Bit rot, also called "format rot," is the inability to access digital data because the file format is obsolete and compatible applications no longer exist to read it. Digital files placed in archival storage are expected to last indefinitely and might not be retrieved until years later. Information saved on obsolete removable media is problematic. Magnetic tape drives are not available for all the myriad formats of the past. In addition, computers no longer come with floppy drives. However, as of 2019, inexpensive floppy drives are available that can be plugged into a PC via the USB port.
The Solution to Digital File Rot
One way to prevent archival bit rot is to be aware of format changes. Whenever a file format has been updated, the application that reads them will also be updated. Within a few years, users should open important documents and save them in the new format. For example, the original .DOC file format created by Microsoft Word in the 1980s became a legacy format after the new .DOCX format debuted in 2007. Because billions of .DOC files exist in the world, Microsoft has continued to support the old format in all subsequent versions of Word, at least for now. However, lesser known products may not provide such extended support. Fortunately, major format changes do not occur frequently. See data rot
and software rot