Articles Tagged: computer hardware

The sickening possibility of data corruption

Digital photos are very fragile. Ask anyone who has had a hard drive crash. That kind of data loss is sudden and can be tragic. But it can be prevented if you have a good backup routine. Remember the cardinal rule: Data must be in at least two places and one of them must be off-site. Best practice is to have one local backup and one remote backup which could be a cloud service or another external drive that you keep at your aunt’s house.

The other kind of data loss that is more insidious is data corruption. It sometimes happens when you’re shooting but usually it’s later on, when the images are transferred and stored. If it happens in the camera or on your memory card you’ll see it right away as you’re shooting. If your photos ever have stripes or odd color bands while shooting, put another memory card in the camera. If the errors are still there you know it’s the camera. If they’re gone you know it was that other card.

Once the images are on your main hard drive is where the trouble can pop up. A digital image is made up of millions of “words” of digital information. If just one letter of one word gets switched or corrupted in some way it can destroy a photo. The more damage there is, the worst the visual effect is. This kind of damage is not reversible. What’s especially concerning is that you won’t usually notice the errors until you open up an image for years ago. Somewhere along the way the file was corrupted but you won’t know till you view it. That corrupt file has most likely been backup up so all copies will be damaged.

This kind of data corruption comes from three major sources. The first is an actual mechanical hard drive failure. The second is an electronic or connection issue. Disconnecting a hard drive while it is writing data will frequently result in corruption so be careful with your external drives and do not ever bump, drop or move a hard drive quickly. If you’re using a solid state external drive, or SSD, you’re in better shape since they are very resistant to physical trauma. The third, and most mysterious source of data corruption, is what’s called bit rot. This is the random corruption of those bits and bytes (the words) and it can happen at any time. This is a good overview of the problem. https://getprostorage.com/blog/bit-rot-stop-destroying-your-data/

There are a couple of ways to prevent bit rot. One is to buy a RAID storage system that does data scrubbing or parity checking. That just means that the device regularly looks through all the files and repairs them based on some fancy software. The other option is to convert all of your files to DNG format if you use Lightroom. DNG uniquely has data correction built in and you can, at any time, have Lightroom go through and check all the files through its validation routine. It can’t fix the corrupt files but at least you have time to replace them from a backup.

Having a favorite photo show up with green and pink stripes or grainy blocks is heartbreaking. Following some precautions will minimize that risk. One final way to prevent corruption? Print your favorite images or make a book! Neither of those crash or have to be loaded into a computer to enjoy.

Data Backup on the Road

Data on an SD or CF memory card is pretty safe. If you won’t be traveling long you could just take enough cards to handle the number of photos you’ll shoot and download them when you come back. Memory cards are cheap and don’t crash often, but they are pretty easy to lose. I’m not a fan of huge capacity cards for two reasons. If one does get corrupted you run the risk of losing all your photos. The more important reason is that if you’re shooting on a card that holds thousands of photos, you’re likely to make it through a whole week or trip before you fill one up. That means that your camera, which is the likeliest thing to get stolen that you’re carrying with you, has all your precious photo memories in it. If your camera is lost or stolen the pictures go with it. I prefer to have several cards of smaller capacity and leave the extra cards in the hotel room in plain sight. If they’re tucked away in your camera bag they are likely to be stolen along with everything else. A little paranoia can pay off when protecting digital files.

Get a good memory card holder or wallet. My favorite by far is the Pixel Pocket Rocket by Think Tank. It comes in two sizes, one for CF and one for SD cards. It folds over, holds your cards securely, holds business cards and has a fob with a clip. This is a great idea and one that gives me a lot of peace of mind. I clip that thing to a ring on my camera bag or loop in my jacket and don’t have to worry about accidentally dropping all my memory cards in a river or through a subway grate.

Favorite memory card holder: Pixel Pocket Rocket by Think | Favorite storage device: Samsung T5

If you want to backup your data while you’re traveling, there’s a temptation to just download them into your laptop, then reformat the card and shoot some more. Don’t do this! You have moved your data from a very secure, low theft device like a memory card to the spinning hard drive or SSD memory in your shiny, more-likely-to-be-stolen laptop. If you want to use your laptop, either keep the data on the cards as well or take an external hard drive with you to backup the files on. My favorite storage device is the Samsung T5. It’s available in .5, 1 and 2TB. They are much more expensive than external hard drives but they are tiny, lightweight, fast and completely not prone to physical crashes the way hard drives are. The laptop and hard drive shouldn’t be in the same bag at the same time to avoid a total loss in case of theft. Data backup maxim: Data should be stored in at least two places at all times, and one of those should be in another location.

Gefen DVI Detective

Well, here’s a product I didn’t know existed but was happy to find. About a year ago I built a new machine for the studio, mostly to run Lightroom. I like Lightroom and want to love it, but have had speed problems with it since day one. So I built a quad core machine with 8gb ram, fast ATI card (had conflicts with the Nvidia) and a serious RAID 6 controller from Areca for storage and cache. For my viewing pleasure I got two 27″ displays from Doublesight and glued it all together with Vista 64. The problems began when I had to install a couple of DVI video extension cables to the monitors. Every time the screen blanker kicked in, or when the machine was restarted or came out of sleep mode, the monitors wouldn’t come up at the right resolution or even left to right sequence. About half the time I had to go in and reset the layout and resolution. It was one of those really frustrating things that I let go for two long.

While I was trying to get some HDMI problems solved (another day, another rant!) I asked John Johns, the video wizard at In-Sync, Inc. in Dallas, what he would recommend. He referred me to Gefen, a company that makes a crazy array of video conversion boxes. On their website I found a little box called the DVI Detective and an explanation of what the problem was with my monitors (and my HDMI troubles). Both of those connections transmit an EDID code. According to Wikipedia: “Extended display identification data (EDID) is a data structure provided by a computer display to describe its capabilities to a graphics card. It is what enables a modern personal computer to know what kind of monitor is connected.” As with many things electronic, that doesn’t always work out in practice. What was happening was the EDID wasn’t being picked up and weird things were happening.

The DVI Detective goes inline between the computer and the monitor. You power it up with the included wallwart, push a tiny button on the little box, a light flashes telling you the code is being received and stored, you flip a switch to lock the setting – and you’re done. The power can now be unplugged. I was hesitant to spend 2 x $60 (from Buy.com) on these little gizmos but my problem is completely solved. I love these things.

They are tiny boxes and come with nice, stout turn around DVI patch cables. A solid product that does exactly what it claims to with very little setup. This is what the mess looks like behind my monitors until I dress this up a little:

gefen-dvi-detective2-Dallas-Center-for-PhotographyUPDE: 7-4-09
I’ve been using the Gefen DVI Detective boxes for a few weeks now and I can happily report that they have completely solved the problems I was having! Money well spent.