This report -- The Expanding Digital Universe: A Forecast of Worldwide Information Growth Through 2010 -- contains a ton of information, but it can be summarized very simply. Humanity is creating information in many different ways and lots of it. By 2010 (figure 2, page 3), humanity will create 1,000,000 petabytes of information, but only have storage space for 600,000 petabytes. (Perhaps some of that information/data will not need to be stored.) One problem is replication, which is eating up storage space. (Many copies do keep stuff safe, but it also uses more storage space.) And of course, keeping information available/readable long-term is a serious issue and will only grow worse.
You are likely worried about the longevity of your stuff. Good. You might want to skim the report so you can see the bigger picture and the long-term implications.
What is a petabyte? A gigabyte is 1000 megabytes. A terabyte is 1000 gigabytes. A petabyte is 1000 terabytes. [Addendum 2:11 p.m.: Okay, yes, the numbers should technically be 1024. The report- page 2 - uses 1000 for simplicity and I copied the information from the report.]
2:23 p.m. -- Sorry about the typos...more than usual. Sigh.
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