I'm trying to figure out how to work with an operating system called GS-DOS. (Full name appears to be 'General Software Embedded[v2]'). It is being used in a handheld barcode scanner I have been asked to work with, in the hopes that I can figure out how to program it. I have no real experience with any DOS platform, but I have noticed that not all of the DOS commands I've seen online will work with this particular DOS setup.

Google searches on the full name turn up nothing, and searches on the GS-DOS extension merely wish to know if I meant 'MS-DOS' instead.
Does anyone know where I could find some kind of tutorial or instructional guide to dealing with GS-DOS?

some googling turned up this

GD-DOS Manual

http://www.embeddedarm.com/Manuals/DOSROM41.PDF