When a file appears lost where does it go? Contrary to what most people think, delete doesn't mean gone and the file doesn't disappear off the hard drive forever. It's best to think of the computer file as a page in a book. When the file is deleted, that page is not destroyed like it was torn out and put through a shredder. Instead, the table of contents that points out the location of that page is erased. The part that gets erased on your computer is the tiny bit of information that points to the location of the file on the hard drive. Eventually, the hard drive will write new data over the area where the old file is located. The pointer, along with other pointers for every folder and file on the hard drive, is saved in a section near the beginning of the hard drive and is used by the operating system to create the directory tree structure. By erasing the pointer file, the actual file becomes invisible to the operating system, even though it is still there until the file system reuses the space.
The challenge in recovering data is finding the original table of contents which can tell where the files actually exist. Qualified data recovery companies have experienced engineers that can rebuild the file system structure and save those lost files from being overwritten. That said, it's a matter of reaching those hidden places to recover data that appears to be gone forever. Data Recovery providers are often able to recover 100% of the data, but how is it done? Data recovery is the science of putting the file system back together so that the data files can be accessed. Every operating system has a file system, which is a unique method of indexing and keeping track of the files. Unfortunately for those that lose data, file systems can be very complex, which is why it can be so difficult to locate missing files. For instance, file systems that are used in business environments require security details and access transaction details. A good example is a transaction-based or journaling file system, whose goal is to log when each file is accessed, modified or saved - making the file system more complicated and harder to rebuild.
The best data recovery companies have developed proprietary tools to work with all of the main file systems in use today. Recovery engineers are internally trained to work on data recovery, working with computer hardware for a number of years and learning the low-level specifics of every type of file system. Rather than using third-party tools and employing an 'Auto-fix' on all of the file system errors to automatically fix the file system, recovery engineers are taught to discover the cause of the file system error and then to fix the file system in the best interests of the data and the client. Many jobs actually require the file system to be repaired by hand. After the file system is repaired, it is often necessary to repair the internal structure of data files themselves. Like file systems, today's business software data files are incredibly complex as well. In fact, some of the most common files used every day by users are more intricate internally then the file system that is storing the file! This is why it is important that recovery companies have developed file repair software utilities for Word, Excel, PowerPoint, Access, Outlook, and also database recoveries on Microsoft Exchange server and Microsoft SQL server. There are two phases when a storage device arrives for data recovery. The first phase is the diagnosis. The goal of this phase is to produce a file listing showing all the files that can be recovered. The safest method is to always work on a copy of the client's drive, never working on the original drive. During this stage, recovery engineers can determine if the drive requires special attention from the cleanroom, which is an ultra-clean environment used when working with microscopic components.
The cleanroom will work at an electronic and mechanical level to get the drive operational. This can include anything from physically cleaning the disk platters so they can spin properly to swapping out electrical components to power up the drive. After the drive is operational and a copy of the drive can be made, data recovery engineers work to repair the file structures and produce a complete file listing that shows all of the files and directories on the volume. This file listing will also tell the customer if there are holes (or Input/Output errors) within the file itself. The final phase is the recovery phase. The goal of this phase is to copy out the data and backup that data on media that the customer requires. It is also during this phase that the client can request some of the files to be tested within the lab. For example, on drives that have sustained severe media damage, the customer could ask to have some of the more common files to be tested.
The engineer that worked on the job will try to open some of the files and see if the data is present. When looking at how data recovery works, it's important to understand that data recovery is a highly skilled discipline that takes years of practice to establish credentials. Recovering data is made possible by constant research and development, and proficiency with working on storage technology as it is developed. Knowledgeable engineers that are highly trained and tested have the skills and technical expertise to know how to handle every data recovery job - ensuring you have the means to protect your data and provide them with additional value.
