Volumes in Mac OS are sections of hard drive formatted with file system. Mac OS does not recognize the volume until and unless it is formatted with file system. The operating system does not identify the volume and cannot access the data inside it. The common file systems used by Mac OS are HFS, HFS+ and HFSX file system. Volumes are not same as partitions in Windows operating system. Hard disk can be further divided into multiple partitions to increase the performance, reliability, and security of the system. By creating partitions, you can have multiple operating systems on the same hard drive and files can be separately located from other program files. In Mac, you have disk utility application to divide the hard drive into volumes. It is installed with the operating system. File system organizes and manages the file that keeps track of the allocation information of the files. Previously in Mac, file consists of two parts called data fork where data is stored and resource fork where file metadata and application information is stored. Volumes contain allocation blocks and logical blocks. When you save a file in Mac OS, File Manager assigns the file to allocation block. Mac OS provides three types of partition schemes like GUID (Globally unique identifier), MBR (Master boot record) and Apple partition map. Apple partition map is default partition table provided by Mac. Files are retrieved using the allocation information stored in file system.
When you delete a file from volume, it moves to Trash, which stores the deleted data. Journaling feature records details of changes to files on disk. As every modification of the file is stored in it, you can easily recover deleted files using this information. Some of the common scenarios in which files are deleted or lost are corruption of volume header, third party application failure, power surge problems, journal corruption etc. As soon as you recognize that files are deleted or lost stop using that volume immediately from where the files have been deleted or lost. When a file is deleted, only the allocation information of the file is deleted, and not the data in the file. This free space can be utilized by new data. Therefore, continuous storage of data on the volume leads to overwriting and deleted data cannot be recovered easily using software also.
If you have backup for your important data then no need to worry because you can restore it back easily. So, it is always suggested to take backup of data periodically. However, if proper backup is not available, you will need to make use of a powerful Mac Undelete software to recover deleted files. The precautions to be taken to prevent data from being overwritten are, do not save any file further on the volume, do not download or install any third party application on the affected volumes etc.
Mac undelete volume helps you to undelete Mac Trash and lets you recover deleted Mac files from Lion and other recent versions of Mac like Leopard and Snow Leopard. You can simply drag and drop the software in the application folder to install it. This software performs rigorous scanning to recover lost files from inaccessible volumes and also helps to undelete files from crashed hard drive on Mac. This tool performs signature search to identify files and restore data from Mac partition files. As journal enabled volumes in Mac keeps track of all the changes done on disk, the software easily recovers the data from these volumes without performing signature search using this information. The powerful recovery algorithms of the tool has the potential to restore deleted files from Mac hard drive and from the Mac volumes that do not mount or refuse to mount. The tool can also undelete files from external hard drive on Mac easily.This software can also restore data from iMac hard disk lost due to accidental format, malware infection, sudden system shut down and hard drive corruption. The software is also capable of recovering deleted / lost photos on Mac OS X. This Mac Undelete Tool additionally lets the user perfrom Mac iPhoto Library restoration.
Steps to undelete files from Mac OS X:
Step 1: Download and install the trial version of the software. Start the program by double clicking the desktop shortcut. The main window is displayed as shown in Figure a. Select “Recover Volumes / Drives” option from the main window to undelete files from Mac volume.
Figure a : Main Screen
Step 2: When you select “Recover Volumes / Drives” option, a new window is shown. The new window gives you an option to restore files from Mac volume. Select “Volume Recovery” option and proceed to the next step as shown in Figure b
Figure b: Select Formatted/Reformatted Recovery Option
Step 3: Select the drive from which you want to retrieve files/data and click on “Next” as shown in fig c.
Figure c: Select Volume
Step 4: The software starts scanning the selected volume and displays the recovered data as shown in Figure d
Figure d: restored Files