What is Sid
Sid extension is related to MrSID map image file or Commodore 64 music. You can open sid files with Mrsid Viewer or Sidplay2 softwares.
There are two different areas that use sid extension:
1-MrSID Image File :
It is compressed image file which used for uninterrupted image archive. Generally it is used for mapping area. You can try to open sid files with Autocad software. Besides, you may download free image viewer software from firms official web page : lizardtech.com
2- Commodore 64 Audio File :
The audio files which used with old kinf of Commodore computers use sid extension. You can play sid extension files with a software called Sidplay.
Viewer or Converter for Sid
MrSID viewer , Sidplay2
Which pages about Sid