In a previous article, I argued that understanding data recovery is crucial to understanding how you can avoid data loss, by applying simple preventative practices in your photographic or videographic life. Here, I help you build on that by making five specific actionable suggestions.
(1) Take enough cards to avoid having to delete files, or delete only the most recent picture
If you must delete an image, do so immediately before you take the next image. In this way, you maintain the contiguous write structure that I previously said was important to being able to recover data later in case this is needed. Out-of-sequence deletions risk fragmentation of your storage medium, meaning that some data will not be recoverable – specifically, any data that is subject to fragmentation, so the more out-of-sequence deletions you make, the worse the situation may get.
(2) Transfer files to hdd in the field, either via laptop or special device
It’s a good idea to back up your data even when you’re still in the field and away from communication opportunities or on poor bandwidth. The ways of doing this range from using your laptop as a conduit to something like a pair of rugged hard drives like the ones by Lacie, to using hard drives that are also card readers, such as My Passport Wireless drives from Western Digital, or finally transfer using a dedicated backup device such as a Gnarbox. The reason the latter category of device hasn’t greatly caught on is presumably that laptops are both lightweight and affordable now, more versatile and can also be wrapped to be reasonably shock- and weatherproof.
In any case, you’d ideally back up redundantly, i.e. to two physical devices, or perhaps a mobile RAID array (mirrored, i.e. RAID 1), which is more convenient in the short term, but offers more points of failure.
(3) Keep the original memory cards intact until your data is safely backed up at home
Some pros now do not touch their memory cards while travelling, but rather pack them safely away even if they do additionally back up while on the road. Memory cards are now so cheap that you can almost treat them like film in the old days. So keeping hold of your filled memory cards until they’re safely backed up at home is a very good and surprisingly affordable option.
(4) Resist all temptation to edit data on any of your backup media while on the road and especially do not re-save to the same file!
Generally, do not start editing until you have safely backed up. On the simplest level, any editing carries a risk of corrupting data or accidental deletion, but there’s also the additional risk that you may save back to the same file, i.e., your backup copy! Not only may you lose the original state of the file (if shooting JPEG, say), but in overwriting the original, the size of the file may change, leading any additional size to spill over into some free space on your storage medium. You’ve thus created a fragmented, unrecoverable file, and this is most likely to happen to your best images, obviously, because those will be the ones you’ll be keenest to edit. So, hard as it may be, leave them alone until you’re back at home! (If that’s where you back up your files.)
(5) Empty your cards completely
When you’ve completely backed up everything and you’re ready to release your memory cards or what have you from their duties, make sure you empty them completely. Formatting is the simplest and perhaps most reliable way of doing this, and once you’ve done so, you can be reasonably certain that when data is written on the card again, it will be in a contiguous pattern, maximising the chance of data recovery, should you ever need it.
(Bonus recap) Use HDD, not SSD!
If you only started reading this week, I strongly recommend you read the previous installment in this series – in order to understand why HDDs are better than SSDs for storing data in a recoverable state, you have to understand a few things about how hard drives work, and how that’s different from solid state drives (SSDs).
To recap briefly, hard drives are written sequentially, starting on the innermost “lane” and moving outwards. Where each file sits is written in the master file table (MFT). In addition, the end of each file is demarcated by a special EOF (end of file) character. In an ideal case where files are written contiguously (i.e. without being broken up into smaller pieces (fragments) scattered over multiple places, i.e. “fragmented”), the original files would be recoverable after a deletion or loss of MFT data by simply reading the drive and starting a new file whenever an EOF character is encountered. Filesystem metadata like creation and modification times, file names and hence filetypes, would be missing because these are stored in the master file table. However, these can be brought back by looking at each file and recognising its type based especially on typical header structure, or other features on the data, or even trial and error. (If you know what data was stored on the drive, you’re in a good position to take a well-educated guess of what type a file might be, especially given its size!) As I mentioned, this is explained in more depth and also with illustrations in the first part of the series.