Although hard drives remain the primary storage device for computer users, they are not the only storage mechanism that most people use. In addition to a computer’s internal hard disk, users may also rely on other types of storage media such as external hard drives, USB flash drives, SD cards, and the list goes on. What a lot of people don’t realize is that these alternative media types can sometimes be prone to failure, and you may occasionally have to attempt a data recovery for media other than hard drives.
Attempting data recovery on for media other than hard drives brings up two main questions. First, why does the potential for data loss exist on seemingly stable media, such as an SD card? Second, if data loss or data corruption does occur, how can you fix the problem and get your data back?
Let’s start by talking about some of the reasons why data loss or data corruption might occur. Problems with the data on removable media tend to have two main causes – abuse and wear.
Let me say up front that SD cards and similar types of flash media tend to be extremely reliable. Even so, it is possible to physically damage an SD card. I have seen someone damage an SD card by dropping it on the floor and accidentally rolling a chair over it. However, the damage is more often caused by the ways in which SD cards and similar storage devices are used.
Two of the more devices in which SD cards are used are cell phones and cameras, both of which tend to get dropped from time to time. Some devices, such as extreme sports cameras, tend to take even more abuse.
Consider my personal situation. I own more than a dozen GoPro cameras, all of which use SD media. Considering the abuse that these cameras take, they do an excellent job of protecting the media within them. Even so, I put these cameras through a lot by using them onboard RC aircraft (which occasionally suffer rough landings). I have also been known to use GoPro cameras for activities such as speed boat racing, scuba diving, spelunking, off roading, dog sledding, and even astronaut training (www.youtube.com/brienp). Needless to say, I have caused damage to cameras and to the media that they contain on more than one occasion.
The other reason data loss and data corruption may sometimes occur on SD cards or another removable media is because solid state media such as SD cards and USB memory sticks store data within the flash memory. Flash memory cells eventually wear out. Modern flash storage devices can typically handle roughly about 100,000 write operations. However, formatting such a device can shorten its lifespan since formatting may interfere with the device’s wear leveling mechanism. Flash cells can also fail prematurely if the card is exposed to static electricity.
The bottom line is that although SD cards and other forms of flash media tend to be extremely durable, they can and sometimes do fail. When such a failure does occur, the device’s data may be lost. This can be especially worrisome since such devices often contain irreplaceable items such as personal photos and videos.
So what can you do if data loss or data corruption do occur on an SD card or other external storage device? The good news is that data recovery tools, such as Data Rescue or Picture Rescue (designed specifically for digital media cards) can usually be used to recover data from failing removable media.
So why is that? Well, a removable media device isn’t all that different from the hard drive inside your computer. In fact, if you connect an SD card or a USB flash drive to your computer, it is usually made accessible through a drive letter, just like the PC’s internal hard disk. Furthermore, removable storage devices often use file systems that are similar to those used on hard drives.
SD cards, for example, use the same types of file systems that PCs do. Modern SD cards, for example, use file systems such as NTFS, FAT32, or exFAT. The actual file system used varies depending on the card’s capacity, manufacturer, intended use, and age.
NTFS and FAT32 have been the dominant file systems in the PC world for many years. Utilities that are designed to recover data from a damaged or corrupt hard disk usually work by analyzing the file system and attempting to reassemble the data. Because such utilities work at the file system level, they will work for any storage medium that uses a compatible file system, regardless of that media’s physical form factor.
If you do find yourself having to perform a data recovery operation on removable media, it is important to copy any recovered data to a different storage device. If data loss has occurred as a result of something other than you accidentally erasing the data then the storage device has probably sustained damage and, should, therefore, be considered untrustworthy.