AT: "xx" Bob Blackman was a Human Starfleet officer in the 24th century.
In 2354, he was named as a Starfleet Operational Support Services officer on a directory placard in Starbase 32, Maxia sector. His room number was 83412. Blackman shared this office with Carol Kunz. (TNG: "Violations", directory)
In the 2370s, he was named as a Yard Engineer on the dedication plaque of Federation starships. (DS9: "The Search, Part I", dedication plaque; VOY: "Caretaker", dedication plaque; DS9: "Valiant", dedication plaque; VOY: "Message in a Bottle", dedication plaque; DS9: "The Dogs of War", dedication plaque)
In an unknown, alternate future timeframe, he was named as a Tactical Systems officer on the dedication plaque of the USS Pasteur. (TNG: "All Good Things..." dedication plaque)