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Love ‘em or hate ‘em, without memory cards our digital cameras would be as useful as a tap on a turnip.
And not only cameras: the cards are also found in PDAs, mobile phones, go-anywhere music players, robotic dogs, printers and laptops … even TV sets have card slots.
Many modern cameras build in significant amounts of memory so we can head out for a shoot without a moment’s hesitation. Yet the size of images today coupled with the digicam’s emerging talents as a video camcorder means that we need big dollops of portable memory.
They’re ultra small, decidedly clever, mostly reliable and offer remarkable storage capacities. But beware of their fragility … mistreat them and they’ll snap back with distressing damage.
To dig out a few facts on the technology and the use of memory cards, I spoke to Plamen Pazov of Xyber Technologies in Sydney, who helped with this story. His business is data recovery.
Memory cards rely on an implantation process which forces the electrons into an insulating layer within the chip itself. They get trapped there.
Because of that process of implantation, earlier memory cards had a very limited lifetime. Current ones are a lot better and reliability has increased to about a million write cycles.
Now the tricky bit: a single write cycle is not merely the action of writing a single image to the card. The cards write a single block at a time; this may total a couple of kilobytes each.
Even if the computer is not interfering with the data on the card it still continuously accesses the card. This action is similar to a write cycle. The longevity of your card is directly affected and can be decreased quite significantly.
Plamen, in his experience, has heard people say they’ve plugged their card into the computer and started reading the image directly from the card: “If you think about how many millions of times the computer will be accessing the card just to read parts of the picture, by reading and reading and rewriting — even small changes — you might reduce the card’s life expectancy by half just by reading a single picture.
The message: load your card, copy the images from it directly to your hard drive. Then take the card out.
Now at this point, I posed the question: if my pictures are ‘lost’, have they really gone?
You must remember that a card is a removable device as far as the computer and camera are concerned. It behaves in the same way as a small hard drive.
The card has an area called the directory. That area is very important as it keeps track of the files on the disc and on which sectors they’re written.
While that information may be missing, the rest of the data is still there but can’t be retrieved. Damage the directory and the card is useless — but you can’t access it in a meaningful way … the files are no longer complete entities.
The directory is ultra important. Many of the problems people encounter are caused by a damaged directory: it may have been overwritten or there’s a hardware problem with the card … some sectors cannot be read.
After a shooting session, download the pictures, then reformat the card in the camera. The camera then writes a clean directory, dispensing with leftover and unrelated entries. Reformat the card frequently.
If you have accidentally erased the card in the camera, the pictures may still be recoverable. It’s only when a camera has performed a ‘long erase’ that you may be unable to recover the images.