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[[!meta copyright="Copyright © 2012 Free Software Foundation, Inc."]]
[[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable
id="license" text="Permission is granted to copy, distribute and/or modify this
document under the terms of the GNU Free Documentation License, Version 1.2 or
any later version published by the Free Software Foundation; with no Invariant
Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license
is included in the section entitled [[GNU Free Documentation
License|/fdl]]."]]"""]]
# IRC, freenode, #hurd, 2012-07-19
<nowhere_man> well, I really actively started last week, so I'm ironing my
various use cases and above all I'm taking my barings in Hurd's code
<nowhere_man> I'm currently reading boot/ and pfinet/
<braunr> sorry for asking but
<braunr> can you describe brielfy what you mean to achieve
<braunr> i know it sounds weird but the project description is a bit vague
for me
<nowhere_man> OK
<nowhere_man> the main goal is to be able to easily spawn a subhurd that's
connected in some way to its host
<braunr> ok
<nowhere_man> mainly connected by network, possibly sharing resources like
FS
<braunr> is it similar in spirit with something like linux containers ?
<nowhere_man> IIRC about them, yes
<braunr> ok
<braunr> that will do for me then
<tschwinge> Yes, so not complete virtualization, but instaed limitied to
several components.
<braunr> lxc with more runtime features to increase/decrease the level of
isolation
<nowhere_man> at first it would be static, at creation time only
<braunr> ok, i clearly understand the proposal now :)
<braunr> what kind of help could you need in the near future ?
<braunr> (except permanent access to youpi's brain?)
<tschwinge> Yes, that's my question, too -- what can we do to "get this
thing going".
<nowhere_man> by monday or tuesday I should be clear on what I understand
or not in the code
<nowhere_man> I'm still a bit up to my elbows in it
<nowhere_man> at that point I'll be happy to be able to pop a lot of
questions about it
<braunr> so you'll be ready for the next meeting
<nowhere_man> yeah
<tschwinge> Please do as soon as there are questions that you cannot
resolve in a reasonably short amount of time.
<tschwinge> So often a quick hint from someone else already helps to ge
un-stuck.
<nowhere_man> OK
<tschwinge> There is no problem with asking for help given this huge and
convoluted code-base, where often design decisions are not obvious, too.
<nowhere_man> I will
<tschwinge> Good. :-)
<antrik> nowhere_man: hm... what you said so far doesn't sound any
different than the work zhengda already did on boot years ago...
<antrik> (although none of it ever got upstream IIRC :-( )
<nowhere_man> antrik: wasn't aware of it, is there some code published?
<tschwinge> There are bits and pieces, but certainly there is enough work
left to be done, to put it all together.
<antrik> yes, his git repository should be up somewhere. it's quite
convoluted though, as he worked on several things, and also wasn't very
experienced with revision control in the beginning
<tschwinge> nowhere_man:
http://www.gnu.org/software/hurd/community/gsoc/2008.html
<tschwinge> nowhere_man: http://www.gnu.org/software/hurd/user/zhengda.html
<tschwinge> Second section of the latter one.
<antrik> well, my understanding of the proposal (and more or less what I
was driving at in the project idea, which is rather vague admittedly) is
something lighter than a real subhurd... rather some kind of thin
subenvironment that doesn't actually boot a complete system instance with
various daemons etc.
<tschwinge> nowhere_man: It is certainly valid for you to use pre-existing
code/patches, by the way.
<antrik> BTW, regarding the "full subhurd" thing, the missing pieces are
mostly virtual device implementations
<antrik> (that and some tough bug(s) remaining in zhengda's modified
boot...)
<nowhere_man> cool, I'll take a look
<antrik> in any case, getting a picture of the work zhengda did is, is
definitely the first thing to do :-)
<tschwinge> nowhere_man: I'll also try to locate some bits and stuff from
his verious repositories (I just fond a Subverision one; will convert to
Git).
<antrik> tschwinge: I'm pretty sure zhengda's git repository was converted
from the SVN one...
<tschwinge> antrik: Thanks for reminding us about this -- I failed to
remember all that.
<antrik> (which was in turn converted from CVS...)
<tschwinge> antrik: OK, will have a lot.
<tschwinge> Yeah, found a CVS tree, too. ;-)
<antrik> BTW, zhengda's work more exactly was about subhurd without root
privileges. but that lays a lot of the groundwork for all kinds of more
flexible subhurd usage
<antrik> (but it's still quite a different thing that thing
subenvironments, so don't get confused...)
<antrik> err... thin subenvironments
# IRC, freenode, #hurd, 2012-07-27
<nowhere_man> bddebian: I'm actually not progressing much while reading the
source, I'm jumping all over the place to grasp the various types and
functions used where I start
<nowhere_man> would there be a few starting points that could help me?
<tschwinge> nowhere_man: So what exactly is your status; what are you
doing, what do you need help with? We surely can provide help, but need
to know where.
<nowhere_man> I'm starting from the source of boot/ and pfinet/ and as soon
as I encounter something that I don't understand, I find its definition
<nowhere_man> I'm kind of doing a depth-first search of what I need to
understand in the source code
<nowhere_man> I'm wondering if there are a few places in the source code
that I should start reading before anything else
<nowhere_man> well, I'll have to go in a few minutes
<nowhere_man> I'll continue my DFS ;-)
# IRC, freenode, #hurd, 2012-08-02
<nowhereman> well, I made a leap forward in understanding the code, when I
stopped my DFS
<nowhereman> in hindsight, I'd say my way of approaching the code was
probably one of the worst possible
<braunr> oh
<tschwinge> OK, so at least you learned something, which is good.
<tschwinge> So, what's the new approach? And what are you working on at
the moment
<tschwinge> ?
<nowhereman> I just remembered SICP, the idea of wishful thinking when you
code, and didn't bother with the fine details behind what I'm reading
<nowhereman> like, I don't really get what happens when a Mach port is
allocated, but I know approximately what a Mach port is
<tschwinge> So originally you worked on investigating all that, every line
of code?
<nowhereman> almost, yeah
<braunr> nowhereman: again, feel free to ask
<tschwinge> Yes indeed -- that's too complex for a single person to tackle
at one time.
<braunr> and quickly
<braunr> don't loose time
<tschwinge> Not even braunr and I have looked up all these things.
(Speaking for Richard here, but I'm quite sure he'll agree. Perhaps he
has in fact looked up all the Mach things, though.)
<tschwinge> nowhereman: ufc?
<nowhereman> BTW, last week I wanted to push my description of how the tool
could be used, the use cases
<nowhereman> ufs
<nowhereman> but flubber is not online
<tschwinge> nowhereman: Oh, why ufs specifically?
<braunr> don't waste time on ufs
<braunr> really
<tschwinge> nowhereman: Yes, flubber is down. But you can push directly to
the Savannah repository.
<tschwinge> nowhereman: Please immediatelly tell us if you're stuck on
something, like flubber not being available.
<tschwinge> We may not be able to help immediatelly, but we're the at least
aware of issues.
<braunr> and we may be able to help immediately :)
<tschwinge> As we're not sitting in a lab next to each other, we can't tell
otherwise what's going on.
<tschwinge> We may in fact even be able to tell you immediatelly to use
Savannah instead of flubber, indeed.
<tschwinge> nowhereman: So, back to ufs -- which you don't specifically
need to look at, I think -- ext2fs is what everyone uses. But even there
you shouldn't really need to know many details/internals.
<nowhereman> OK, I was looking into it has it appears in hurd.boot
<tschwinge> Ah, OK. Yeah, that's just an example/template, and should use
ext2fs nowadays.
<nowhereman> in fact, as far as FS are concerned, I suppose I will merely
need to know how to pass a port to the host's FS to some proxy FS in the
subhurd
<nowhereman> mmmh, Savannah only mentions a hurd.git
<tschwinge> Exactly that is the abstraction level you need, yes.
<nowhereman> I'm looking at http://savannah.gnu.org/git/?group=hurd
<tschwinge> Yeah, that's a known shortcoming -- look here instead:
http://git.savannah.gnu.org/cgit/hurd
<tschwinge> Here is some more up-to-date stuff on subhurds:
http://www.gnu.org/software/hurd/hurd/subhurd.html
<tschwinge> nowhereman: You know how to tell git to add a new remote to
your web pages checkout and such stuff?
<nowhereman> yeah, no problem with that
<braunr> have you prepared any question to ask us ?
<nowhereman> the only I have now is if you can tell me where to look in the
code about passing Mach ports
<braunr> you don't pass ports, you pass rights
<braunr> http://www.gnu.org/software/hurd/gnumach-doc/index.html is the
best location to have a look at
<braunr>
http://www.gnu.org/software/hurd/gnumach-doc/Exchanging-Port-Rights.html#Exchanging-Port-Rights
<braunr> i suppose the mig doc will help too, as you may be using a higher
level interface to exchange rights
<braunr> be careful about user references on port rights
<braunr> deallocate releases a reference, it doesn't immediately destroy a
resource
<braunr> portinfo -v can help monitoring a task's rights
<braunr> nowhereman: so what are you planning to do now ?
<braunr> during the next week
<nowhereman> documenting what I understand from the boot process and where
things can be changed to fit my various use cases
<braunr> do you expect that to take the whole week ?
<nowhereman> and doing some first modifications to servers for the simplest
cases
<braunr> ok
<braunr> well i hope you're able to really start working on it soon, and
won't face weird issues in the meantime
<braunr> i'm a bit disappointed that you don't have more questions
<braunr> my feeling is you either did understand everything (except passing
port rights), or you didn't attempt to seriously understand the code
<braunr> or you don't dare ask questions
<braunr> this is something that must change
<braunr> or these meetings won't be as useful as they could be
<tschwinge> Yes. But also please don't wait for the meetings, but ask
questions throughout the week, too.
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