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Rawdisk and partially locked files ?

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Create virtual file systems and disks, expose and manage remote data as if they were files on the local disk.
Posted: 08/17/2009 14:18:15
by stephane  (Standard support level)
Joined: 03/17/2009
Posts: 39


Does the rawdisk driver/api handle "LockFileEx()" partially locked files (an example could be outlook.pst that is not entirely locked but only partially) ?

Outlook seems not to ask exclusive access to the whole pst file, so the application detects an "unlocked" file tries to copy it and fails in the middle of the operation.

If I ask an handle with TRawdisk.CreateFile() on a partially locked file, will I be able to completely read it (even on the locked region) ? will the driver detect it as a locked file or unlocked one ?

Posted: 08/18/2009 01:26:55
by Volodymyr Zinin (Team)


Unfortunately it isn't possible (at least in the current version) to access a locked region by the use of TRawdisk.CreateFile.
Posted: 08/18/2009 05:53:26
by stephane  (Standard support level)
Joined: 03/17/2009
Posts: 39

Thanks for your answer.

It there any plan in the near future for a driver version handling locked regions ?

Is there any solution with another eldos product ?
Posted: 08/18/2009 06:50:39
by Eugene Mayevski (Team)

It is possible to extend RawDisk with this functionality. This would cost $300 to the cost of the license.

Sincerely yours
Eugene Mayevski
Posted: 08/18/2009 07:36:37
by stephane  (Standard support level)
Joined: 03/17/2009
Posts: 39

Ok I understand.
What could be the delay of delivery of such modification ?

Thanks :)
Posted: 08/18/2009 07:45:52
by Eugene Mayevski (Team)

It will take us a 2-3 days to implement this function.

Sincerely yours
Eugene Mayevski
Posted: 08/18/2009 08:08:02
by stephane  (Standard support level)
Joined: 03/17/2009
Posts: 39

Before I ask my boss to buy the licence plus the modification could you just confirm me that with this modification I will be able to at least copy the entire content of an outlook.pst file (even if outlook is running of course) ?
[I know that this will not solve the "incoherence" issue of a mail arriving in mailbox in the middle of the file reading, but I want to be sure that I can at least save the file in "normal" conditions]

If he pays and then this does not work, I could put myself in some trouble :o)

Thanks a lot,
Posted: 08/18/2009 09:23:53
by Volodymyr Zinin (Team)

Yes. You will be able to make the entire copy of outlook.pst.
But there is a small problem - because RawDisk doesn't intercept file operations it isn't possible to make a "snapshot" for a file. RawDisk works in the following way - it contains a kernel mode driver and uses it to send I/O requests (that bypass file sharing and security mechanisms) to a destination file. But in the same time when RawDisk is performing a file reading another process can write to it and as a result the copy will be incorrect. But you can workaround the problem for example by obtaining the last write time for the file before and after its copying.
Posted: 08/18/2009 09:35:17
by stephane  (Standard support level)
Joined: 03/17/2009
Posts: 39

Thanks a lot for your detailed answer :)

Indeed I am aware that I can copy an inconsistent file if any write operation occurs before I terminate the read operation, but for a PST file this will occur less often than a database file, so I can accept the "risk".
But of course I will return some warning mechanism like the one you describe.

I will inform by boss , he will contact you directly to buy the licence I think.

Best regards,
Posted: 08/18/2009 16:28:17
by goubin dylan (Standard support level)
Joined: 09/19/2006
Posts: 13

OK, you may implement this function and we will buy the license as agreed with Oleg.

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200+ components and classes for digital security, signing, encryption and secure networking.



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