About Filter driver

NTDEV
1

I write a disk filter driver.
But when I add it at the first position in the registery, the driver works
well, and when I add it add it not the first time, it can’t work.

For example: (my filter driver’name is myfilter)

1). UpperFilters key valus is :

myfilter
VolSnap

the driver works well

2). UpperFilters key valus is :

VolSnap
myfilter

the driver can’t work

Who can help me? Thanks.

2

What exactly fails when you are not the first filter?

=====================
Mark Roddy DDK MVP
Windows 2003/XP/2000 Consulting
Hollis Technology Solutions 603-321-1032
www.hollistech.com

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Sun Jiajie
Sent: Tuesday, May 30, 2006 4:43 AM
To: Windows System Software Devs Interest List
Subject: [ntdev] About Filter driver

I write a disk filter driver.
But when I add it at the first position in the registery, the
driver works well, and when I add it add it not the first
time, it can’t work.

For example: (my filter driver’name is myfilter)

1). UpperFilters key valus is :

myfilter
VolSnap

the driver works well

2). UpperFilters key valus is :

VolSnap
myfilter

the driver can’t work

Who can help me? Thanks.

Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256

To unsubscribe, visit the List Server section of OSR Online
at http://www.osronline.com/page.cfm?name=ListServer

3

I define some control code, when I put the dirver at the first postion in
registry.
I can use DeviceIoControl(…,MyControlCode,…) to complete some action.
but when I don’t put it at first, it failed.
The GetLastError() error code 1.

“Mark Roddy” ???:xxxxx@ntdev…
> What exactly fails when you are not the first filter?
>
> =====================
> Mark Roddy DDK MVP
> Windows 2003/XP/2000 Consulting
> Hollis Technology Solutions 603-321-1032
> www.hollistech.com
>
>> -----Original Message-----
>> From: xxxxx@lists.osr.com
>> [mailto:xxxxx@lists.osr.com] On Behalf Of Sun Jiajie
>> Sent: Tuesday, May 30, 2006 4:43 AM
>> To: Windows System Software Devs Interest List
>> Subject: [ntdev] About Filter driver
>>
>> I write a disk filter driver.
>> But when I add it at the first position in the registery, the
>> driver works well, and when I add it add it not the first
>> time, it can’t work.
>>
>> For example: (my filter driver’name is myfilter)
>>
>> 1). UpperFilters key valus is :
>>
>> myfilter
>> VolSnap
>>
>> the driver works well
>>
>> 2). UpperFilters key valus is :
>>
>> VolSnap
>> myfilter
>>
>> the driver can’t work
>>
>> Who can help me? Thanks.
>>
>>
>>
>> —
>> Questions? First check the Kernel Driver FAQ at
>> http://www.osronline.com/article.cfm?id=256
>>
>> To unsubscribe, visit the List Server section of OSR Online
>> at http://www.osronline.com/page.cfm?name=ListServer
>>
>
>
>

4

Ah well somebody in the stack has decided to reject device control codes
that it doesn’t expect rather than putting them down the stack.
Microsoft has actually encouraged this behavior; at least somebody from
Microsoft did the last time this issue came up. I find it not such a
good policy as it results in people like you being forced into playing
the ‘topmost filter’ game. If you have to put your control operations
down the standard device stack, (rather than using a private control
device object), and if any filter above you thinks it ought to reject
control codes it doesn’t understand, then you have to force your filter
to be above that offending filter.

-----Original Message-----
From: xxxxx@lists.osr.com
[mailto:xxxxx@lists.osr.com] On Behalf Of Sun Jiajie
Sent: Tuesday, May 30, 2006 9:31 PM
To: Windows System Software Devs Interest List
Subject: Re:[ntdev] About Filter driver

I define some control code, when I put the dirver at the first postion
in
registry.
I can use DeviceIoControl(…,MyControlCode,…) to complete some action.
but when I don’t put it at first, it failed.
The GetLastError() error code 1.

“Mark Roddy” ???:xxxxx@ntdev…
> What exactly fails when you are not the first filter?
>
> =====================
> Mark Roddy DDK MVP
> Windows 2003/XP/2000 Consulting
> Hollis Technology Solutions 603-321-1032
> www.hollistech.com
>
>> -----Original Message-----
>> From: xxxxx@lists.osr.com
>> [mailto:xxxxx@lists.osr.com] On Behalf Of Sun Jiajie
>> Sent: Tuesday, May 30, 2006 4:43 AM
>> To: Windows System Software Devs Interest List
>> Subject: [ntdev] About Filter driver
>>
>> I write a disk filter driver.
>> But when I add it at the first position in the registery, the
>> driver works well, and when I add it add it not the first
>> time, it can’t work.
>>
>> For example: (my filter driver’name is myfilter)
>>
>> 1). UpperFilters key valus is :
>>
>> myfilter
>> VolSnap
>>
>> the driver works well
>>
>> 2). UpperFilters key valus is :
>>
>> VolSnap
>> myfilter
>>
>> the driver can’t work
>>
>> Who can help me? Thanks.
>>
>>
>>
>> —
>> Questions? First check the Kernel Driver FAQ at
>> http://www.osronline.com/article.cfm?id=256
>>
>> To unsubscribe, visit the List Server section of OSR Online
>> at http://www.osronline.com/page.cfm?name=ListServer
>>
>
>
>

—
Questions? First check the Kernel Driver FAQ at
http://www.osronline.com/article.cfm?id=256

To unsubscribe, visit the List Server section of OSR Online at
http://www.osronline.com/page.cfm?name=ListServer