From: Blocking paging I/O IRP’s
My FSF application defers file reads to a server user mode application,
which reads data, decrypts it, and passes it back to my driver
which in turn
passes it to the application that issued the file read request.
Is there some advantage using this design against issuing the reads
directly from filter code (via ZwReadFile) and process the data there?
Do I miss something?
Radek Liba
You are currently subscribed to ntfsd as: $subst(‘Recip.EmailAddr’)
To unsubscribe send a blank email to leave-ntfsd-$subst(‘Recip.MemberIDChar’)@lists.osr.com
Some people believe that it is a good idea to keep as much code out of the
kernel as possible. In theory, this increases the reliability of the
system. However, unprivileged code which is depended upon by privileged
code tends to take on the characteristics of privileged code. As a result,
the net reliability of the system does not always improve when code is moved
from supervisor mode to user mode.
-----Original Message-----
From: Radek Liba [mailto:xxxxx@tecomac.de]
Sent: Monday, February 05, 2001 4:58 AM
To: File Systems Developers
Subject: [ntfsd] server user mode application?
From: Blocking paging I/O IRP’s
> My FSF application defers file reads to a server user mode
application,
> which reads data, decrypts it, and passes it back to my driver
> which in turn
> passes it to the application that issued the file read request.
Is there some advantage using this design against issuing the reads
directly from filter code (via ZwReadFile) and process the data there?
Do I miss something?
Radek Liba
You are currently subscribed to ntfsd as: xxxxx@nsisw.com
To unsubscribe send a blank email to leave-ntfsd-$subst(‘Recip.MemberIDChar’)@lists.osr.com
You are currently subscribed to ntfsd as: $subst(‘Recip.EmailAddr’)
To unsubscribe send a blank email to leave-ntfsd-$subst(‘Recip.MemberIDChar’)@lists.osr.com
Bad code is bad code, supervisor or app. space. Problem is that bad code in R0
tends to be fatal and not “Application not responding.”
-Jack
Rob Fuller wrote:
Some people believe that it is a good idea to keep as much code out of the
kernel as possible. In theory, this increases the reliability of the
system. However, unprivileged code which is depended upon by privileged
code tends to take on the characteristics of privileged code. As a result,
the net reliability of the system does not always improve when code is moved
from supervisor mode to user mode.
> -----Original Message-----
> From: Radek Liba [mailto:xxxxx@tecomac.de]
> Sent: Monday, February 05, 2001 4:58 AM
> To: File Systems Developers
> Subject: [ntfsd] server user mode application?
>
>
> From: Blocking paging I/O IRP’s
> > My FSF application defers file reads to a server user mode
> application,
> > which reads data, decrypts it, and passes it back to my driver
> > which in turn
> > passes it to the application that issued the file read request.
>
> Is there some advantage using this design against issuing the reads
> directly from filter code (via ZwReadFile) and process the data there?
> Do I miss something?
>
> Radek Liba
>
> —
> You are currently subscribed to ntfsd as: xxxxx@nsisw.com
> To unsubscribe send a blank email to leave-ntfsd-$subst(‘Recip.MemberIDChar’)@lists.osr.com
>
You are currently subscribed to ntfsd as: xxxxx@r0r3.com
To unsubscribe send a blank email to leave-ntfsd-$subst(‘Recip.MemberIDChar’)@lists.osr.com
You are currently subscribed to ntfsd as: $subst(‘Recip.EmailAddr’)
To unsubscribe send a blank email to leave-ntfsd-$subst(‘Recip.MemberIDChar’)@lists.osr.com
The advantage is that all the reading, decompression, decryption or whatever
yo have to do is done in user mode. This means:
1- Much easier debugging.
2- You can use user mode code you already have with no modifications.
3- You can use C++ exceptions.
The cost is obviously some headaches besides the fact that you have to
implement a proper communication mechanism between the driver and the server
process.
-IGP-
-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com]On Behalf Of Radek Liba
Sent: lunes, 05 de febrero de 2001 10:58
To: File Systems Developers
Subject: [ntfsd] server user mode application?
From: Blocking paging I/O IRP’s
> My FSF application defers file reads to a server user mode application,
> which reads data, decrypts it, and passes it back to my driver
> which in turn
> passes it to the application that issued the file read request.
Is there some advantage using this design against issuing the reads
directly from filter code (via ZwReadFile) and process the data there?
Do I miss something?
Radek Liba
You are currently subscribed to ntfsd as: xxxxx@trymedia.com
To unsubscribe send a blank email to leave-ntfsd-$subst(‘Recip.MemberIDChar’)@lists.osr.com
You are currently subscribed to ntfsd as: $subst(‘Recip.EmailAddr’)
To unsubscribe send a blank email to leave-ntfsd-$subst(‘Recip.MemberIDChar’)@lists.osr.com
> The advantage is that all the reading, decompression, decryption or
whatever
yo have to do is done in user mode. This means:
1- Much easier debugging.
Debug the compression/encryption in user mode, then port to kernel mode.
Max
You are currently subscribed to ntfsd as: $subst(‘Recip.EmailAddr’)
To unsubscribe send a blank email to leave-ntfsd-$subst(‘Recip.MemberIDChar’)@lists.osr.com
> > The advantage is that all the reading, decompression, decryption or
whatever
> yo have to do is done in user mode. This means:
>
> 1- Much easier debugging.
Debug the compression/encryption in user mode, then port to kernel mode.
That would be great if the compression/encryption engine was not written in
C++ with heavy use of exceptions, for which, as far as I know, there is no
support in kernel mode…
-IGP-
You are currently subscribed to ntfsd as: $subst(‘Recip.EmailAddr’)
To unsubscribe send a blank email to leave-ntfsd-$subst(‘Recip.MemberIDChar’)@lists.osr.com
If you are referring to try/finally and try/except blocks they are
indeed supported in the kernel. If you look at the fastfat source in
the IFSKit you will see that it is used extensively.
Neal Christiansen
-----Original Message-----
From: Ignacio Garcia-Perez [mailto:xxxxx@trymedia.com]
Sent: Thursday, February 08, 2001 12:42 AM
To: File Systems Developers
Subject: [ntfsd] RE: server user mode application?
> The advantage is that all the reading, decompression, decryption or
whatever
> yo have to do is done in user mode. This means:
>
> 1- Much easier debugging.
Debug the compression/encryption in user mode, then port to kernel
mode.
That would be great if the compression/encryption engine was not written
in
C++ with heavy use of exceptions, for which, as far as I know, there is
no
support in kernel mode…
-IGP-
You are currently subscribed to ntfsd as: xxxxx@Exchange.Microsoft.com
To unsubscribe send a blank email to leave-ntfsd-$subst(‘Recip.MemberIDChar’)@lists.osr.com
You are currently subscribed to ntfsd as: $subst(‘Recip.EmailAddr’)
To unsubscribe send a blank email to leave-ntfsd-$subst(‘Recip.MemberIDChar’)@lists.osr.com
Hi, Neal:
If you are referring to try/finally and try/except blocks they are
indeed supported in the kernel. If you look at the fastfat source in
the IFSKit you will see that it is used extensively.
I was referring to the standard C++ exception mechanism. I must reuse code
that makes extensive use of C++ exceptions for error handling and don’t have
the time to convert and test it.
Regards. Nacho.
You are currently subscribed to ntfsd as: $subst(‘Recip.EmailAddr’)
To unsubscribe send a blank email to leave-ntfsd-$subst(‘Recip.MemberIDChar’)@lists.osr.com