Filter altitude request
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A file system filter driver must have a unique identifier called an altitude that defines its position relative to other filters present in the file system stack.
To request a filter altitude identifier, send email in an ASCII text e-mail message to fsfcomm@microsoft.com with the subject: “Filter altitude request”. The body of the email must contain the below fields and corresponding information.
An altitude for this filter will then be e-mailed back to the specified contact e-mail address.
You can also send email to fsfcomm@microsoft.com to update information associated with existing altitudes.
| Field | Comment |
|---|---|
| Company name: | |
| Contact e-mail: | Provide a long-term company email alias, versus individual email. |
| Product name: | |
| Product URL: | |
| Product/Filter description: | A one paragraph summary to help Microsoft determine an appropriate altitude for the filter. |
| Filter filename: | |
| Filter type: | One of these values: Registry, FileSystem, Both |
| Filter start-type: | One of these values: Boot, System, Auto, Demand |
| Requested filter load order group: | See Load order groups and altitudes for the list of available groups. |
| Requested altitude: | You must request an altitude allocation in the appropriate load order group or groups for your filter. Microsoft reserves the right to assign an altitude that is different from the requested altitude, depending on altitude availability and the filter driver functionality. |
| Additional information: | Use this field to let us know if there is any information you would like Microsoft to consider when assigning an altitude to this filter. |
The following is an example for the body of an allocation request email.
Hi,
Below is the request information to assign an altitude for our Contoso DataKleen file system minifilter.
Company name: Contoso Ltd.
Contact e-mail: filterdevgroup@contoso.com
Product name: Contoso DataKleen
Product URL: http://fsfilters.contoso.com
Product/Filter Description: The Contoso DataKleen filter removes all occurrences of any byte having a value between 128 and 255 during file reads. Our minifilter removes this value since it is not displayable on TTY devices.
Filter filename: ContosoDK.sys
Filter type: FileSystem
Filter start-type: Demand
Requested filter load order group: FSFilter Content Screener
Requested altitude: 268400
Additional information: None
Thanks,
FilterDev
Note
- All fields must be filled out.
- It may take Microsoft up to two weeks to process and assign altitudes. Any missing information may delay the assignment.
- The assigned altitude will eventually be reflected in the altitudes listed in Allocated Altitudes.