Re: What is the volume driver?

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Mark,

Actually I consider the volume device layer the bottom of the 'upper
storage stack' while disk is the top of the 'lower storage stack'.

In fact, Disk.sys is not at the top of its stack - as far as
DEVICE_OBJECTs that represent disks themselves are concerned, they are
below the ones created by PartMgr.sys, on their stacks. The story with
partitions is quite different. DEVICE_OBJECTs that represent partitions
are created by Disk.sys and don't get attached to anything, so that you
can think of them as of PDOs. However, nothing gets attached to them -
instead, Ftdisk. sys communicates with Disk.sys via the private
interface, so that they are not on any stack.


If you want to make a distinction between disk and volume management, I
think it would be better to refer to these stacks with the terms
"physical" and "logical", rather than "lower" and "upper" - disks are
managed by the former, volumes are managed by the latter, and
partitions are the "missing link" between these two


Anton Bassov

Mark Roddy wrote:
On 18 Nov 2006 15:09:57 -0800, soviet_bloke@xxxxxxxxxxx wrote:

From the system's perspective, files are located not on hard disks but
on their partitions.
Physical partitions on hard disks, as well as on USB storage, are
managed by Disk.sys.
Unlike partitions, volumes are logical, so that they are just mounted
on physical partitions.
Logical volumes that correspond to physical partitions of basic disks
are managed by Ftdisk.sys (when it comes to the removable media, you
cannot mount logical volumes on it, so that Ftdisk.sys is out of play).
Ftdisk. sys communicates with Disk.sys via the private interface, so
that Ftdisk.sys is technically not a part of the storage stack.



Actually I consider the volume device layer the bottom of the 'upper
storage stack' while disk is the top of the 'lower storage stack'.



Anton Bassov



Balls wrote:
Hello,
I am looking for the volume (disk volume) driver that is responsible
for the volumes, i.e. C:\ or D:\ etc etc. Do I get an IRP
IRP_MJ_READ when I access a file on D:\ or E:\.
p.s.
I hope I am understanding the disk correctly, if not, please explain
what the difference between volume and disk driver.
Balls.


=====================
Mark Roddy DDK MVP
Windows Vista/2003/XP Consulting
Device and Filesystem Drivers
Broken Driver Code? Call us.
Hollis Technology Solutions 603-321-1032
www.hollistech.com

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