Major Barlow was a member of SG-5 stationed at Stargate Command during the its early existence.
Biography
Background information
Major Barlow was assigned to be the commanding officer of SG-5 while Major General George S. Hammond was in command of Stargate Command and was in this role at the time SG-1 were scouting P7X-882. When a mishap caused Dr. Daniel Jackson to be trapped under a rock in a cave, Barlow and his team were assigned to accompany Dr. Janet Fraiser's medical team to the planet in order to rescue Jackson. Barlow and his team helped carry the equipment necessary to extract Jackson from his predicament and, after doing so, helped to carry Jackson back to the Stargate. (SG1: "Medical Considerations")