This page contains Information for .sd1 file extension and what type of programs that opens .sd1 Extension. You may find multiple entries for same Extension on this page. And because there are many associations for a same file extension
XnView - Dali Raw Image
file extension, also called filename extension, it is the suffix at the end of a filename after the (.), which indicates what kind of file it is. for example, you can tell that the file "computer.png" is a Portable Network Graphic Image, based on the ".png" file extension.