As I am just getting familiar with GPS via my discontinued nuvi 200 with limited capability, it would be good to get some insight into what is happening with GPS software. In the case of Garmin, it appears that newer units provide a user with software options not formerly available. For example, mapsource. I'm guessing there is more and probably revealed in some way to Garmin users via supplemental manuals.

Then there seems to be open (street) side to all this. I get the impression that this is sort of like Linux, or do your own. It may very well be, for example, that one constructs their on GPS maps or even a collection of people build a particular map. Again, I'm guessing.

What books or documents (web or otherwise) reasonably describe the state of all this GPS world?

Maybe I misunderstood, but I thought osm_routable_mapsource.exe was an install program for a program that would allow me to view maps on my PC. When I executed it, I found no executable, but did find some img files and a tdb file. Those plus an uninstall program. Isn't there supposed to be a program that allows me to view the img files?

I'm using Win7 and did get a message that the install may not have been satisfactory. It gave me a choice, and I selected It's OK.

I selected a number of California tiles from the map, and requested a build my map. The question is now what to do with the download of files to put the map on my Garmin?

There are four osm_routable files: mapsource, gmapsupp, roadtrip and tiles.
Three are zip,and mapsource is an exe. I would think one of them is what I
need to place on my nuvi. Perhaps mapsource prepares the img file.
All of the files are less than 10M?