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Chapter 15 Recovering Information

File Recovery Aids

Recovering Deleted Files (UNDELETE)


The operating system provides several methods of recovering deleted data. The chances of successfully recovering a deleted file depend on which method the operating system is able to use. This chapter provides an overview of file recovery and the recovery aids you can use to make this easier and more successful. See the command descriptions in the ``Command Reference'' chapter of DOSBook for more information about how to use the file recovery commands.

File Recovery Aids

Before you actually start deleting files, you should know how to use two utilities that the operating system provides to aid file recovery after delete operations: DISKMAP and DELWATCH. File recovery without either of these two methods is referred to as unaided.

DISKMAP

DISKMAP is a utility that copies and saves the File Allocation Table (FAT) of a disk. The FAT is like an index to a disk that records the location and size of all files on the disk. Running DISKMAP on a regular basis means that you always have a recent copy of the FAT, and the operating system can therefore retrieve information about a deleted file that it would not normally be able to retrieve. Refer to the ``Command Reference'' chapter of DOSBook for a description of DISKMAP.

DELWATCH

DELWATCH is another utility provided with the operating system that actually saves deleted files on the disk. Instead of removing a deleted file, DELWATCH simply marks it as a pending delete file. The file appears to be deleted, however. Using DELWATCH means that you are fairly sure of successfully recovering a deleted file. Refer to the ``Command Reference'' chapter of DOSBook for a description of DELWATCH.

Recovering Deleted Files (UNDELETE)

Use the UNDELETE command to recover deleted files, regardless of which method the operating system is able to use: DELWATCH, DISKMAP, or unaided. UNDELETE automatically determines and displays the method available.

By typing UNDELETE on the command line without a file specification, you can use a full-screen menu version of the UNDELETE command. The screen you see contains a list of the deleted files in your current directory and a series of menu options from which to choose. The list displays information about deleted files. You can select any of the following menu options:

By typing UNDELETE on the command line with a file specification, you start UNDELETE for the specified file.

For example, to recover a file called REPORT.TXT that you deleted from your current directory, you can do either of the following:

You are prompted about proceeding before UNDELETE attempts to recover REPORT.TXT.

Refer to the explanation about UNDELETE in the ``Command Reference'' chapter of DOSBook for more information about using this file recovery feature.

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