Pretend a file as read-only

Tony,
What would be your recommendation about the knowledge level and effort
required to do this kind of work.
The requirement to offer shared access has to be strong enough to afford
the time and effort.

Harish
-----Original Message-----
From: Tony Mason [mailto:xxxxx@osr.com]
Sent: Wednesday, June 10, 2009 9:20 PM
To: Windows File Systems Devs Interest List
Subject: RE: [ntfsd] Pretend a file as read-only

Malcom,

I disagree. We’ve made this work before, with single-writer,
multi-reader semantics on top of an NTFS file system shared across a
Fibre Channel. The “shadow file object” technique was, in fact,
something we invented (this is a long time ago) precisely to implement
this functionality (and since then we’ve used that same shadow file
object technique a number of times.)

As it turns out, we were stymied by a bug in NTFS at the time - it
caused an internal NTFS memory leak that would run the system out of
memory after 24 hours or so. But for that 24 hours, you had a shared
NTFS file system.

It was an interesting project.

Tony


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> filesystem takes care of all the hacks for you. Unfortunately (IIRC)

support for this in NTFS was added more recently (2003?),

XP


Maxim S. Shatskih
Windows DDK MVP
xxxxx@storagecraft.com
http://www.storagecraft.com