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Cannot recover data after preparing tape media


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This article was previously published under Q256065

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Summary

If you accidentally prepare a tape that contains data, you cannot retrieve any data by using typical programs or tools after the tape drive finishes writing an End of Data (EOD) marker on the tape.

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More information

Before an "unrecognized" tape can be used by any Removable Storage Manager-aware programs, it must be prepared. This operation writes a "free" media label on the tape, and then moves it to the Free media pool. Removable Storage Manager-aware programs can then pull new media from the Free pool and into their own dedicated pool. For more information about media labels, click the following article number to view the article in the Microsoft Knowledge Base:
250468� How Removable Storage Manager and programs recognize media
When you are using Removable Storage Manager (RSM) to prepare tapes, you receive the following warnings:
Confirm Media Preparation

This operation will destroy the data on the media and move it to the free pool.

Are you sure you want to write a free media label on the selected medium?
-and-
Confirm Media Preparation

Are you sure you want a free media label on "tape_name"?
After you confirm preparation, RSM mounts the tape and writes a free media label. After a software label is written, the tape drive writes an EOD marker on the tape. Once this EOD marker is recorded, any data contained past the EOD marker is permanently inaccessible. There are no software tools available to recover data that resides past the hardware EOD marker.

If you accidentally prepare a tape that contains data (no matter which pool the tape was in before the preparation), you cannot retrieve any data by using typical programs or tools after the tape drive finishes writing an EOD marker on the tape.

The Windows 2000 Resource Kit contains a utility named Mtfcheck.exe that you can use to confirm that the tape contains an EOD marker at the beginning of the tape. The following sample Mtfcheck.exe output demonstrates the output from running Mtfcheck.exe against a newly prepared tape. Notice the EOD at tape position Phy:2.
Copyright (c) 1998-99  Microsoft Corporation 

Microsoft tape format(MTF) verification tool. Version 1.24(4/29/99)
This utility check a given media family to make sure that
its format is fully compliant with Microsoft specifications. 
  
===========================================================

Physical Parameters: 
	Physical Block Size: 1024     
	Format Logical Block Size: 1024
	SoftWare Name preparing this tape:Removable Storage Service\ 
	Media Name is Free Media Label 7\ 
	[ERROR] Stream header data couldn't be read.

	[NOTE] Some inconsistency in TAPE header stream.
[Media State] End of data mark has been found at Tape position <Phy:2, FLA:0>
				
NOTE: It may be possible to send the tape to a third-party data recovery firm that has a special tape drive to skip past the EOD marker to recover data. For more information, click the following article number to view the article in the Microsoft Knowledge Base:
244923� Deleting backup catalog may erase backup set member tapes

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Keywords: KB256065, kbinfo

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Article Info
Article ID : 256065
Revision : 7
Created on : 10/3/2007
Published on : 10/3/2007
Exists online : False
Views : 437