Click here to Skip to main content
11,491,598 members (75,105 online)
Click here to Skip to main content

Reading MTF Backup Files

, 4 Apr 2007 CPOL 63.2K 1.1K 31
Rate this:
Please Sign up or sign in to vote.
An article explaning how to read backup files created with the Microsoft Tape Format (MTF) specification.

Screenshot - BackupReader.gif

Introduction

We use the NTBackup utility to backup our files at the office. Recently, one of the backup files turned out to be corrupt. Searcing for a solution, I came upon William T. Kranz's freeware ntbkup utility. Although ntbkup did a great job recovering the backup file, it is a command line utility. So, I decided to write a backup reader with a GUI.

Background

Volume, file, and folder information in a MTF backup file is stored as so called Descriptor Blocks. MTF is a linear file format. Reading a MTF backup file is a straightforward process. A backup file contains Data Set Descriptor Blocks, which are followed by Volume Descriptor Blocks. Volume Descriptor Blocks are followed by Directory Descriptor Blocks, which are in turn followed by File Descriptor Blocks.

Each descriptor block is followed by one or more Data Streams. Data streams are used for various purposes. They can be used for padding, storing checksums, long file/folder names, etc. One or more data streams associated with a file descriptor block typically contain file data.

Using the code

To read a backup file, an implementation creates a new instance of the CBackupReader class, passing the name of the backup file as an argument. Then, a catalog is created using the CCatalogNode class. The CCatalogNode class has a tree structure. The root of the tree is the backup file itself. Its child nodes represent the data sets in the backup file. Each data set node contains one (and only one) volume node. Volume nodes contain folders and files as child nodes. To extract a file from the catalog, one traverses the tree to reach the file and calls the ExtractTo method of the CCatalogNode class.
// Open the backup file
CBackupReader mFile = new CBackupReader(mFileName);
// Read the catalog
CCatalogNode node = mFile.ReadCatalog();
// Extract a node from the catalog
node.ExtractTo(mFile, mTargetPath); 

Limitations

  • Backup Reader was tested with a few relatively small backup files. The largest backup file tested was about 2 GB.
  • Compressed and encrypted archives are not supported.
  • Backup Reader works on Windows archives only. Although descriptor block definitions for other operating systems are included in the source code, they are not tested.
  • Archives that span multiple tapes/disks are not supported.

References

  1. ntbkup - William T. Kranz's freeware backup utility
  2. MTF specification and a Linux backup reader with C source code

License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Share

About the Author

Ozgur Ozcitak

Turkey Turkey
No Biography provided

Comments and Discussions

 
GeneralError on Backup Reader Pin
YasharGhassemi18-Apr-10 3:05
memberYasharGhassemi18-Apr-10 3:05 
QuestionHow can I use this code to read SQL SERVER BACKUP Files (*.bck)? Pin
VENKAT SEERLA10-Feb-10 21:35
memberVENKAT SEERLA10-Feb-10 21:35 
GeneralCompile this code Pin
ananon10-Jan-09 10:54
memberananon10-Jan-09 10:54 
GeneralIs it compatible with Veritas BKF Structure Pin
Maverick Debasish31-Dec-08 23:59
memberMaverick Debasish31-Dec-08 23:59 
GeneralRe: Is it compatible with Veritas BKF Structure Pin
Ozgur Ozcitak6-Jan-09 1:54
memberOzgur Ozcitak6-Jan-09 1:54 
GeneralRe: Is it compatible with Veritas BKF Structure Pin
Maverick Debasish6-Jan-09 6:04
memberMaverick Debasish6-Jan-09 6:04 
Generalerror to compile Pin
icelso20066-Oct-07 13:18
membericelso20066-Oct-07 13:18 
GeneralRe: error to compile Pin
r_stevenz24-Nov-08 16:07
memberr_stevenz24-Nov-08 16:07 
QuestionAny help will be appreciated Pin
SaeidehV30-Sep-07 23:34
memberSaeidehV30-Sep-07 23:34 
I’m using ntbackup.exe as a process in my application to backup some files and then your class for restoring the data.
Everythibg is ok if I run my application(in C#) from my hard disks, but I have to deploy my application on flash memoty
And when I run my application from the flash memory ntbackup.exe works well and backups the files successfully but after finishing the backup process my application does not work properly and I got this error from different part of my application ( when I want to show a new form in the form initializecomponent() method)
************** Exception Text **************
System.Runtime.InteropServices.SEHException: External component has thrown an exception.
at System.IO.UnmanagedMemoryStream.ReadByte()
at System.IO.BinaryReader.ReadByte()
at System.IO.BinaryReader.Read7BitEncodedInt()
at System.Resources.ResourceReader.LoadObjectV2(Int32 pos, ResourceTypeCode& typeCode)
at System.Resources.ResourceReader.LoadObject(Int32 pos, ResourceTypeCode& typeCode)
at System.Resources.RuntimeResourceSet.GetObject(String key, Boolean ignoreCase, Boolean isString)
at System.Resources.RuntimeResourceSet.GetObject(String key, Boolean ignoreCase)
at System.Resources.ResourceManager.GetObject(String name, CultureInfo culture, Boolean wrapUnmanagedMemStream)
at System.Resources.ResourceManager.GetObject(String name, CultureInfo culture)
at BaseMVC.BaseMVCResource.get_View()
at BaseMVC.Browser.BrowserFrm.InitializeComponent()

I searched a lot but I could not find a solution (even I wrote the Application.DoEvents() in my code but it does not work)
I’d be thankful if you can guid me?
FYI,I copied the ntbackup.exe on my flashdisk and it does not work properly there either ?!
Thanks in advance,
Saeideh

GeneralSQL MTF Pin
DanielSass2-Sep-07 5:30
memberDanielSass2-Sep-07 5:30 

General General    News News    Suggestion Suggestion    Question Question    Bug Bug    Answer Answer    Joke Joke    Rant Rant    Admin Admin   

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.

| Advertise | Privacy | Terms of Use | Mobile
Web01 | 2.8.150520.1 | Last Updated 4 Apr 2007
Article Copyright 2007 by Ozgur Ozcitak
Everything else Copyright © CodeProject, 1999-2015
Layout: fixed | fluid