[MadnessASAP]

It's can be traced back to the roots of each OS. Windows has it's heritage in the land of DOS where files had an 8 character name with a 3 character extension and that extension carried meaning for the OS.

Linux being of Unix ancestry which had no such concept as a file extension. It was the responsibility of the application or kernel to discern what type a file was. Typically by the first few bytes of a file and handle it appropriately.

I personally am a fan of the Unix way but I can see why some might prefer the DOS convention.

[D-Coder]

Speaking of heritage... 8+3 goes back at least to DECSystem-10 on PDP-10s.

[MadnessASAP]

Everything goes back to the PDP-10 we are all using the incestuous off-spring of DEC.

Whether that is good or bad is left as an exercise to the reader.

[NikkiA]

A lot of it came from RSX11 features that got rolled into the PDP-10 OSes.

[vincent-manis]

6+3 on DEC TOPS-10.