Writing a (BSD like) Operating Systems From Scratch

Fri May 24 16:58:09 UTC 2013

Hi Julian

 Thanks, any response is appreciated, here's mine:

> -----Original Message-----
> From: owner-freebsd-hackers at freebsd.org [mailto:owner-freebsd-
> hackers at freebsd.org] On Behalf Of Julian H. Stacey
> Sent: 24 May 2013 15:39
> To: Welcome, Traiano
> Cc: freebsd-hackers at freebsd.org
> Subject: Re: Writing a (BSD like) Operating Systems From Scratch
> 
> "Welcome, Traiano" wrote:
> > Hi All
> > I've been read thousands of pages of FreeBSD and Linux Kernel source
> code and books on the internals of BSD and Linux over the years in attempt
> to develop a complete understanding of operating systems (or at least, UNIX
> like ones). However, I feel that I'm as mystified as to the finer details as
> when I first started. So I've concluded that the best way to really understand
> the deep dark details of UNIX is to try and write one from scratch (using the
> general guidelines of standards like POSIX etc ...), and maybe taking a peek at
> BSD and Linux from time to time. My questions around this are:
> 
> Sorry, but your questions & text (see mega line above, no folds ! Ugh) tell me
> 
> 	A) You dont know enough, & would be better working with an
> existing
> 	   project, be it a BSD Linux Minix Sprite Mach whatever. Maybe
> 	   also doing some formal training in OSs eg a Uni. degree
> 	   in computing or whatever.

Right on the mark, Julian! The don't know enough part especially, hence the _questions_ (Normally asked by people who don't know enough).
May I ask where you get the divine wisdom to know  where I "would be better working with" ? don't you think that would be best left up to me?
So what if formal training in OSes is not an option to me ? Not all of us have the wealth and time, nor privilege of coming from a family that can 
afford such an education, like myself for example. What do you recommend for those of us who have neither the wealth nor luxury of time to pursue
" a Uni. degree  in computing or whatever." ?

You appear not to realize that to even begin working with one of the existing projects, you'd best have a solid understanding of OSes to begin with, 
which brings up an interesting catch -22 that goes something like:

 "You can't join the club, because you don't know enough. You can't know enough 'till you join our club". 

Is that the case or am I mistaken ?

> 
> 	B) You havent realised technology is moving faster & with ever more
> 	   more people working on OSs & tools, its like looking in
> 	   from the edge of an exploding galaxy & trying to understand
> 	   all within: by the time you do, its grown !
> 

May I ask how you jumped to that conclusion? What makes you think I want to keep at the cutting edge of everything? 
All I want to begin at the very basis and build up from there at my own pace, until I'm capable of building something very 
Basic, functional and something I can use to illustrate to myself the design principles involved in building operating systems.

> 	C) If people devoted tons of time over years to help you along,
> 	   it would be their & your time wasted to achieve anothernice
> 	   OS time that would be better spent if you & they worked
> 	   together on improving an existing OS - see (A) above.

Where did you get the idea that I'm asking for tons of time over years ? Have you a record of me going around the internet pestering people for answers on how to build operating systems? All I asked for was a couple of links and pointers, maybe a good book or two.  Besides, I'd be of no using helping to build spacecraft if I can barely build a cart, so no, my time would not be better spent helping people who really have a clue to improve existing OSes.

> Sorry it's not what you want to hear but modern OS are too big for
> 1 man, & evolving too fast, even those called Jollitz Tannenbaum or Linus, got
> replaced/ supplemented by Teams. Choose a project team & an aspect/
> technology within the team, & that will be useful not a waste of time.

I don't accept the conjecture that modern OSes are too big for one man. Modern OSes and their associated entourage of userpace and plugin modules maybe, but not the basic kernel/supervisor program. An OS is as big or small as you make it. I would like to eat this particular elephant one bite at a time. 

> 	Some OS's http://berklix.com/free/
> 

Thanks, nice link :-)

> Cheers,
> Julian
> --
> Julian Stacey, BSD Unix Linux C Sys Eng Consultant, Munich
> http://berklix.com  Reply below not above, like a play script.  Indent old text
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