Re: [Help-HURD] libdiskfs

[Marcus Brinkmann]

On Sun, May 18, 2003 at 09:28:41PM +0200, Monge Maurizio wrote:
> Where can get info about how do diskfs/pager/store work?

There is not much info about it available.  Some old postings in the list
should be helpful.  You should ask specific questions.

A store is a block device abstraction.  It's interface should be quite
clear.  store reads/writes are slow, because they access the disk.

Thus there is caching, provided by libpager.  We use Mach external memory
objects and Mach VM for this.  There is some info in the Mach manuals and
info pages about this.  Also, file mappings are implemented using libpager.

diskfs itself is callback based.  You implement the callbacks it expects you
to implement, providing the filesystem operations.  For this you need to
know about the node concept, inodes, iousers etc.  Studying the examples is
the most important thing to do here.

> Anyway it seems simpler, since linux fs drivers do register functions like
> open/write/read/readlink/..., and there is no implicit pager library.

Yeah, well, it works differently.  For example, the Linux code is not
multi-threaded.  Some things are easier in Linux, some in the Hurd.

Thanks,
Marcus

-- 
`Rhubarb is no Egyptian god.' GNU      http://www.gnu.org    marcus@gnu.org
Marcus Brinkmann              The Hurd http://www.gnu.org/software/hurd/
Marcus.Brinkmann@ruhr-uni-bochum.de
http://www.marcus-brinkmann.de/