Carter G. Walker remembers the day her memories vanished.
After sending an e-mail to her aunt, the Montana freelance writer stepped away from the computer to make a grilled-cheese sandwich. She returned a few minutes later to a black screen. Data recovery experts did what they could, but the hard drive was beyond saving -- as were the precious moments Walker had entrusted to it.
"All my pregnancy pictures are gone. The video from my first daughter's first couple of days is gone," Walker said. "It was like a piece of my brain was cut out."
Walker's digital amnesia has become a frustratingly common part of life. Computers make storing personal letters, family pictures and home movies more convenient than ever. But those captured moments can disappear with a few errant mouse clicks -- or for no apparent reason at all.
For The Record
Los Angeles Times Friday September 15, 2006 Home Edition Main News Part A Page 2 National Desk 1 inches; 32 words Type of Material: Correction
Digital memories: Wednesday's Column One article on the dangers of losing materials stored digitally misspelled the first name of Jaron Lanier, the computer scientist who coined the term "virtual reality," as Jason.
It's not just household memories at risk. Professional archivists, those charged with preserving the details of society, tell a grim joke: Billions of digitized snapshots, Hollywood movies and government annals, they say, "will last forever, or five years, whichever comes first."
Socrates described memory as "a block of wax ... the mother of the muses. But when the image is effaced, or cannot be taken, then we forget and do not know."
Digital storage methods, although vastly more capacious than the paper they are rapidly replacing, have proved the softest wax. Heat and humidity can destroy computer disks and tapes in as little as a year. Computers can break down and software often becomes unusable in a few years. A storage format can quickly become obsolete, making the information it holds effectively inaccessible.
No one has compiled an inventory of lost records, but archivists regularly stumble upon worrisome examples. Reports detailing the military's spraying of the defoliant Agent Orange in Vietnam, needed for research and medical care, were obliterated. Census data from the 1960s through 1980s disappeared. A multitude of electronic voting records vanished without a trace.
Records considered at risk by the National Archives include diagrams and maps needed to secure the nuclear stockpile and policy documents used to inform partners in the war on terror. Much like global warming, the archive problem emerged suddenly, its effects remain murky and the brunt of its effect will be felt by future generations. The era we are living in could become a gap in history.
"If we don't solve the problem, our time will not become part of the past," said Kenneth Thibodaux, who directs electronic records preservation for the National Archives. "It will largely vanish."
Humans have long imprinted collective memories on available objects, inscribing stone slabs, marking paper, etching paraffin cylinders and finally encoding computer disks. Chinese astronomers of the Shang Dynasty etched the words "three flames ate the sun" onto an ox scapula to pass on their celestial observations.
Thirty-two centuries later, that "oracle bone" confirmed for today's scientists an ancient eclipse, which allowed them to recalibrate their understanding of how the sun affects the Earth's spin.
Suppose those early stargazers had scratched out their findings in secret code on a mud flat. In effect, that's what NASA did when it used digital tape to store spaceflight data from the 1960s and 1970s. The observations could have helped unravel today's climate change and deforestation mysteries, but by the 1990s most of the tape had degraded beyond recovery.
Federal practices haven't improved much since then. Leading archivists said that the records of George W. Bush's presidency would probably be far less complete than those of Abraham Lincoln's.
In Lincoln's day, scribes vigilantly penned events and actions momentous or minute. Trusted records were viewed as essential to legitimize government and preserve citizens' rights. The bureaucracy generated a fairly complete record of what the government did, including voluminous chronicles of the Civil War.
Future historians will have a harder time with Iraq war records, created in several digital formats, some of which are already obsolete, said David Bearman, president of Archives & Museum Informatics, a consulting firm in Toronto.
In 20 years, pushed aside by waves of cheaper technology, "those records will be very difficult, if not impossible, to retrieve," he said.
Digital files are also remarkably easy to destroy, by accident or design.
Just after the U.S. invasion of Panama in 1989, Air Force historian Eduard Mark was assigned to write a history of the campaign. When he found the right records, the officer in charge was seconds away from a single keystroke that would have purged every daily "situation report" prepared for the Joint Chiefs of Staff, data crucial to understanding the conflict.
Soon after, Mark had an epiphany.