title_body: SD Cards with Unusual File Types Background: My dad died last year and I inherited sd cards (not micro) in plastic cases. These cards have several directories that all end in .RES
  
  Each directory has about 30 files in it.
  Two of the 30 files in each directory have extensions: one is DATA.FRK and the other is RSRC.INF
  The other 28 files are each 4 letters long of random looking strings with no extension. Most of the files have a date from 2006
  
  I was able to open the RSRC.INF file and it looks to be an author's name and the title of a book? article? something.
  
  Questions:
  
  
  Can you tell me what is on these sd cards?
  Is there a windows software/opensource software that could read these
  files?
  Should I be looking for an old piece of ebook hardware or just
  reformat the cards and use them with an older model camera?
upvoted_answer: This sounds like IMP format. The IMP file is a container for other directories files, namely (1) directories ending in .RES and (2) files ending in .FRK and .INF. From mobileread.com (no affiliation):
  
  
    IMP is an intermediate file format used to store eBook content for several eBook Readers, most notably the eBookwise-1150 and the REB 1200. These devices are end user names for products called the ETI-2 and ETI-1 respectively from http://ebooktechnologies.com/ (no longer available) The Wayback machine displays the last time this site was available Jun 20, 2010. Site downloads are still available from http://www.ebooksystem.net/support_download.htm
  
  
  You can find a list of compatible software here.