March 27, 2003
Should You Let Airport Security Scan Your Magnetic Tapes and Disks?
The risk of a lost bag is far greater than the risk of data corruption from electronic scanning.
If you’ve traveled by air, you’ve probably worried about whether your precious magnetic recordings, be they tape or disk, will survive inspection by airport security. With the installation of even higher- powered scanning equipment, the concern is even greater. Could these new, enhanced devices erase your data or are you just wringing your hands over nothing?
While erasure is highly unlikely, there are reasons to be cautious, particularly if you are transporting older tape formats or floppy disks.
Check It In or Carry It On?
According to new guidelines issued by the Transportation Security Administration, or TSA, 100% of all checked bags must be screened before being loaded. During the screening process, checked bags may go through as many as three types of scanners including X-ray and two different types of explosive detection systems. Still, it is doubtful that these systems will have a negative impact on magnetically recorded media. In fact, the TSA says, “None of the screening equipment…will affect digital camera images or film that has already been processed, slides, videos, photo compact discs, or picture discs.”
But the main concern for media in checked bags isn’t electronic damage — it’s physical loss. Airport personnel have the authority (and the duty) to open and inspect any suspicious bag, including any bag that is locked. (HINT: Leave your bags unlocked.) With your bags out of your control, the risk of damage, loss, or even theft is greatly increased. Therefore, you should always carry-on your tapes, disks and any other valuables.
Passenger Checkpoints: Handheld Wands, Metal Detectors, X-Rays
Okay, so you’re going to carry-on your tapes. But, they’ll have to go through similar scanning systems. Can these systems cause data loss? Probably not. To understand why, you need to understand how magnetic media is recorded.
Data is written onto tape and discs by arranging metallic particles with a powerful magnetic field. For tapes, magnetic energy is delivered by a recording head that comes into direct contact with the tape. For disks, the record head floats just above the surface. Both methods deliver a great deal of magnetic energy in close proximity to a tightly confined area.
To scramble your carefully arranged magnetic particles from a distance takes a tremendous amount of magnetic energy. How much energy depends on the distance and the coercivity of the media — the magnetic force required to “coerce” it into zero magnetism.
Floppy disks have a very low coercivity rating. In other words, it doesn’t take much magnetic energy to scramble them. Ditto for non- metal audio cassettes. Older videotape formats based on metal oxide like 3/4 inch, VHS and 8mm also have low coercivity ratings. At the opposite end of the scale are modern tape formats using pure metal particles or pure evaporated metal formulations. These tapes which include DVCAM, MiniDV, Hi8, and Betacam SP, have very high cocercivity ratings and are the most resistant to erasure.
Obviously, X-Rays are not magnetic and won’t cause problems themselves. There has been some conjecture that magnetic energy created as a byproduct of producing X-Rays and even conveyor belt motors might give some cause for concern. However, damage from these sources has not been well documented.
Direct sources of magnetic energy come from the walk-thru metal detectors and handheld wands. While it is doubtful that either of these devices would cause problems, some handheld wands, in theory, do generate enough magnetic energy to corrupt data on low-coercivity formats. Our practical experience, however, has not confirmed this.
Unlike magnetic media, X-ray will most certainly ruin undeveloped film. While the TSA states that film below 800 ASA/ISO would be unaffected by passenger checkpoint X-ray, it also says that the cumulative effect of multiple passes through these devices can fog even low speed films.
According to the TSA and based on reports from customers, manufacturers and our own personal experiences, it is highly unlikely that any of the scanning devices in use today would corrupt magnetically recorded media. Your most likely source for trouble is damage or loss from the hand inspection of a checked bag. If you’re still concerned about passenger checkpoint scanners you can always ask security to hand-inspect your bags. It may take longer, but a little inconvenience may be a small price to pay for the peace of mind of knowing that your data is safe.
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This article originally appeared in www.tapeonline.com Comments? We’d love to hear from you. Give us some feedback about this article or tell us about your recent airport experiences. Drop us a line at: firstname.lastname@example.org.