Monthly Archives: April 2012

Windows 8, ReFS, and Extended Attributes

By now, a lot of my readers will be aware of the new ReFS file system in Windows 8. I personally believe ReFS will evolve, and will add support for some of the missing features. To recap, some of the features present in NTFS, but absent from ReFS (at least the ReFS in Windows 8 include:

  • No support for Extended Attributes
  • No support for Alternate Data Streams
  • No support for quotas
  • No support for bootable volumes

This is not a comprehensive list. I decided to look briefly at each of these features in a series of blog posts.

Extended Attributes are known to be used in two specific cases, if one believes some of the postings on the Internet, including on Technet forums. To be clear, I am not attributing these postings to Microsoft employees, I am simply saying users have posted on some Microsoft owned forums:

  • Internet Explorer and Windows use Extended Attributes to mark files downloaded from the Internet and provide a security warning when the user attempts to execute the file.
  • Windows Client Side Caching (yes, the name keeps evolving) uses Extended Attributes to mark files in its cache

What, if anything else, uses Extended Attributes ?

Since there was no convenient way, I wrote a small utility to examine a specified directory and inspect each of its component files and sub-directories to determine if any of them have Extended Attributes. I am happy to provide this utility free for any curious folks. I ran the utility on a Windows 8 Server box and a partial output is at the end of this blog.

What I found is that a number of Windows system files and directories use Extended Attributes.

It will be interesting to see what path Microsoft takes to improve ReFS functionality e.g. if and when Microsoft enhances ReFS to provide support for bootable volumes, will ReFS evolve to support Extended Attributes, or will Windows evolve to stop using Extended Attributes.

Here is the promised partial output

Directory \??\C:\Documents and Settings has Extended Attributes.

Directory \??\C:\ProgramData\Application Data has Extended Attributes.

Directory \??\C:\ProgramData\Desktop has Extended Attributes.

Directory \??\C:\ProgramData\Documents has Extended Attributes.

 File \??\C:\ProgramData\Microsoft\Windows\Hyper-V\Resource Types6FF76FA-2D58-4BAF-9F8D-455773824F37.xml has Extended Attributes.

File \??\C:\ProgramData\Microsoft\Windows\Hyper-V\Resource Types\118C3BE5-0D31-4804-85F0-5C6074ABEA8F.xml has Extended Attributes.

File \??\C:\ProgramData\Microsoft\Windows\Hyper-V\Resource Types\146C56A0-3546-469B-9737-FCBCF82428F4.xml has Extended Attributes.

File \??\C:\ProgramData\Microsoft\Windows\Hyper-V\Resource Types\19839BFF-6F04-4B24-B4B5-1AFCCBE729DE.xml has Extended Attributes.