[9fans] Which thing was harder for u to grasp relating Plan 9?

[9fans] Which thing was harder for u to grasp relating Plan 9?

[Francisco J Ballesteros]

I´m writing a book for the introductory course in OS at urjc, that
we teach using Plan 9. Most of it is a a lot of generic introductory
stuff about the system.

I´d love to know the top-10 of "hard-to-get" concepts about the system,
specially for new comers,
to try to cover them.

thanks a lot in any case.

Re: [9fans] Which thing was harder for u to grasp relating Plan 9?

[Rob Pike]

I would suggest: why Ken took so long to implement Datakit.

On a more serious note, John Lions never quite got his head
around the idea of a channel. If you come from Unix, I think
it's tricky; you're carrying too much baggage.

-rob

On 7/11/06, Francisco J Ballesteros <nemo@lsub.org> wrote:
> I´m writing a book for the introductory course in OS at urjc, that
> we teach using Plan 9. Most of it is a a lot of generic introductory
> stuff about the system.
>
> I´d love to know the top-10 of "hard-to-get" concepts about the system,
> specially for new comers,
> to try to cover them.
>
> thanks a lot in any case.
>

Re: [9fans] Which thing was harder for u to grasp relating Plan 9?

[Roman Shaposhnik]

On Tue, 2006-07-11 at 20:52 +0200, Francisco J Ballesteros wrote:
> I´m writing a book for the introductory course in OS at urjc, that
> we teach using Plan 9. Most of it is a a lot of generic introductory
> stuff about the system.
> 
> I´d love to know the top-10 of "hard-to-get" concepts about the system,
> specially for new comers,
> to try to cover them.

  If you mean implementation concepts, then my list would
definitely include:

   0. the fact that devmnt.c is just that -- another dev*
      and how it functions.
   1. waserror & co.
   2. devdraw and how it multiplex everything internally
      without much help from rio.

Thanks,
Roman.

Re: [9fans] Which thing was harder for u to grasp relating Plan 9?

[jmk]

On Tue Jul 11 14:55:53 EDT 2006, robpike@gmail.com wrote:
> I would suggest: why Ken took so long to implement Datakit.
> ...

There was a shortage of 'goto' statements at the time, we had
to wait for a new shipment.

Re: [9fans] Which thing was harder for u to grasp relating Plan 9?

[Sascha Retzki]

> On Tue, 2006-07-11 at 20:52 +0200, Francisco J Ballesteros wrote:
>
> I´d love to know the top-10 of "hard-to-get" concepts about the system,
> specially for new comers,
> to try to cover them.
> 

1.) private namespaces
2.) stop thinking in complex or overcomplicated patterns

Re: [9fans] Which thing was harder for u to grasp relating Plan 9?

[Corey]

On Tuesday 11 July 2006 13:18, Sascha Retzki wrote:
> > On Tue, 2006-07-11 at 20:52 +0200, Francisco J Ballesteros wrote:
> > I´d love to know the top-10 of "hard-to-get" concepts about the system,
> >
<snip>
> 2.) stop thinking in complex or overcomplicated patterns
> 

That's a good one, and more difficult than it may seem.

Re: [9fans] Which thing was harder for u to grasp relating Plan 9?

[Sascha Retzki]

>> 2.) stop thinking in complex or overcomplicated patterns
>>
>
> That's a good one, and more difficult than it may seem.

The funny thing is, the more I work on Wintendo or lunix, the more I forget about that thing.

Just give me my daily Plan9 and everything is ok ;)

Re: [9fans] Which thing was harder for u to grasp relating Plan 9?

[David Leimbach]

On 7/11/06, Francisco J Ballesteros <nemo@lsub.org> wrote:
> I´m writing a book for the introductory course in OS at urjc, that
> we teach using Plan 9. Most of it is a a lot of generic introductory
> stuff about the system.
>
> I´d love to know the top-10 of "hard-to-get" concepts about the system,
> specially for new comers,
> to try to cover them.
>
> thanks a lot in any case.
>

You might consider talking about filesystems and read/write as RPC
mechanisms.  I don't think people really got that or get that today.

Look at FreeBSD with it's blahctl programs for every device.  Having
the ability to talk to a mounted file for control simplifies a lot of
things.

Might want to compare such a concept to /proc on linux though I think
they even overcomplicated /proc there.  (see the miscellaneous binary
format support that's available)

A potentially good example about the power of the filesystem as a
control interface would probably be burning a CD in Plan 9.  That
could cover a lot of "neat stuff" like the 9660srv program.

I had fun playing with eia serial access and control myself at home too.

Also, there was my experience trying to add an option to Rio to deal
with the fact that I didn't like the labels I was getting for "rio in
rio" sessions.  Russ Cox straightened me out, and I got to throw away
some new C code I didn't really want to maintain anyway.

http://mordor.tip9ug.jp/who/leimy/session.html

That was a very enightening experience for me.  A lot more system
behavior could be changed through the filesystem and new applications
of things like /dev/null than I had actually imagined.  It was a real
brain-stretcher.  (not a gurney... that's linux).

Dave

Re: Re: [9fans] Which thing was harder for u to grasp relating Plan 9?

[Jack Johnson]

On 7/11/06, Sascha Retzki <sretzki@gmx.de> wrote:
> 1.) private namespaces

As perhaps the longest running newbie on the list, I would say this is
probably tops.  Though not hard to grasp, I found it tough to
practice.  I still occasionally find myself doing *nixisms like
mounting something in one window and expecting access in another.

-J

Re: Re: [9fans] Which thing was harder for u to grasp relating Plan 9?

[Francisco J Ballesteros]

Thanks for your answers.

Just to clarify. The book is about using the system, not about internals.
I see that my mail did say other thing, sic.
Our introductory course to SO teachs them how to use the system, this
includes programming. Using both the shell and most of the system calls.
The reason is that I found that they only really understand the concepts when
they use them. I'm trying to teach the concepts in a practical way.

Going back to my question about the top-10, I remember that it was very
hard to me to understand why
bind / /
was there after I did a
bind -b whatever /

Now it seems clear and very simple, but it was not at all for me initially.

I'll save all your comments for another book that I plan to write
after I finish the
one on programming and using the system. So, thanks again.

Re: Re: [9fans] Which thing was harder for u to grasp relating Plan 9?

[Richard Bilson]

On 7/12/06, Francisco J Ballesteros <nemo@lsub.org> wrote:
>
> Going back to my question about the top-10, I remember that it was very
> hard to me to understand why
> bind / /
> was there after I did a
> bind -b whatever /
>
> Now it seems clear and very simple, but it was not at all for me initially.

For me, the whole idea of "bind" confused me, because I expected more
from it -- I thought it would be more like a BSD-style union mount. It
took a while for me to realize that it's actually a much simpler
mechanism designed to solve a different problem.

Re: Re: [9fans] Which thing was harder for u to grasp relating Plan 9?

[Skip Tavakkolian]

> Going back to my question about the top-10, I remember that it was very
> hard to me to understand why
> bind / /
> was there after I did a
> bind -b whatever /

i saw brucee do a copy from his laptop (drawterm) to his cpu
via an intermediate cpu. something like:

cpu% cpu -h a
cpu% cp /mnt/term/mnt/term/something .

it's not hard to understand how it works, but i hadn't thought of
using anything like that.

Re: Re: [9fans] Which thing was harder for u to grasp relating Plan 9?

[csant]

> Just to clarify. The book is about using the system, not about internals.
Then (if not too silly a problem) my n00b issue (that I actually still
haven't completely worked out):

What mostly confuses me is how authentication works in Plan 9.

It seems quite straightforward to grasp its concepts, but obviously I am
missing something about the different roles needed in the authentication
process: the concrete problem being that I am trying to set up a
standalone desktop machine with authentication, and I get confused about
how to pack all different roles into one machine.

/c

Re: [9fans] Which thing was harder for u to grasp relating Plan 9?

[Ronald G Minnich]

csant wrote:
>> Just to clarify. The book is about using the system, not about internals.
>
> Then (if not too silly a problem) my n00b issue (that I actually still
> haven't completely worked out):
>
> What mostly confuses me is how authentication works in Plan 9.
>
> It seems quite straightforward to grasp its concepts, but obviously I
> am  missing something about the different roles needed in the
> authentication  process: the concrete problem being that I am trying to
> set up a  standalone desktop machine with authentication, and I get
> confused about  how to pack all different roles into one machine.


yep, this is it for me. I'm always screwing it up.

ron

Re: [9fans] Which thing was harder for u to grasp relating Plan 9?

[Russ Cox]

Authentication confuses me too.

Russ

Re: Re: [9fans] Which thing was harder for u to grasp relating Plan 9?

[andrey mirtchovski]

can you tell us why? you undoubtedly know it better than anyone, why
is it still confusing? is there something you'd like to see done
differently? is there a better way?

On 7/12/06, Russ Cox <rsc@swtch.com> wrote:
> Authentication confuses me too.
>
> Russ
>