Do airport x-rays damage the computer hardware

What causes an SD card to be corrupted?

There are several ways that an SD card can be damaged.

First, cards can actually be broken physically. You can bend them in half pretty easily if you try, but in general they are actually quite resilient. Many are effectively waterproof even if not marketed that way. I sent cards through the laundry and once threw a fully valuable baby photo straight into hot coffee - no problem! Well I wouldn't recommend pushing your luck, but it is unlikely if you are careful.

Electrostatic discharge can also damage electronics, although most cards are surprisingly tough. (Purposely try to destroy a card with static electricity and your success rate will be low.)

Flash isn't particularly sensitive to light, so airport x-rays aren't a real risk (prolonged exposure to high-energy x-rays is a different story). And magnets don't worry either - "A magnet strong enough to disrupt the electrons in lightning would be strong enough to suck the iron out of your blood cells," said the executive director of the Compact Flash Association.

It's also surprisingly heat-resistant - the plastic case is likely at higher risk than the memory itself.

The physical damage is at the most basic level. At the high end, corruption and data loss can occur without anything fundamental goes wrong. The firmware in cameras and card readers (i.e. the mini operating system and the software running on the device) can make errors or arise in situations that cannot be handled.

The most obvious thing is that if you pull the card out while you are trying to write on it, you can mess things up. Do not do that. (And keep in mind that with caching, this can take a while after you think the data transfer is complete.) With SD or Compact Flash cards, it's usually relatively safe to remove the card from a reader while it is in use is provided for read access. Note that this Not safe is if you have an xD card device.

An error may occur when deleting files or if the card is full. And it is theoretically possible that when formatting the card on a computer, it could conflict with file system errors.

Provided you avoid the card pull-out scenario and don't have a hardware failure. These are also quite rare as the file system implementations used in cameras have been around for a long time and are very well tested.

It is also possible that faulty cables, faulty USB connections, or problems in the computer itself can damage files in transit. Trying again on a different system is always a good first diagnosis.

In all of these cases, the card itself is really fine - reformat it and you can use it again.

Then there's the SD card that really damaged.

This is done in two ways:

Manufacturing defects

There is a lot of pressure to make small, inexpensive, high capacity devices. To achieve this, manufacturers have learned not to worry about perfection and use devices with around 2-5% of the already bad To be shipped directly from the factory. These initial bad blocks are hidden and shouldn't affect anything, but actually have a long-term effect - see below.

And it's possible that a given map might have a lot more in it than it should, including blocks that weren't hidden properly. This is much more likely with cheap cards.

Cumulative error

Flash memory inherently has a limited number of write / erase cycles. Inevitably, electrons are trapped where they are not wanted and the voltage levels shift, ultimately leading to read or write errors. Each bit of flash memory is reported for a certain number of cycles before failure, but it really is a random process and there could be a problem long before the numbers would average.

Coping Mechanisms

Since these things are inevitable, SD cards are designed to minimize the damage. In addition to masking bad blocks initially, they detect and mask new bad blocks as they appear. They are initially made with overcapacity, and when the blocks wear out, spare blocks are transparently replaced so everything continues to work. The flash card's built-in controller uses error correction to prevent the errors from corrupting data as soon as they occur.

However, cheaper cards may have less sophisticated error correction and likely have less free capacity to cover up bad blocks.

Flash devices also use a Wear leveling so that write operations are distributed across the entire device and do not always use the same area. Again, cheap cards can make this worse.

It is worth buying quality branded cards as problems arise in the last section. Even then, failure is inevitable (like death and taxes). So don't put all your eggs in the same basket - make sure you have backups. Other than that, the main piece of advice is to be careful when writing.


Name stamp is the way to go, but beware of counterfeit cards. It is often difficult to tell if you really have a SanDisk, Lexar, etc. card. Look for "Counterfeit SD Card" - it's not a short list :( This is definitely a case of "You get what you pay for".