Filter for RAID and File System

NTFSD
1

Thanks Max. Is there any document or book or URL that has details on these
issues. Our problem is to create a Software RAID, but we do not know where
to put a filter. Is it possible to put a filter over volume manager? How
does one set the registry to do that?

Regards,
Basudeb

Return-Path:
Delivered-To: xxxxx@giascl01.vsnl.net.in
From: “Maxim S. Shatskih”
To: “File Systems Developers”
Subject: [ntfsd] Re: SYMEVENT.SYS
Date: Fri, 15 Mar 2002 21:55:49 +0300
Organization: StorageCraft
At 09:55 PM 3/15/02 +0300, you wrote:
>> How does WIN2k come to know the partition information of a hard disk?
>
>The disk driver+ClassPnP combo read the MBR record by IoReadPartitionTable
(which parses the MBR) and then creates device objects
>for each partition as a PnP bus driver.
>The have “STORAGE\Partition” PnP ID. PartMgr is a filter for this ID.
>
>> What are the functions of IOCTL_DISK_GET_DRIVE_LAYOUT &
>> IOCTL_DISK_GET_PARTITION_INFO in this matter?
>
>These ones are serviced by the disk driver which keeps the partition table
in its memory.
>
>> Also, what is partmgr doing as a disk filter?
>
>PartMgr handles partition arrival-removal. The volume managers register
themselves in PartMgr. PartMgr’s job is to report partition
>arrival-removal to the volume managers.
>The default volume manager is FtDisk.sys - for simple partitions and for
legacy NT4 FtDisk volumes. DmIo (Dynamic Disk) is another
>volume manager.
>
>Volume manager is a place to implement any kinds of software RAID. It’s
primary purpose is to create a harddisk volume device object
>(this is NOT a partition or physical disk device object) and to handle IO
on it. On the upper end, it receives IRPs from the
>filesystems. On the lower one, it talks to partition device objects and
receive partition arrival-removal notification from PartMgr.
>
>Filesystems talk to volume manager’s device objects, not to Disk.sys ones.
>
>Both PartMgr and FtDisk are essential parts of the OS and are always loaded.
>
> Max
>
>
>
>—
>You are currently subscribed to ntfsd as: xxxxx@giascl01.vsnl.net.in
>To unsubscribe send a blank email to %%email.unsub%%
>
>

2

way to go about this issue is to write a parallel volume manager. There is
concept of PDO and FDOs.In a way the VMs are function driver as well as
pseudo bus drivers. Just like this you have disk driver. In this case, VM
acts as function driver for the hard partitions created on the disk and as
bus drivers for soft partitions created by VM. You would need to register
with Partition Manager for any arrival of new partitions as well as claiming
a partition.
On W2K, this isn’t a “really” filter driver. You would need to understand
how a bus driver and as well function driver. I think MS DDK does a good job
on that.
For understanding on how storage stack works on W2k, there are two piece
articles written by Mark Russinovich or you could refer to “Inside Windows
2000”.
http://www.winnetmag.com/Articles/Index.cfm?ArticleID=8127
http://www.winnetmag.com/Articles/Index.cfm?ArticleID=8303
I have not found any really good book on these issues.DDK is the best place.

-----Original Message-----
From: Basudeb [mailto:xxxxx@giascl01.vsnl.net.in]
Sent: Friday, March 15, 2002 7:30 PM
To: File Systems Developers
Subject: [ntfsd] Filter for RAID and File System

Thanks Max. Is there any document or book or URL that has details on these
issues. Our problem is to create a Software RAID, but we do not know where
to put a filter. Is it possible to put a filter over volume manager? How
does one set the registry to do that?

Regards,
Basudeb

Return-Path:
Delivered-To: xxxxx@giascl01.vsnl.net.in
From: “Maxim S. Shatskih”
To: “File Systems Developers”
Subject: [ntfsd] Re: SYMEVENT.SYS
Date: Fri, 15 Mar 2002 21:55:49 +0300
Organization: StorageCraft
At 09:55 PM 3/15/02 +0300, you wrote:
>> How does WIN2k come to know the partition information of a hard disk?
>
>The disk driver+ClassPnP combo read the MBR record by IoReadPartitionTable
(which parses the MBR) and then creates device objects
>for each partition as a PnP bus driver.
>The have “STORAGE\Partition” PnP ID. PartMgr is a filter for this ID.
>
>> What are the functions of IOCTL_DISK_GET_DRIVE_LAYOUT &
>> IOCTL_DISK_GET_PARTITION_INFO in this matter?
>
>These ones are serviced by the disk driver which keeps the partition table
in its memory.
>
>> Also, what is partmgr doing as a disk filter?
>
>PartMgr handles partition arrival-removal. The volume managers register
themselves in PartMgr. PartMgr’s job is to report partition
>arrival-removal to the volume managers.
>The default volume manager is FtDisk.sys - for simple partitions and for
legacy NT4 FtDisk volumes. DmIo (Dynamic Disk) is another
>volume manager.
>
>Volume manager is a place to implement any kinds of software RAID. It’s
primary purpose is to create a harddisk volume device object
>(this is NOT a partition or physical disk device object) and to handle IO
on it. On the upper end, it receives IRPs from the
>filesystems. On the lower one, it talks to partition device objects and
receive partition arrival-removal notification from PartMgr.
>
>Filesystems talk to volume manager’s device objects, not to Disk.sys ones.
>
>Both PartMgr and FtDisk are essential parts of the OS and are always
loaded.
>
> Max
>
>
>
>—
>You are currently subscribed to ntfsd as: xxxxx@giascl01.vsnl.net.in
>To unsubscribe send a blank email to %%email.unsub%%
>
>

—
You are currently subscribed to ntfsd as: xxxxx@Legato.COM
To unsubscribe send a blank email to %%email.unsub%%

3

You must write your own volume manager for this.

Max

----- Original Message -----
From: “Basudeb”
To: “File Systems Developers”
Sent: Saturday, March 16, 2002 6:29 AM
Subject: [ntfsd] Filter for RAID and File System

> Thanks Max. Is there any document or book or URL that has details on these
> issues. Our problem is to create a Software RAID, but we do not know where
> to put a filter. Is it possible to put a filter over volume manager? How
> does one set the registry to do that?
>
>
> Regards,
> Basudeb
>
>
>
>
> Return-Path:
> Delivered-To: xxxxx@giascl01.vsnl.net.in
> From: “Maxim S. Shatskih”
> To: “File Systems Developers”
> Subject: [ntfsd] Re: SYMEVENT.SYS
> Date: Fri, 15 Mar 2002 21:55:49 +0300
> Organization: StorageCraft
> At 09:55 PM 3/15/02 +0300, you wrote:
> >> How does WIN2k come to know the partition information of a hard disk?
> >
> >The disk driver+ClassPnP combo read the MBR record by IoReadPartitionTable
> (which parses the MBR) and then creates device objects
> >for each partition as a PnP bus driver.
> >The have “STORAGE\Partition” PnP ID. PartMgr is a filter for this ID.
> >
> >> What are the functions of IOCTL_DISK_GET_DRIVE_LAYOUT &
> >> IOCTL_DISK_GET_PARTITION_INFO in this matter?
> >
> >These ones are serviced by the disk driver which keeps the partition table
> in its memory.
> >
> >> Also, what is partmgr doing as a disk filter?
> >
> >PartMgr handles partition arrival-removal. The volume managers register
> themselves in PartMgr. PartMgr’s job is to report partition
> >arrival-removal to the volume managers.
> >The default volume manager is FtDisk.sys - for simple partitions and for
> legacy NT4 FtDisk volumes. DmIo (Dynamic Disk) is another
> >volume manager.
> >
> >Volume manager is a place to implement any kinds of software RAID. It’s
> primary purpose is to create a harddisk volume device object
> >(this is NOT a partition or physical disk device object) and to handle IO
> on it. On the upper end, it receives IRPs from the
> >filesystems. On the lower one, it talks to partition device objects and
> receive partition arrival-removal notification from PartMgr.
> >
> >Filesystems talk to volume manager’s device objects, not to Disk.sys ones.
> >
> >Both PartMgr and FtDisk are essential parts of the OS and are always loaded.
> >
> > Max
> >
> >
> >
> >—
> >You are currently subscribed to ntfsd as: xxxxx@giascl01.vsnl.net.in
> >To unsubscribe send a blank email to %%email.unsub%%
> >
> >
>
>
> —
> You are currently subscribed to ntfsd as: xxxxx@storagecraft.com
> To unsubscribe send a blank email to %%email.unsub%%
>

4

Thanks Max. But How does one write a Volume Manager. It seems I am now moved
out of the frying pan into fire.

Can you recommend any reading for that?

Basudeb

At 01:10 AM 3/18/02 +0300, you wrote:

You must write your own volume manager for this.

Max

----- Original Message -----
From: “Basudeb”
>To: “File Systems Developers”
>Sent: Saturday, March 16, 2002 6:29 AM
>Subject: [ntfsd] Filter for RAID and File System
>
>
>> Thanks Max. Is there any document or book or URL that has details on these
>> issues. Our problem is to create a Software RAID, but we do not know where
>> to put a filter. Is it possible to put a filter over volume manager? How
>> does one set the registry to do that?
>>
>>
>> Regards,
>> Basudeb
>>
>>
>>
>>
>> Return-Path:
>> Delivered-To: xxxxx@giascl01.vsnl.net.in
>> From: “Maxim S. Shatskih”
>> To: “File Systems Developers”
>> Subject: [ntfsd] Re: SYMEVENT.SYS
>> Date: Fri, 15 Mar 2002 21:55:49 +0300
>> Organization: StorageCraft
>> At 09:55 PM 3/15/02 +0300, you wrote:
>> >> How does WIN2k come to know the partition information of a hard disk?
>> >
>> >The disk driver+ClassPnP combo read the MBR record by IoReadPartitionTable
>> (which parses the MBR) and then creates device objects
>> >for each partition as a PnP bus driver.
>> >The have “STORAGE\Partition” PnP ID. PartMgr is a filter for this ID.
>> >
>> >> What are the functions of IOCTL_DISK_GET_DRIVE_LAYOUT &
>> >> IOCTL_DISK_GET_PARTITION_INFO in this matter?
>> >
>> >These ones are serviced by the disk driver which keeps the partition table
>> in its memory.
>> >
>> >> Also, what is partmgr doing as a disk filter?
>> >
>> >PartMgr handles partition arrival-removal. The volume managers register
>> themselves in PartMgr. PartMgr’s job is to report partition
>> >arrival-removal to the volume managers.
>> >The default volume manager is FtDisk.sys - for simple partitions and for
>> legacy NT4 FtDisk volumes. DmIo (Dynamic Disk) is another
>> >volume manager.
>> >
>> >Volume manager is a place to implement any kinds of software RAID. It’s
>> primary purpose is to create a harddisk volume device object
>> >(this is NOT a partition or physical disk device object) and to handle IO
>> on it. On the upper end, it receives IRPs from the
>> >filesystems. On the lower one, it talks to partition device objects and
>> receive partition arrival-removal notification from PartMgr.
>> >
>> >Filesystems talk to volume manager’s device objects, not to Disk.sys ones.
>> >
>> >Both PartMgr and FtDisk are essential parts of the OS and are always loaded.
>> >
>> > Max
>> >
>> >
>> >
>> >—
>> >You are currently subscribed to ntfsd as: xxxxx@giascl01.vsnl.net.in
>> >To unsubscribe send a blank email to %%email.unsub%%
>> >
>> >
>>
>>
>> —
>> You are currently subscribed to ntfsd as: xxxxx@storagecraft.com
>> To unsubscribe send a blank email to %%email.unsub%%
>>
>
>
>—
>You are currently subscribed to ntfsd as: xxxxx@giascl01.vsnl.net.in
>To unsubscribe send a blank email to %%email.unsub%%
>
>

5

The upper edge’s device objects created by VM (harddisk volumes) must carry MOUNTDEV_MOUNTED_DEVICE_GUID PnP interface.
The lower egde must register itself with PartMgr and receive PartMgr’s notifications on partition arrival. The partition device
objects are in these notifications. Your VM must send IRPs to them.

Max

----- Original Message -----
From: “Basudeb”
To: “File Systems Developers”
Sent: Monday, March 18, 2002 5:57 PM
Subject: [ntfsd] Re: Filter for RAID and File System

>
> Thanks Max. But How does one write a Volume Manager. It seems I am now moved
> out of the frying pan into fire.
>
> Can you recommend any reading for that?
>
> Basudeb
>
>
> At 01:10 AM 3/18/02 +0300, you wrote:
> >You must write your own volume manager for this.
> >
> > Max
> >
> >----- Original Message -----
> >From: “Basudeb”
> >To: “File Systems Developers”
> >Sent: Saturday, March 16, 2002 6:29 AM
> >Subject: [ntfsd] Filter for RAID and File System
> >
> >
> >> Thanks Max. Is there any document or book or URL that has details on these
> >> issues. Our problem is to create a Software RAID, but we do not know where
> >> to put a filter. Is it possible to put a filter over volume manager? How
> >> does one set the registry to do that?
> >>
> >>
> >> Regards,
> >> Basudeb
> >>
> >>
> >>
> >>
> >> Return-Path:
> >> Delivered-To: xxxxx@giascl01.vsnl.net.in
> >> From: “Maxim S. Shatskih”
> >> To: “File Systems Developers”
> >> Subject: [ntfsd] Re: SYMEVENT.SYS
> >> Date: Fri, 15 Mar 2002 21:55:49 +0300
> >> Organization: StorageCraft
> >> At 09:55 PM 3/15/02 +0300, you wrote:
> >> >> How does WIN2k come to know the partition information of a hard disk?
> >> >
> >> >The disk driver+ClassPnP combo read the MBR record by IoReadPartitionTable
> >> (which parses the MBR) and then creates device objects
> >> >for each partition as a PnP bus driver.
> >> >The have “STORAGE\Partition” PnP ID. PartMgr is a filter for this ID.
> >> >
> >> >> What are the functions of IOCTL_DISK_GET_DRIVE_LAYOUT &
> >> >> IOCTL_DISK_GET_PARTITION_INFO in this matter?
> >> >
> >> >These ones are serviced by the disk driver which keeps the partition table
> >> in its memory.
> >> >
> >> >> Also, what is partmgr doing as a disk filter?
> >> >
> >> >PartMgr handles partition arrival-removal. The volume managers register
> >> themselves in PartMgr. PartMgr’s job is to report partition
> >> >arrival-removal to the volume managers.
> >> >The default volume manager is FtDisk.sys - for simple partitions and for
> >> legacy NT4 FtDisk volumes. DmIo (Dynamic Disk) is another
> >> >volume manager.
> >> >
> >> >Volume manager is a place to implement any kinds of software RAID. It’s
> >> primary purpose is to create a harddisk volume device object
> >> >(this is NOT a partition or physical disk device object) and to handle IO
> >> on it. On the upper end, it receives IRPs from the
> >> >filesystems. On the lower one, it talks to partition device objects and
> >> receive partition arrival-removal notification from PartMgr.
> >> >
> >> >Filesystems talk to volume manager’s device objects, not to Disk.sys ones.
> >> >
> >> >Both PartMgr and FtDisk are essential parts of the OS and are always loaded.
> >> >
> >> > Max
> >> >
> >> >
> >> >
> >> >—
> >> >You are currently subscribed to ntfsd as: xxxxx@giascl01.vsnl.net.in
> >> >To unsubscribe send a blank email to %%email.unsub%%
> >> >
> >> >
> >>
> >>
> >> —
> >> You are currently subscribed to ntfsd as: xxxxx@storagecraft.com
> >> To unsubscribe send a blank email to %%email.unsub%%
> >>
> >
> >
> >—
> >You are currently subscribed to ntfsd as: xxxxx@giascl01.vsnl.net.in
> >To unsubscribe send a blank email to %%email.unsub%%
> >
> >
>
>
> —
> You are currently subscribed to ntfsd as: xxxxx@storagecraft.com
> To unsubscribe send a blank email to %%email.unsub%%
>

6

Hi Max, I am kinda interested in VM either. I was also wondering if it
possible that you recommend any books or URL about VM?

Thanks
Sarayooth
----- Original Message -----
From: “Maxim S. Shatskih”
To: “File Systems Developers”
Sent: Monday, March 18, 2002 6:36 AM
Subject: [ntfsd] Re: Filter for RAID and File System

> The upper edge’s device objects created by VM (harddisk volumes) must
> carry MOUNTDEV_MOUNTED_DEVICE_GUID PnP interface.
> The lower egde must register itself with PartMgr and receive PartMgr’s
> notifications on partition arrival. The partition device
> objects are in these notifications. Your VM must send IRPs to them.
>
> Max
>
> ----- Original Message -----
> From: “Basudeb”
> To: “File Systems Developers”
> Sent: Monday, March 18, 2002 5:57 PM
> Subject: [ntfsd] Re: Filter for RAID and File System
>
>
> >
> > Thanks Max. But How does one write a Volume Manager. It seems I am now
> moved
> > out of the frying pan into fire.
> >
> > Can you recommend any reading for that?
> >
> > Basudeb
> >
> >
> > At 01:10 AM 3/18/02 +0300, you wrote:
> > >You must write your own volume manager for this.
> > >
> > > Max
> > >
> > >----- Original Message -----
> > >From: “Basudeb”
> > >To: “File Systems Developers”
> > >Sent: Saturday, March 16, 2002 6:29 AM
> > >Subject: [ntfsd] Filter for RAID and File System
> > >
> > >
> > >> Thanks Max. Is there any document or book or URL that has details
> on these
> > >> issues. Our problem is to create a Software RAID, but we do not
> know where
> > >> to put a filter. Is it possible to put a filter over volume
> manager? How
> > >> does one set the registry to do that?
> > >>
> > >>
> > >> Regards,
> > >> Basudeb
> > >>
> > >>
> > >>
> > >>
> > >> Return-Path:
> > >> Delivered-To: xxxxx@giascl01.vsnl.net.in
> > >> From: “Maxim S. Shatskih”
> > >> To: “File Systems Developers”
> > >> Subject: [ntfsd] Re: SYMEVENT.SYS
> > >> Date: Fri, 15 Mar 2002 21:55:49 +0300
> > >> Organization: StorageCraft
> > >> At 09:55 PM 3/15/02 +0300, you wrote:
> > >> >> How does WIN2k come to know the partition information of a hard
> disk?
> > >> >
> > >> >The disk driver+ClassPnP combo read the MBR record by
> IoReadPartitionTable
> > >> (which parses the MBR) and then creates device objects
> > >> >for each partition as a PnP bus driver.
> > >> >The have “STORAGE\Partition” PnP ID. PartMgr is a filter for this
> ID.
> > >> >
> > >> >> What are the functions of IOCTL_DISK_GET_DRIVE_LAYOUT &
> > >> >> IOCTL_DISK_GET_PARTITION_INFO in this matter?
> > >> >
> > >> >These ones are serviced by the disk driver which keeps the
> partition table
> > >> in its memory.
> > >> >
> > >> >> Also, what is partmgr doing as a disk filter?
> > >> >
> > >> >PartMgr handles partition arrival-removal. The volume managers
> register
> > >> themselves in PartMgr. PartMgr’s job is to report partition
> > >> >arrival-removal to the volume managers.
> > >> >The default volume manager is FtDisk.sys - for simple partitions
> and for
> > >> legacy NT4 FtDisk volumes. DmIo (Dynamic Disk) is another
> > >> >volume manager.
> > >> >
> > >> >Volume manager is a place to implement any kinds of software RAID.
> It’s
> > >> primary purpose is to create a harddisk volume device object
> > >> >(this is NOT a partition or physical disk device object) and to
> handle IO
> > >> on it. On the upper end, it receives IRPs from the
> > >> >filesystems. On the lower one, it talks to partition device
> objects and
> > >> receive partition arrival-removal notification from PartMgr.
> > >> >
> > >> >Filesystems talk to volume manager’s device objects, not to
> Disk.sys ones.
> > >> >
> > >> >Both PartMgr and FtDisk are essential parts of the OS and are
> always loaded.
> > >> >
> > >> > Max
> > >> >
> > >> >
> > >> >
> > >> >—
> > >> >You are currently subscribed to ntfsd as:
> xxxxx@giascl01.vsnl.net.in
> > >> >To unsubscribe send a blank email to %%email.unsub%%
> > >> >
> > >> >
> > >>
> > >>
> > >> —
> > >> You are currently subscribed to ntfsd as: xxxxx@storagecraft.com
> > >> To unsubscribe send a blank email to %%email.unsub%%
> > >>
> > >
> > >
> > >—
> > >You are currently subscribed to ntfsd as:
> xxxxx@giascl01.vsnl.net.in
> > >To unsubscribe send a blank email to %%email.unsub%%
> > >
> > >
> >
> >
> > —
> > You are currently subscribed to ntfsd as: xxxxx@storagecraft.com
> > To unsubscribe send a blank email to %%email.unsub%%
> >
>
>
> —
> You are currently subscribed to ntfsd as: xxxxx@mizzou.edu
> To unsubscribe send a blank email to %%email.unsub%%
>

7

Maybe people from MS here can recommend something.

Max

----- Original Message -----
From: “Sarayooth Chittratanawat”
To: “File Systems Developers”
Sent: Monday, March 18, 2002 12:52 AM
Subject: [ntfsd] Re: Filter for RAID and File System

> Hi Max, I am kinda interested in VM either. I was also wondering if it
> possible that you recommend any books or URL about VM?
>
> Thanks
> Sarayooth
> ----- Original Message -----
> From: “Maxim S. Shatskih”
> To: “File Systems Developers”
> Sent: Monday, March 18, 2002 6:36 AM
> Subject: [ntfsd] Re: Filter for RAID and File System
>
>
> > The upper edge’s device objects created by VM (harddisk volumes) must
> > carry MOUNTDEV_MOUNTED_DEVICE_GUID PnP interface.
> > The lower egde must register itself with PartMgr and receive PartMgr’s
> > notifications on partition arrival. The partition device
> > objects are in these notifications. Your VM must send IRPs to them.
> >
> > Max
> >
> > ----- Original Message -----
> > From: “Basudeb”
> > To: “File Systems Developers”
> > Sent: Monday, March 18, 2002 5:57 PM
> > Subject: [ntfsd] Re: Filter for RAID and File System
> >
> >
> > >
> > > Thanks Max. But How does one write a Volume Manager. It seems I am now
> > moved
> > > out of the frying pan into fire.
> > >
> > > Can you recommend any reading for that?
> > >
> > > Basudeb
> > >
> > >
> > > At 01:10 AM 3/18/02 +0300, you wrote:
> > > >You must write your own volume manager for this.
> > > >
> > > > Max
> > > >
> > > >----- Original Message -----
> > > >From: “Basudeb”
> > > >To: “File Systems Developers”
> > > >Sent: Saturday, March 16, 2002 6:29 AM
> > > >Subject: [ntfsd] Filter for RAID and File System
> > > >
> > > >
> > > >> Thanks Max. Is there any document or book or URL that has details
> > on these
> > > >> issues. Our problem is to create a Software RAID, but we do not
> > know where
> > > >> to put a filter. Is it possible to put a filter over volume
> > manager? How
> > > >> does one set the registry to do that?
> > > >>
> > > >>
> > > >> Regards,
> > > >> Basudeb
> > > >>
> > > >>
> > > >>
> > > >>
> > > >> Return-Path:
> > > >> Delivered-To: xxxxx@giascl01.vsnl.net.in
> > > >> From: “Maxim S. Shatskih”
> > > >> To: “File Systems Developers”
> > > >> Subject: [ntfsd] Re: SYMEVENT.SYS
> > > >> Date: Fri, 15 Mar 2002 21:55:49 +0300
> > > >> Organization: StorageCraft
> > > >> At 09:55 PM 3/15/02 +0300, you wrote:
> > > >> >> How does WIN2k come to know the partition information of a hard
> > disk?
> > > >> >
> > > >> >The disk driver+ClassPnP combo read the MBR record by
> > IoReadPartitionTable
> > > >> (which parses the MBR) and then creates device objects
> > > >> >for each partition as a PnP bus driver.
> > > >> >The have “STORAGE\Partition” PnP ID. PartMgr is a filter for this
> > ID.
> > > >> >
> > > >> >> What are the functions of IOCTL_DISK_GET_DRIVE_LAYOUT &
> > > >> >> IOCTL_DISK_GET_PARTITION_INFO in this matter?
> > > >> >
> > > >> >These ones are serviced by the disk driver which keeps the
> > partition table
> > > >> in its memory.
> > > >> >
> > > >> >> Also, what is partmgr doing as a disk filter?
> > > >> >
> > > >> >PartMgr handles partition arrival-removal. The volume managers
> > register
> > > >> themselves in PartMgr. PartMgr’s job is to report partition
> > > >> >arrival-removal to the volume managers.
> > > >> >The default volume manager is FtDisk.sys - for simple partitions
> > and for
> > > >> legacy NT4 FtDisk volumes. DmIo (Dynamic Disk) is another
> > > >> >volume manager.
> > > >> >
> > > >> >Volume manager is a place to implement any kinds of software RAID.
> > It’s
> > > >> primary purpose is to create a harddisk volume device object
> > > >> >(this is NOT a partition or physical disk device object) and to
> > handle IO
> > > >> on it. On the upper end, it receives IRPs from the
> > > >> >filesystems. On the lower one, it talks to partition device
> > objects and
> > > >> receive partition arrival-removal notification from PartMgr.
> > > >> >
> > > >> >Filesystems talk to volume manager’s device objects, not to
> > Disk.sys ones.
> > > >> >
> > > >> >Both PartMgr and FtDisk are essential parts of the OS and are
> > always loaded.
> > > >> >
> > > >> > Max
> > > >> >
> > > >> >
> > > >> >
> > > >> >—
> > > >> >You are currently subscribed to ntfsd as:
> > xxxxx@giascl01.vsnl.net.in
> > > >> >To unsubscribe send a blank email to %%email.unsub%%
> > > >> >
> > > >> >
> > > >>
> > > >>
> > > >> —
> > > >> You are currently subscribed to ntfsd as: xxxxx@storagecraft.com
> > > >> To unsubscribe send a blank email to %%email.unsub%%
> > > >>
> > > >
> > > >
> > > >—
> > > >You are currently subscribed to ntfsd as:
> > xxxxx@giascl01.vsnl.net.in
> > > >To unsubscribe send a blank email to %%email.unsub%%
> > > >
> > > >
> > >
> > >
> > > —
> > > You are currently subscribed to ntfsd as: xxxxx@storagecraft.com
> > > To unsubscribe send a blank email to %%email.unsub%%
> > >
> >
> >
> > —
> > You are currently subscribed to ntfsd as: xxxxx@mizzou.edu
> > To unsubscribe send a blank email to %%email.unsub%%
> >
>
>
> —
> You are currently subscribed to ntfsd as: xxxxx@storagecraft.com
> To unsubscribe send a blank email to %%email.unsub%%
>