www.amazon.com/C-Traps-Pitfalls-Andrew-
Koenig/dp/0201179288/ref=pd_sim_b_8)

5- [http://www.amazon.com/Expert-Programming-Peter-van-
Linden/dp...](http://www.amazon.com/Expert-Programming-Peter-van-
Linden/dp/0131774298/ref=pd_sim_b_2)

6- [http://www.amazon.com/Data-Structures-In-Noel-
Kalicharan/dp/...](http://www.amazon.com/Data-Structures-In-Noel-
Kalicharan/dp/1438253273/ref=pd_sim_b_9)

7- [http://www.amazon.com/Data-Structures-Using-Aaron-
Tenenbaum/...](http://www.amazon.com/Data-Structures-Using-Aaron-
Tenenbaum/dp/0131997467/ref=pd_sim_b_2)

8- [http://www.amazon.com/Mastering-Algorithms-C-Kyle-
Loudon/dp/...](http://www.amazon.com/Mastering-Algorithms-C-Kyle-
Loudon/dp/1565924533/ref=pd_sim_b_14)

9- [http://www.amazon.com/Code-Complete-Practical-Handbook-
Const...](http://www.amazon.com/Code-Complete-Practical-Handbook-
Construction/dp/0735619670/ref=pd_sim_b_53)

10- [http://www.amazon.com/Design-Patterns-Elements-Reusable-
Obje...](http://www.amazon.com/Design-Patterns-Elements-Reusable-Object-
Oriented/dp/0201633612/ref=pd_sim_b_3)

11- [http://www.amazon.com/The-Mythical-Man-Month-Engineering-
Ann...](http://www.amazon.com/The-Mythical-Man-Month-Engineering-
Anniversary/dp/0201835959/ref=pd_sim_b_11)

12- [http://www.amazon.com/The-Programming-Language-4th-
Edition/d...](http://www.amazon.com/The-Programming-Language-4th-
Edition/dp/0321563840/ref=pd_sim_b_5)

13- [http://www.amazon.com/The-Standard-Library-Tutorial-
Referenc...](http://www.amazon.com/The-Standard-Library-Tutorial-
Reference/dp/0321623215/ref=pd_bxgy_b_text_y)

14- [http://www.amazon.com/API-Design-C-Martin-
Reddy/dp/012385003...](http://www.amazon.com/API-Design-C-Martin-
Reddy/dp/0123850037/ref=pd_sim_b_6)

15- [http://www.amazon.com/The-Linux-Programming-Interface-
Handbo...](http://www.amazon.com/The-Linux-Programming-Interface-
Handbook/dp/1593272200/ref=pd_sim_b_8)

16- [http://www.amazon.com/Computer-Systems-Programmers-
Perspecti...](http://www.amazon.com/Computer-Systems-Programmers-Perspective-
Edition/dp/0136108040/ref=pd_sim_b_1)

17- [http://www.amazon.com/System-Programming-Unix-Adam-
Hoover/dp...](http://www.amazon.com/System-Programming-Unix-Adam-
Hoover/dp/0136067123/ref=pd_sim_b_4)

18- [http://www.amazon.com/Memory-Programming-Concept-
Frantisek-F...](http://www.amazon.com/Memory-Programming-Concept-Frantisek-
Franek/dp/0521520436/ref=pd_sim_b_2)

19- [http://www.amazon.com/Memory-Management-Implementations-
Prog...](http://www.amazon.com/Memory-Management-Implementations-Programming-
Development/dp/1556223471/ref=pd_sim_b_3)

20- [http://www.amazon.com/UNIX-Filesystems-Evolution-Design-
Impl...](http://www.amazon.com/UNIX-Filesystems-Evolution-Design-
Implementation/dp/0471164836/ref=pd_sim_b_16)

21- [http://www.amazon.com/PCI-System-Architecture-4th-
Edition/dp...](http://www.amazon.com/PCI-System-Architecture-4th-
Edition/dp/0201309742/ref=pd_sim_b_1)

22- [http://www.amazon.com/Universal-Serial-System-
Architecture-E...](http://www.amazon.com/Universal-Serial-System-Architecture-
Edition/dp/0201309750/ref=pd_sim_b_3)

23- [http://www.amazon.com/Introduction-PCI-Express-Hardware-
Deve...](http://www.amazon.com/Introduction-PCI-Express-Hardware-
Developers/dp/0970284691/ref=pd_sim_b_4)

24- [http://www.amazon.com/Serial-Storage-Architecture-
Applicatio...](http://www.amazon.com/Serial-Storage-Architecture-Applications-
High-Performance/dp/0971786186/ref=pd_sim_b_2)

25- [http://www.amazon.com/SATA-Storage-Technology-Serial-
ATA/dp/...](http://www.amazon.com/SATA-Storage-Technology-Serial-
ATA/dp/0977087816/ref=pd_sim_b_1)

26- [http://www.amazon.com/Beyond-BIOS-Developing-Extensible-
Inte...](http://www.amazon.com/Beyond-BIOS-Developing-Extensible-
Interface/dp/1934053295/ref=pd_sim_b_7)

27- [http://www.amazon.com/Professional-Assembly-Language-
Program...](http://www.amazon.com/Professional-Assembly-Language-
Programmer/dp/0764579010/)

28- [http://www.amazon.com/Linux-Kernel-Development-3rd-
Edition/d...](http://www.amazon.com/Linux-Kernel-Development-3rd-
Edition/dp/0672329468/ref=pd_sim_b_6)

29- [http://www.amazon.com/Version-Control-Git-collaborative-
deve...](http://www.amazon.com/Version-Control-Git-collaborative-
development/dp/1449316387/)

30- [http://www.amazon.com/Embedded-Software-Primer-David-
Simon/d...](http://www.amazon.com/Embedded-Software-Primer-David-
Simon/dp/020161569X/ref=pd_sim_b_6)

31- [http://www.amazon.com/Programming-Embedded-
Systems-C/dp/1565...](http://www.amazon.com/Programming-Embedded-
Systems-C/dp/1565923545/ref=pd_sim_b_4)

32- [http://www.amazon.com/Making-Embedded-Systems-Patterns-
Softw...](http://www.amazon.com/Making-Embedded-Systems-Patterns-
Software/dp/1449302149/ref=pd_sim_b_2)

33- [http://www.amazon.com/Operating-System-Concepts-Abraham-
Silb...](http://www.amazon.com/Operating-System-Concepts-Abraham-
Silberschatz/dp/1118112733/ref=dp_ob_title_bk)

34- [http://www.amazon.com/Performance-Preemptive-Multitasking-
Mi...](http://www.amazon.com/Performance-Preemptive-Multitasking-
Microprocessors-Microcontrollers/dp/0982337531/)

35- [http://www.amazon.com/Design-Operating-System-Prentice-
Hall-...](http://www.amazon.com/Design-Operating-System-Prentice-Hall-
Software/dp/0132017997/)

36- [http://www.amazon.com/Unix-Network-Programming-Sockets-
Netwo...](http://www.amazon.com/Unix-Network-Programming-Sockets-
Networking/dp/0131411551/)

37- [http://www.amazon.com/TCP-Illustrated-Volume-Addison-
Wesley-...](http://www.amazon.com/TCP-Illustrated-Volume-Addison-Wesley-
Professional/dp/0321336313/ref=pd_sim_b_2)

38- [http://www.amazon.com/TCP-IP-Illustrated-Vol-
Implementation/...](http://www.amazon.com/TCP-IP-Illustrated-Vol-
Implementation/dp/020163354X/ref=pd_sim_b_5)

39- [http://www.amazon.com/TCP-Illustrated-Vol-Transactions-
Proto...](http://www.amazon.com/TCP-Illustrated-Vol-Transactions-
Protocols/dp/0201634953/ref=pd_sim_b_5)

40- [http://www.amazon.com/User-Interface-Design-Programmers-
Spol...](http://www.amazon.com/User-Interface-Design-Programmers-
Spolsky/dp/1893115941/)

41- [http://www.amazon.com/Designing-Interfaces-Jenifer-
Tidwell/d...](http://www.amazon.com/Designing-Interfaces-Jenifer-
Tidwell/dp/1449379702/)

42- [http://www.amazon.com/Designing-Interfaces-Jenifer-
Tidwell/d...](http://www.amazon.com/Designing-Interfaces-Jenifer-
Tidwell/dp/1449379702/)

43- [http://www.amazon.com/Programming-POSIX-Threads-David-
Butenh...](http://www.amazon.com/Programming-POSIX-Threads-David-
Butenhof/dp/0201633922/ref=sr_1_4?s=books&ie=UTF8&qid=1353993641&sr=1-4&keywords=multithreaded+programming)

44- [http://www.intel.com/p/en_US/embedded/hwsw/software/hd-
gma#d...](http://www.intel.com/p/en_US/embedded/hwsw/software/hd-
gma#documents)

45-
[http://www.intel.com/content/www/us/en/processors/architectu...](http://www.intel.com/content/www/us/en/processors/architectures-
software-developer-manuals.html)

46-
[http://www.intel.com/p/en_US/embedded/hwsw/hardware/core-b75...](http://www.intel.com/p/en_US/embedded/hwsw/hardware/core-b75/hardware)

47- <http://www.hdmi.org/index.aspx>

48- <http://en.wikipedia.org/wiki/Digital_Visual_Interface>

49- [http://www.amazon.com/Essential-Device-Drivers-
Sreekrishnan-...](http://www.amazon.com/Essential-Device-Drivers-Sreekrishnan-
Venkateswaran/dp/0132396556/)

50- [http://www.amazon.com/Making-Embedded-Systems-Patterns-
Softw...](http://www.amazon.com/Making-Embedded-Systems-Patterns-
Software/dp/1449302149/)

51- [http://www.amazon.com/Python-Programming-Introduction-
Comput...](http://www.amazon.com/Python-Programming-Introduction-Computer-
Science/dp/1590282418/)

52- [http://www.amazon.com/Practical-System-Design-Dominic-
Giampa...](http://www.amazon.com/Practical-System-Design-Dominic-
Giampaolo/dp/1558604979/)

53- [http://www.amazon.com/File-Systems-Structures-Thomas-
Harbron...](http://www.amazon.com/File-Systems-Structures-Thomas-
Harbron/dp/0133147096/ref=pd_sim_b_3)

54- ...well, I'll stop here.

Of course, the equivalent knowledge can be obtained by trial-and-error, which
would take longer and might result in costly errors and imperfect design. The
greater danger here is that a sole developer, without the feedback and
interaction of even a small group of capable and experienced programmers could
simply burn a lot of time repeating the mistakes made by those who have
already trenched that territory.

If the goal is to write a small RTOS on a small but nicely-featured
microcontroller, then the C books and the uC/OS book might be a good shove in
the right direction. Things start getting complicated if you need to write
such things as a full USB stack, PCIe subsystem, graphics drivers, etc.

~~~
derefr
> If the goal is to write a small RTOS on a small but nicely-featured
> microcontroller, then the C books and the uC/OS book might be a good shove
> in the right direction. Things start getting complicated if you need to
> write such things as a full USB stack, PCIe subsystem, graphics drivers,
> etc.

I've always wondered if there could be created some way to skip this step in
[research] OS prototyping, by creating a shared library (exokernel?) of just
drivers, while leaving the "design decisions" of the OS (system calls, memory
management, scheduling, filesystems, &c.--you know, the things people get into
OS development to play with) to the developer.

People already sort of do this by targeting an emulator like VirtualBox to
begin with--by doing so, you only (initially) need one driver for each feature
you want to add, and the emulator takes care of portability. But this approach
can't be scaled up to a hypervisor (Xen) or KVM, because those expect their
guest operating systems to also have relevant drivers for (at least some of)
the hardware.

I'm wondering at this point if you could, say, fork Linux to strip it down to
"just the drivers" to start such a project (possibly even continuing to merge
in driver-related commits from upstream) or if this would be a meaningless
proposition--how reliant are various drivers of an OS on OS kernel-level
daemons that themselves rely on the particular implementation of OS process
management, OS IPC, etc.? Could you code for the Linux driver-base without
your project growing strongly isomorphic structures such as init, acpid, etc.?

Because, if you could--if the driver-base could just rely on a clean,
standardized, exported C API from the rest of the kernel, then perhaps (and
this is the starry-eyed dream of mine) we could move "hardware support
development" to a separate project from "kernel development", and projects
like HURD and Plan9 could "get off the ground" in terms of driver support.

~~~
robomartin
A lot depends on the platform. If the OS is for a WinTel motherboard it is one
thing. If, however, the idea is to bypass driver development for a wide range
of platforms it gets complicated.

In my experience one of the most painful aspects of bringing up an OS on a new
platform is exactly this issue of drivers as well as file systems. A little
google-ing quickly reveals that these are some of the areas where one might
have to spend big bucks in the embedded world in order to license such modules
as FFS (Flash File System) with wear leveling and other features as well as
USB and networking stacks. Rolling your own as a solo developer or even a
small team could very well fit into the definition of insanity. I have done a
good chunk of a special purpose high-performance FFS. It was an all-absorbing
project for months and, realistically, in the end, it did not match all of the
capabilities of what could be had commercially.

This is where it is easy to justify moving into a more advanced platform in
order to be able to leverage Embedded Linux. Here you get to benefit and
leverage the work of tens of thousands of developers devoted to scratching
very specific itches.

The down-side, of course, is that if what you need isn't implemented in the
boad support package for the processor you happen to be working with, well,
you are screwed. The idea that you can just write it yourself because it's
Linux is only applicable if you or your team are well-versed in Linux dev at a
low enough level. If that is not the case you are back to square one. If you
have to go that route you have to hire an additional developer that knows this
stuff inside out. That could mean $100K per year. So now your are, once again,
back at square one: hiring a dev might actually be more exoensive than
licensing a commercial OS with support, drivers, etc.

I was faced with exactly that conundrum a few years ago. We ended-up going
with Windows CE (as ugly as that may sound). There are many reasons for that
but the most compelling one may have been that we could identify an OEM board
with the right I/O, features, form factor, price and full support for all of
the drivers and subsystems we needed. In other words, we could focus on
developing the actual product rather than having to dig deeper and deeper into
low-level issues.

It'd be great if low level drivers could be universal and platform independent
to the degree that they could be used as you suggest. Obviously VM-based
platforms like Java can offer something like that so long as someone has done
the low-level work for you. All that means is that you don't have to deal with
the drivers.

To go a little further, part of the problem is that no standard interface
exists to talk to chips. In other words, configuring and running a DVI
transmitter, a serial port and a Bluetooth I/F are vastly different even when
you might be doing some of the same things. Setting up data rates, clocks,
etc. can be day and night from chip to chip.

I haven't really given it much thought. My knee-jerk reaction is that it would
be very hard to crate a unified, discoverable, platform-independent mechanism
to program chips. The closest one could possibly approach this idea would be
if chip makers were expected to provide drivers written to a common interface.
Well, not likely or practical.

Not an easy problem.

~~~
derefr
> It'd be great if low level drivers could be universal and platform
> independent to the degree that they could be used as you suggest. Obviously
> VM-based platforms like Java can offer something like that so long as
> someone has done the low-level work for you. All that means is that you
> don't have to deal with the drivers.

Another thought: if not just a package of drivers, then how stripped down (for
the purpose of raw efficiency) could you make an operating system intended
only to run an emulator (IA32, JVM, BEAM, whatever) for "your" operating
system? Presumably you could strip away scheduling, memory security, etc.
since the application VM could be handling those if it wanted to. Is there
already a major project to do this for Linux?

------
Geee
Good luck, I certainly hope you don't end up like losethos.

------
olgeni
> No Unix directory tree. I hate it – it does not say anything to a user

Actually it has a lot to say, but in this case it just appealed to the fifth
amendment.

~~~
ante_annum
This is one of those times that the phrase "RTFM" actually makes sense. If the
author had read what each one was rather than guessing, he'd have enjoyed it
all a lot more. Nobody likes typing out "/system/configurations/networking".
That's why they wound up with things like "/sys/conf/net". But hey, if he
succeeds, maybe he'll come around.

~~~
fyolnish
Do you have any reason to assume he won't implement tab completion? Sure
doesn't take long to write out /System/Library/[..] on os x

------
merlish
Good luck, have fun.

------
jiggy2011
Won't be big and professional like gnu.

Seriously though, good luck.

------
exDM69
This guy is slightly clueless but he has the spirit. I've written my own hobby
operating system skeleton and it was a very good learning experience.

Here's a few notes about his plans:

    
    
      > Target modern architecture
      > Avoid legacy, drop it as fast as you can. You can even skip the Protected mode and jump directly to Long mode
    

I went on and wrote my hobby OS on x86_64 too. Unfortunately, working in
x86_64 long mode is a little bit more difficult than using 32 bit protected
mode. You can go direct to long mode, but you'll have to write that from
scratch. GRUB and other multiboot protocol capable bootloaders set up 32-bit
protected mode for you but not long mode. You cannot be in long mode without
paging enabled (unlike in protected mode).

So if you want to "skip" protected mode, you'll have to write a pile of
assembly code to get there. x86_64 is a lot more work than 32bit x86.

    
    
      > Jump to C as soon as possible
    

This is most definitely the right thing to do. Jump into C code as soon as
possible. Getting shit done in Assembly is so much slower.

You only need a few pieces of assembly code to get an operating system
running: the boot code and the interrupt handler code. The boot code and the
interrupt handler are just small trampolines that go to C code as soon as
possible.

In addition to the boot and interrupt handler code, you occasionally need to
use some privileged mode CPU instructions (disable interrupts or change page
table, etc). Use inline assembler for that.

Anyone who (in this thread) suggested using something else than C seemed to be
fairly clueless about it. Of the choices you have available, C is the simplest
way to go. Everything else is either more work or more difficult.

    
    
      > Forget old interfaces like PCI, IDE, PS/2, Serial/Parallel ports.
    

Not so fast. You most likely want to implement a serial console for your
operating system. Maybe even add a serial port debugging interface (GDB
stubs).

You're most likely going to have to deal with PCI bus at some point too,
although many devices don't use the physical pci buses on motherboards, some
devices still hook up to the pci bus. Look at the output of "lspci" on Linux,
all of those devices are accessed through PCI. This includes USB, PCIe, SATA,
IDE, Network interfaces, etc.

Again, using the modern buses is a lot more work than using the old ones and
it partially builds upon the old things.

    
    
      > Why does every tutorial still use such an ancient device as Floppy?
    

Because when doing a bootloader from scratch for a tutorial, it's a lot easier
to use the floppy disk than it is to use a real hard disk or any other media.

    
    
      > Avoid the use of GRUB or any other multiboot bootloader – make my own and allow only my own OS on the system
    

No no no. If you want to build an operating system, do not build a bootloader.
Use the multiboot protocol and things will be a lot easier. You'll get started
so much faster and get to the real stuff sooner. (NOTE: I don't know how UEFI
devices boot, it might contain something like multiboot).

Most hobby operating systems are just half-assed stage 1 bootloaders. Just get
over the fact that you'll have to use code written by others and get booted.

Popular emulators (bochs, qemu) can boot multiboot kernels directly so you'll
save a lot of time there too.

You need to get booted in an emulator and running under a debugger as quickly
as possible. Operating system development is so much easier to do with a
debugger at hand. Failures generally cause a boot loop or hang the device so
there won't be a lot of diagnostics to help with issues.

So my advice is: set up Qemu + GDB + multiboot, and get your kernel booted in
a debugger as early as you can.

I won't go into commenting his wacky ideas about VFS structure or APIs. It's
nice to make great plans up front but by the time you're booted to your own
kernel, a lot of the naïve ideas you started with will be "corrected".

Happy hacking and do not listen to the naysayers.

PS. here's my hobby OS: <http://github.com/rikusalminen/danjeros>

------
dindresto
OS development can be fun. I'm writing a hobby OS myself, but currently using
GRUB. GDT and interrupts are working, so I can already e.g. get keyboard
input. But there's nothing like usermode programs yet. I'm 16, so what
bcantrill said might be true ("there is a certain arrogance of youth here").

------
capkutay
I would avoid the project unless you truly understand the scope of what you're
doing and are dying to get your hands dirty with vm and filesys implementation
despite little reward (other than the satisfaction of learning). OS dev is
quite low level and infamously hard to debug

------
grundprinzip
Good luck and thumbs up for the idea of writing a new OS. I think an
inspiration would be to look at BareMetal OS, perhaps you can find some ideas
there.

<http://www.returninfinity.com/baremetal.html>

------
ww520
Sigh. I don't know what to say. I admire OP's desire to dive into OS
development but I hope he has the perseverance to carry it through, because he
has a long way to fill in the huge gaps in his knowledge to build an OS.

------
dysoco
I like the idea of the directory tree, good luck! I have been interested in OS
Development lately, I have read some of the James tutorial, the OsDev Wiki,
and the Tanenbaum's book... but still have no idea what I'm doing.

------
capkutay
I would look at the Design of Unix. That's what Linus used to make Linux.
Individually study everything you don't understand...

Also, prepare for about 6 months of hard yet rewarding, given that you put in
about 50 hours a week ;)

------
DannyBee
Today's modern interfaces are tomorrow's obsolete ones. It's not like PCIe
will last any longer than PCI, PCI-X, ISA, Vesa Local Bus, EISA, etc.

~~~
zanny
I don't see why we aren't nearing a threshold where we can do all system
interconnects over some specificed serial digital interface and a parallel
one. Past a point, it becomes more logical than trying to optimize edge case
performants of things (like how dvi is uni-directional raw video digraphs) you
can just have some usb-like (but not usb, usb is ugly and tacky and a mess)
digital connector for every peripheral from the monitor to the network adapter
to the speakers, maybe even off one controller with software handling the
handshakes to determine what everything is connected to.

And then get rid of sata/pci/sas etc internal connectors and just use the same
interconnect hub as the external devices. Again, handshakes to determine
device connectivity.

Wouldn't that be so _easy_? One connection to rule them all! I'm not trying to
say it would be easy to get to, we are mired in a world where we look at a
concept like this and say "how dumb, you aren't utilizing a bidirectional link
with video feeds, or you aren't using the power connectivity to a network
router, or stream based vs packet based trasport layers having speed /
bandwidth advantages over one or the other. But wouldn't it be great to plug a
new gpu into a real universal serial bus?

------
emeidi
I remember a guy saying the same a few years ago ... what's his name? Linus?

------
djhworld
This is cool. Big project for one person, but cool none the less

------
monochromatic
Write your own OS: great!

Say you're writing your own OS: ok, sure...

------
christina_b
Good lord ...

------
ommunist
Read books, Guncha! Good luck. If Stallman did that, so can you.

------
drivebyacct2
[deleted] ChuckMcM is right, let him find out what he doesn't know. Props for
the ambition.

------
frozenport
3rd Year ECE + Hope . How did this make HN?

------
aeip
*Houston

~~~
theyshookhands
*whether

~~~
anonymouz
*useful

