• File Extension PDImage by Flickr.com, courtesy of Rick Audet
  
  

Flex Sign

• The *.PD extension was used to store a plotter or cutter document, usually used to make posters or oversized printouts, by the program Flex Sign 5 from Beacon Graphic Systems.
  
  

MRI

• *.PD files are also used to store data from MRI machines in the medical field.
  
  

Paradox Table

• Paradox tables hold information relevant to relational database management. Some programs store this data in *.PD files
  
  

Pearl

• In the pearl computing language, *.PD files are used to store processor information to make these programs run more efficiently.
  
  

Pipe Dream

• No longer in use, Pipe Dream was a word processing and spreadsheet program that stored its data in *.PD files.
  
  

Pure Data Patch

• *.PD files are utilized as pure data patch files in conjunction with images sounds and custom text.