It appears that Sigma SD10 DSLR is not using any standard protocol for communicating with the computer. So I'm trying to get in touch with Sigma but apparently this company do not even have an online support query. Looks like I will have to send a FAX to request the protocol documentation, in the hope that I get a reply. Not holding my breath, seriously. According to a Sigma user, the monolithic Windows GUI software that comes with the camera is "extremely slow" according to some user.

Epson that claim they are "open" did not reply to my developer support inquiry about the RD-1 raw file format. The tech support sent me there, so I asked the tech support if they have a more appropriate answer. I still have another card in my hand in case. It is the same Epson, that despite not having provided any help, give gphoto as a solution for Linux developers... If they were as helpful as they had been for printers and scanner... (mental note: mirror all the documentation they provide, in case they do like Kodak and just discard it)