A GM contemplating the use of Digital Mind in her setting might wish to think specifically about what the computer mentioned in the description can do. Some possible variations are:
-it is dedicated to, and fully occupied by, running the character's consciousness. (With this option the Complexity of the computer is mostly unimportant unless the character's mind becomes separated from it and it is then put to other use.)
Or
-it runs the character's mind as a program. The amount of spare processing capacity for other use would emerge from whatever the GM sets for the Complexity of the character's computer and the character's consciousness as per the computer rules on page B472. (Note that according to the standard rules, a computer can run
two programs of its maximum complexity level. There do not appear to be rules for a program that would occupy both slots.) An interesting possibility is to add a Variable enhancement so the character could choose to run himself at a lower IQ to open processing capacity for programs.
Or
-it it is assumed to run the character's mind as an independent or background function, plus acts just like having a normally functioning GURPS computer in your character. The computer is essentially a straight up benefit of the Advantage, pretty much as if the description said " this trait includes Accessory: Computer". While there is no reason that an Exotic trait needs to match to any given TL, a GM wishing to reflect on the potency or realism of this benefit can consider Ultratech, pp. 21 which indicates that a personal computer (5lb, which will fit nicely into a human-sized head) has Complexity 5 at TL9. According to the Digital Mind description, such a computer would be supplied to a character with IQ10. This computer reaches Complexity 7 (good for IQ 14) at TL10 and Complexity 8 (good for IQ 16) at TL11.
The above is a distillation of some thinking provoked by
this thread. Thanks to Kelly Pedersen and Ketsuban for key points.