[9fans] simplest disk filesystem

[9fans] simplest disk filesystem

[Yoann Padioleau]

Hi,

What is the simplest storage filesystem in terms of code size in plan9?
I’m looking for a very simple in-kernel filesystem. Maybe older version of plan9
was including such a filesystem? On Linux for instance the minixfs was probably
the simplest filesystem. The dos must also be simple but it’s currently a fileserver
which makes it sligtly more complicated.

Re: [9fans] simplest disk filesystem

[andrey mirtchovski]

/sys/src/cmd/ramfs.c?

On Tue, Jul 15, 2014 at 11:53 AM, Yoann Padioleau <pad@fb.com> wrote:
> Hi,
>
> What is the simplest storage filesystem in terms of code size in plan9?
> I’m looking for a very simple in-kernel filesystem. Maybe older version of plan9
> was including such a filesystem? On Linux for instance the minixfs was probably
> the simplest filesystem. The dos must also be simple but it’s currently a fileserver
> which makes it sligtly more complicated.

Re: [9fans] simplest disk filesystem

[Yoann Padioleau]

But I would like something that actually can persist … a real but simple storage
persistent filesystem.

On Jul 15, 2014, at 10:57 AM, andrey mirtchovski <mirtchovski@gmail.com> wrote:

> /sys/src/cmd/ramfs.c?
> 
> On Tue, Jul 15, 2014 at 11:53 AM, Yoann Padioleau <pad@fb.com> wrote:
>> Hi,
>> 
>> What is the simplest storage filesystem in terms of code size in plan9?
>> I’m looking for a very simple in-kernel filesystem. Maybe older version of plan9
>> was including such a filesystem? On Linux for instance the minixfs was probably
>> the simplest filesystem. The dos must also be simple but it’s currently a fileserver
>> which makes it sligtly more complicated.
> 

Re: [9fans] simplest disk filesystem

[Lee Fallat]

I don't know anything about ramfs but maybe you can modify it to read
all disk from storage then write back when done? Sounds really
inefficient though. Maybe if it was done with system files it'd be
more practical. AFAIK, but a bit off topic, DamnSmallLinux can do
this. Maybe you'd like to check that out.

On Tue, Jul 15, 2014 at 2:05 PM, Yoann Padioleau <pad@fb.com> wrote:
> But I would like something that actually can persist … a real but simple storage
> persistent filesystem.
>
> On Jul 15, 2014, at 10:57 AM, andrey mirtchovski <mirtchovski@gmail.com> wrote:
>
>> /sys/src/cmd/ramfs.c?
>>
>> On Tue, Jul 15, 2014 at 11:53 AM, Yoann Padioleau <pad@fb.com> wrote:
>>> Hi,
>>>
>>> What is the simplest storage filesystem in terms of code size in plan9?
>>> I’m looking for a very simple in-kernel filesystem. Maybe older version of plan9
>>> was including such a filesystem? On Linux for instance the minixfs was probably
>>> the simplest filesystem. The dos must also be simple but it’s currently a fileserver
>>> which makes it sligtly more complicated.
>>
>
>

Re: [9fans] simplest disk filesystem

[David du Colombier]

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You van take a look to paqfs(4) (read-only) or flashfs(4).

--
David du Colombier

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Re: [9fans] simplest disk filesystem

[erik quanstrom]

On Tue Jul 15 13:59:15 EDT 2014, mirtchovski@gmail.com wrote:
> /sys/src/cmd/ramfs.c?
> 
> On Tue, Jul 15, 2014 at 11:53 AM, Yoann Padioleau <pad@fb.com> wrote:
> > Hi,
> >
> > What is the simplest storage filesystem in terms of code size in plan9?
> > I’m looking for a very simple in-kernel filesystem. Maybe older version of plan9
> > was including such a filesystem? On Linux for instance the minixfs was probably
> > the simplest filesystem. The dos must also be simple but it’s currently a fileserver
> > which makes it sligtly more complicated.

ramfs doesn't count by the op's rules, since it's not in kernel.
(and i think the op didn't think to specify that it store to disk.)
in fact there aren't any in-kernel file storage file systems in plan 9.
unless you count ken's file server, which is not really in kernel, it
IS the kernel.  it also isn't on the same box as a kernel you're talking
about.

the simplist file on disk is likely fat, followed by kfs.  simple
sadly is not a synonym for nice.  :-)

- erik

Re: [9fans] simplest disk filesystem

[Brian L. Stuart]

> I’m looking for a very simple in-kernel filesystem.

What's motivating the desire for to be in-kernel?  Nearly,
every file system in Plan 9 runs in user space.  All the
ones that have been mentioned do.  The only in-kernel
file system in the labs' distribution is devroot which is
read-only and intended only to provide enough bits to
get the system up and running.  9atom also includes
a devtinyfs that you could take a look at.

BLS

Re: [9fans] simplest disk filesystem

[Yoann Padioleau]

I’m trying to make a tutorial explaining the code of a not too large kernel
(9), but there are too many things to explain so I have to cut things.
So having a simple fs which does not require to explain
9p, the rpc, the mount device, etc would be great.
I know that explaining plan9 without 9p is kinda nonsense, but I would
do that in another tutorial.

On Jul 15, 2014, at 1:52 PM, Brian L. Stuart <blstuart@bellsouth.net> wrote:

>> I’m looking for a very simple in-kernel filesystem.
> 
> What's motivating the desire for to be in-kernel?  Nearly,
> every file system in Plan 9 runs in user space.  All the
> ones that have been mentioned do.  The only in-kernel
> file system in the labs' distribution is devroot which is
> read-only and intended only to provide enough bits to
> get the system up and running.  9atom also includes
> a devtinyfs that you could take a look at.
> 
> BLS
> 
> 

Re: [9fans] simplest disk filesystem

[Brian L. Stuart]

> I’m trying to make a tutorial explaining the code of
> a not too large kernel (9), but there are too many
> things to explain so I have to cut things.  So having
> a simple fs which does not require to explain 9p, the
> rpc, the mount device, etc would be great.

In that case, I'd suggest using devroot since it's useful
to know how things get bootstrapped and having a
small set of files in the kernel image is a handy technique
for embedded applications.  Although it doesn't talk to
any disk devices, you can point to the next tutorial and
explain that most file systems run as user applications
and communicate with the disks by way of 9p.

BLS

Re: [9fans] simplest disk filesystem

[Kurt H Maier]

Quoting Yoann Padioleau <pad@fb.com>:

> I’m trying to make a tutorial explaining the code of a not too large kernel
> (9), but there are too many things to explain so I have to cut things.
> So having a simple fs which does not require to explain
> 9p, the rpc, the mount device, etc would be great.
> I know that explaining plan9 without 9p is kinda nonsense, but I would
> do that in another tutorial.

What is the motivation of choosing a distributed OS without wanting to
explain how distributed operating systems work?

khm

Re: [9fans] simplest disk filesystem

[erik quanstrom]

> What is the motivation of choosing a distributed OS without wanting to
> explain how distributed operating systems work?

the standard definition of distributed os rather excludes plan 9.

- erik

Re: [9fans] simplest disk filesystem

[Kurt H Maier]

Quoting erik quanstrom <quanstro@quanstro.net>:

>> What is the motivation of choosing a distributed OS without wanting to
>> explain how distributed operating systems work?
>
> the standard definition of distributed os rather excludes plan 9.
>
> - erik

Please document this standard, including which standards body ratified it.

khm

Re: [9fans] simplest disk filesystem

[sl]

It just seems like creating a fake os (as in, no one even intends
to use this os) from scratch in order to explain a real os (as in,
the goal is to finally understand or at least use this os) makes
things even more difficult to understand.

sl

Re: [9fans] simplest disk filesystem

[Yoann Padioleau]

Yes, maybe you’re right :) I’ll probably stick to the idea on just focus on 
devroot.c as someone suggested.

On Jul 16, 2014, at 11:17 AM, sl@9front.org wrote:

> It just seems like creating a fake os (as in, no one even intends
> to use this os) from scratch in order to explain a real os (as in,
> the goal is to finally understand or at least use this os) makes
> things even more difficult to understand.
> 
> sl
>