I would agree with Daniel in that the beginning of the novel Roberta and Ethan contrast one another in their views of programming and technology, then Roberta is forced into it and takes quite a liking to it.  The two have an unquenchable obsession with it, however Roberta’s obsession does not nearly elevate to the magnitude that Ethan has. The two still remain contrasting even in the end in the fundamental ways of thought and action.

Ethan’s obsession led to psychotic behavior and alienation of Joanna, who at one point loved and adored him.  It let to the blocking out of even severe signs from Joanna in the form of the abortion, “no you won’t” while she was leaving for India, and her postcard.  These few, but very clear signs were overshadowed by his obsession.  Ullman also presents his psychotic behavior quite clearly by illustrating how he wears his headband to isolate himself and block out any background noise.  He also darkens his workspace, as if to be only aware of the computer.  Any noise irritates him to an irrational degree, and Ethan also starts drinking an exorbitant amount which leads him toward even more psychotic behavior towards his neighbors.  Ethan had descended into pure madness, doing nothing in a healthy manner.

Roberta only shares the title of obsession with Ethan, not the degree.  Even though Roberta lets things she would normally care about slip, she still exhibits normal and sound minded behavior throughout the novel.  She, unlike Ethan, did not spend weeks at a time preforming the same action day in and day out without care of the world, she used her mind to think about the problem.  The main difference between the two is that Roberta, unlike Ethan, was an emotionally sound person, and did not let her obsession with programming allow her to hurt the people she loved, or the ones that loved her.  Ethan hurting Joanna ultimately led to his demise.  In addition to this main difference, Roberta contrasted Ethan in that she was not in a quest to find life in a computer, she was not under the delusion that it could be done, or under the obsession to create it.

Ethan in many ways resembles Victor Frankenstein, in the way that his obsession with science and creating life leads him to destroy all of his relationships, and in the end, himself.  He, like Victor, crumbles under the weight of his own deluded psychotic mind, and dies alone.  The song in this video of Frankenstein parallels their sins and struggles in many ways.