Larry Jordan has recently been warning against the dangers of leaving drives on a shelf for periods over a year. He says that after a year, the data will start to essentially disappear. There's a way to avoid this effect of the vanishing data, and that's to have the computer read the entire disc.
Larry just posted an article on how to do this preventive action on his recent newsletter (not sure if this link will work for long, as these newsletters are only available for a limited time.) Here's the basics of the preventitive action.
-Make sure your user account has administrator access
-Open the Terminal applications, which is in the Utilities directory
-Enter this command: sudo cat /dev/rdisk0> /dev/null
Actually that command will read your entire boot drive, which is probably not the drive that has been sitting on a shelf for a year. You can run this task on different drives, but first you have to figure out the identifier for the drive (hint: it's not the name that you called the drive.)
To get the disk identifier, go to Disk Utility, also in the Utilities folder. Select the drive, not the volume--the drive's name usually starts with the capacity of the disk followed by the drive's manufacturer, e.g., Seagate, Hitachi, LaCie--the volume is what you named the drive or a partition on the drive. After selecting the disk that you want to run the maintenance on, click on the info icon at the top of the application window. This opens a new window with info on your drive, the disk identifer is the word "disk" followed by a number. If the disk identifier was disk2, then your command would be: sudo cat /dev/rdisk2> /dev/null
The command will take a while to run--we're probably talking hours. You can interrupt this procedure by hitting Control + C while in the Terminal.
Disappearing data is only one risk you run by using a hard drive as long-term storage. But this seems like something worth doing if you care about the data that you have left on a drive.
