Intermediate 
The vice-president of Google has warned that piles of digitized material  blogs, tweets, pictures, videos and official documents such as court rulings and emails  could be lost forever because the programs we need to view them will become defunct. Our first steps into the digital world could be lost to future historians, Vint Cerf told the American Association for the Advancement of Sciences annual meeting. He warned that we faced a forgotten generation or even a forgotten century because of what he called bit rot, where old computer files become useless junk.
Cerf says we need to develop digital methods to preserve old software and hardware so that out-of-date files can be recovered even if they are really old. When you think about the quantity of documentation from our daily lives that is captured in digital form, like our interactions by email, peoples tweets and all of the world wide web, its clear that we could lose an awful lot of our history, he said. We dont want our digital lives to fade away. If we want to preserve them, we need to make sure that the digital objects we create today can still be viewed far into the future, he added.
What is bit rot and is Vint Cerf right to be worried? Accessing digital content in the future could be less of a problem than Cerf thinks. His warning highlights an irony at the heart of modern technology, where music, photos, letters and other documents are digitized in order to ensure their long-term survival. But, while researchers are making progress in storing digital files for centuries, the programs and hardware needed to read the files are continually falling out of use.
We are throwing all of our data into what could become an information black hole without realizing it. We digitize things because we think we will preserve them. But what we dont understand is that, unless we take other steps, those digital versions may not be any better, and may even be worse, than the artefacts that we digitized, Cerf says. If there are photos you really care about, print them out.
Ancient civilizations did not have these problems because histories written on clay tablets or sheets of papyrus needed only eyes to read them. To study todays culture, future scholars would be faced with PDFs, Word documents and hundreds of other file types that can only be interpreted with special software and sometimes hardware, too.
The problem is already here. In the 1980s, it was routine to save documents on floppy disks and buy computer games on cassettes. Even if the disks and cassettes are in good condition, the equipment needed to run them is now mostly found only in museums.
Cerf warns that important political and historical documents will also be lost to bit rot. In 2005, American historian Doris Kearns Goodwin wrote Team of Rivals: the Political Genius of Abraham Lincoln. She went to libraries around the US, found the physical letters of the people involved and reconstructed their conversations. In todays world, those letters would be emails and the chances of finding them will be incredibly small one hundred years from now, said Cerf.
He concedes that historians will take steps to preserve material considered important by todays standards. But he argues that the significance of documents and correspondence is often not fully appreciated until hundreds of years later. Historians have learned how Archimedes, the greatest mathematician of antiquity, considered the concept of infinity and anticipated calculus in 3BC after his writings were found hidden under the words of a thirteenth-century prayer book. Weve been surprised by what weve learned about an earlier civilizations from objects that have been preserved only by chance, he said.
Researchers in Pittsburgh have made progress towards finding a solution to bit rot. Digital snapshots of computer hard drives are taken while they run different software programs. These can then be uploaded to a computer that copies the one the software ran on. The result is a computer that can read defunct files.
Inventing new technology is only half the battle, though. It could be even more difficult to obtain the legal permissions to copy and store software before it dies. When IT companies go out of business, they may sell the rights to someone else, which makes it very difficult to get approval. To do this properly, the rights of preservation might need to be incorporated into our thinking about things like copyright and patents and licensing. Were talking about preserving them for hundreds to thousands of years, said Cerf.