Garmin Forerunner 910XT and Linux
The Forerunner 910XT as well as other newer Garmin devices is/are using the wireless ANT+ protocol together with ANT-FS to transfer files from/to a PC. Note: ANT-FS means ANT File Share (not File System).
Garmin make use of so called FIT files, which are part of ANT+. Several FIT file types exists. The ones that bother me the most right now are the so called 'Activity' and 'Course' types.
If you are a runner an Activity file basically contains your run data, i.e. distance, time, laps, heartrate, elevation, position data.
You want Course files in order to follow some track someone else has ran previously or for tracks you create yourself on some kind of digital map e.g. within Google Earth or online tools like http://www.gpsies.com or http://www.bikeroutetoaster.com/.
At this point in time you can use Garmin-Forerunner-610-Extractor hosted on github to download files from a Forerunner 910XT.
Converting fit to tcx for example can be done with Fit-to-Tcx python tool which is also available on github.
Example Usage
Garmin-Forerunner-610-Extractor_Tigge] (167)$ python garmin.py Request basic information... Starting system... Open channel... Searching... String length: 16 Unit ID: 3843964727 Product name: Forerunner 910 3 128 144 574 1989-12-31 01:00:00 4 128 208 680 1989-12-31 01:00:00 5 128 208 1159 1989-12-31 01:00:00 6 128 208 317 1989-12-31 01:00:00 7 128 208 1159 1989-12-31 01:00:00 8 128 208 317 1989-12-31 01:00:00 9 128 208 1197 1989-12-31 01:00:00 10 128 176 1397 2012-03-30 20:55:54 11 128 176 1164 2012-03-30 23:30:38 12 128 176 1765 2012-03-30 23:38:56 13 128 176 4052 2012-03-31 22:06:38 14 128 176 7901 2012-04-01 12:19:08 15 128 176 14638 2012-04-01 13:51:24 16 128 176 36932 2012-04-02 13:30:34 17 128 176 5702 2012-04-03 09:13:26 18 128 176 19566 2012-04-03 19:56:56 19 128 176 51949 2012-04-04 13:52:50 20 128 240 31169 2012-04-01 22:30:00 21 128 208 72 1989-12-31 01:00:00 22 128 208 627 1989-12-31 01:00:00 23 128 144 72 1989-12-31 01:00:00 24 128 144 168 1989-12-31 01:00:00 25 128 208 72 1989-12-31 01:00:00 Done downloading 3-80-1989-12-31_01-00-00-574-416.fit Done downloading 4-80-1989-12-31_01-00-00-680-416.fit Done downloading 5-80-1989-12-31_01-00-00-1159-416.fit Done downloading 6-80-1989-12-31_01-00-00-317-416.fit Done downloading 7-80-1989-12-31_01-00-00-1159-317.fit Done downloading 8-80-1989-12-31_01-00-00-317-317.fit Done downloading 9-80-1989-12-31_01-00-00-1197-1197.fit Done downloading 10-80-2012-03-30_20-55-54-1397-1397.fit Done downloading 11-80-2012-03-30_23-30-38-1164-1164.fit Done downloading 12-80-2012-03-30_23-38-56-1765-1765.fit Done downloading 13-80-2012-03-31_22-06-38-4052-4052.fit Done downloading 14-80-2012-04-01_12-19-08-7901-7901.fit Done downloading 15-80-2012-04-01_13-51-24-14638-14638.fit Done downloading 16-80-2012-04-02_13-30-34-36932-36932.fit Done downloading 17-80-2012-04-03_09-13-26-5702-5702.fit Done downloading 18-80-2012-04-03_19-56-56-19566-19566.fit Done downloading 19-80-2012-04-04_13-52-50-51949-51949.fit Done downloading 20-80-2012-04-01_22-30-00-31169-31169.fit Done downloading 21-80-1989-12-31_01-00-00-72-72.fit Done downloading 22-80-1989-12-31_01-00-00-627-627.fit Done downloading 23-80-1989-12-31_01-00-00-72-72.fit Done downloading 24-80-1989-12-31_01-00-00-168-168.fit Done downloading 25-80-1989-12-31_01-00-00-72-72.fit
$ python ../FIT-to-TCX/fittotcx.py 19-80-2012-04-04_13-52-50-51949-51949.fit.fit > 19-80-2012-04-04_13-52-50-51949-51949.tcx
You can use the fit file directly for uploading to Garmin Connect for example.