RE: [ros-dev] A new sub-project

[Waldo Alvarez Cañizares]

Hi:
>  It is true that a filesystem that has a usermode
> component
> can not be used as a boot driver 
I beleive this is not true. There are operating systems (at least I could name one) with
all the drivers running in user mode leaving only a minimal kernel. Is sort of a
client-server model, and yes with protection for file/folders. Now the ROS boot loader
first loads kernel-hal-fat driver-... It has to, otherwise how would you load the
filesystem driver? Now switching  ring 0 <-> ring 3 with that in RAM... If you also
load ntdll that way. Hmmm Why not? I beleive that is enought to read/write something to
disk.
Regards
Waldo

[Joseph Galbraith]

Waldo Alvarez Cañizares wrote:
>   Hi:
> >  It is true that a filesystem that has a usermode
> > component
> > can not be used as a boot driver 
>  I beleive this is not true. There are operating systems (at
>  least I could name one) with all the drivers running in
>  user mode leaving only a minimal kernel. Is sort of a
>  client-server model, and yes with protection for file/folders.
>  Now the ROS boot loader first loads kernel-hal-fat driver-... It
>  has to, otherwise how would you load the filesystem driver? Now
>  switching  ring 0 <-> ring 3 with that in RAM... If you also load
>  ntdll that way. Hmmm Why not? I beleive that is enought to read/write
>  something to disk. 
Hmmm... maybe I misspoke and wasn't clear.
What I meant to say was that a filesystem that
requires a user-mode component can not be the
boot filesystem.
Thanks,
Joseph

[Oliver Schneider]

>   What I meant to say was that a filesystem that
>  requires a user-mode component can not be the
>  boot filesystem. 
I agree with you. The problem with the filesystem proposed in the
recent
mail is that it depends on a _secondary_ and tertiary usermode component -
which itself requires the FS to be loaded already. Maybe it would be
possible to have a monolithic usermode (DB) FS-driver booting the system if
the loader boots like -> kernel + hal + usermode-FS.
However, the "DB filesystem" described so far would require:
-> kernel + hal + Usermode[MySQL + Tcl + ... + FS].
How can you load MySQL and Tcl without the (whatever-mode) FS?
Consequence: it's not bootable! (okay, maybe coLinux could run there ;-)
Just my two cents,
Oliver
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