Odds are that if you check your purse or wallet right now, you'll find an invention that owes its existence as much to a desire for neatly pressed clothes as a need for portable data storage—the magnetic stripe card.
Conceived by IBM engineer, Forrest Parry, as part of a government security system project, the technique of attaching a strip, or "stripe," of magnetic tape to a card facilitated a revolution in portable, personal data retrieval. Until the advent of the chip-based smart card during the 1980s, the magstripe ruled—from club membership cards, through to phone, credit, and debit bankcards.
Parry had experienced several frustrating failures with trying to fix the magnetic material to the card with adhesive. When a forlorn-looking Parry returned home from the laboratory, his wife, who was ironing at the time, stepped in and suggested she try using the heat of the iron to bond the magstripe to the plastic. After a period of technical development, international standardization, and testing, the magstripe went into mass production. By the 1960s, they were being used by organizations as diverse as the London Underground transport system and the Central Intelligence Agency (CIA).
Today, the stripe is usually made from tiny magnetic particles secured in resin, which are either applied directly to the card or produced as a plastic backed stripe that is then attached to the card. Particles may be standard iron oxide, or, if a higher "coercivity" stripe is needed, barium ferrite. Information is written to a stripe by changing the polarity of its particles; as the coercivity is increased, the chances of accidental erasure are reduced—a factor of prime importance to card issuers and users alike.
