devf-generic - what is it

Hi all,

I’m pretty much lame with QNX - sorry…

I’m using a 206MHz PPC405 based board with qnx 6.2 and the flash is accessed trough the generic fs
(devf-generic). So my question is:

Is it a compressed filesystem?
Is it a journaling fs?
If yes - how heavy is the CPU load for compression/joyrnaling?
Can this be a performance problem on the 206MHz power pc?
Where can I find some more detailed info on the qnx and flash filesystems coming with the neutrino
kernel?

Best Regards,

Alexander Popov ProSyst Bulgaria Inc.
Team Leader 48 Vladajska Str.
Dept: Real Time OS and Java VM Sofia 1606, Bulgaria
Phone: +359 2 952 35 81/203 http://www.prosyst.com
Mobile: +359 87 663 193 OSGi Technology Leaders

Alexander Popov <s_popov@prosyst.bg> wrote:

Hi all,

I’m pretty much lame with QNX - sorry…

I’m using a 206MHz PPC405 based board with qnx 6.2 and the
flash is accessed trough the generic fs
(devf-generic). So my question is:

Is it a compressed filesystem?

Yes and no. Compressed files will be transparently de-compressed,
but compression won’t be done on writes.

Is it a journaling fs?

No.

If yes - how heavy is the CPU load for compression/joyrnaling?

No load for journalling. No load for compression (not done).
Decompression is relatively cheap.

Can this be a performance problem on the 206MHz power pc?

Generally not an issue.

Where can I find some more detailed info on the qnx and flash
filesystems coming with the neutrino kernel?

QNX (online) documentation – System Architecture guide is a good place
to start on QNX overall.

-David

QNX Training Services
http://www.qnx.com/support/training/
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