Or are we talking TB in the sense that a character keeps executing the last order given, such as a thief in the rear of the party continuously firing arrows at the nearest target until ordered to do something different?
I don't know what you mean by TB, but if a character in the party can keep doing anything, it isn't TB. In fact, I don't think there is any such thing as an auto attack in turn based systems. Just think of how DOS operates to get an idea of TB. Have you played DOS1 and/or 2?
TB = Turn Based But "Turn Based" can mean several different things. I go through some of the possibilities, six possibilities if memory serves, in an earlier post.
When I see "DOS" I think "Disc Operating System." So no, I doubt I played DOS1 or DOS2 because I don't recognize those as game names. Probably my only relevant experiences game wise are playing "Betrayal at Krondor" and "XCom" which have turn based combat systems. The former is an RPG and the latter is more of an isometric squad level tactical wargame. I think both combat systems fall into the "IGoUGo with reaction" category of TB systems. The vase majority of my experience with TB combat systems is with tactical and strategic wargames.
While not an RPG "Steel Panthers" (and the much more recent Panzer Corps and Panzer Corps 2 series of TB games) is and example a phased Turn Based with reaction tactical wargame that permits units to act independently by firing when an enemy unit comes within range. So, for example, tanks, self propelled AT guns, towed AT guns, and towed field artillery can have their engagement ranges set to fire at any target that moves into its field of fire within that range. Thus when the other side moves during its turn my units can react if the right conditions are met).
Baldur's Gate and BG2, and if memory serves also in the "Icewind Dale" series and the "Temple of Elemental Evil," can play like a TB game by setting auto pause only for rounds and then not manually pausing at any other time. The characters then follow the last order given each turn until they die or are given a new order. That includes automatically engaging in melee combat if any enemy gets close enough, or ranged combat at any enemy within range and a LOS. I don't remember if that version of the D&D rules had 1 minute combat turns with 10 six second action/initiative rounds per turn, or if a six second round and turn were functionally the same thing. I don't remember how combat worked in the Neverwinter Nights games or D&D Daggerdale. I think they were RTwP, but I'm not sure because it has been too long since I've played them. Also, Daggerdale is more of D&D as an isometric FPS with RPG elements.