I'm not sure how you define CS0, but my understanding is that there are now three introductory CS courses at Harvard: CS1, CS50, and CS51. Note that I graduated in 2007, so my understanding may be dated.
CS1 is intended for non-concentrators or people with very little prior CS experience.
CS50 is the standard intro course that most CS concentrators (or people considering CS as a concentration) take. Although it's taken by non-concentrators, most of the non-concentrators taking the course do so because they're in some field that has a lot of exposure to programming (e.g. Applied Math).
CS51 is the "advanced" intro course and is usually not the first CS course a CS concentrator takes, if for no other reason that it's not offered until the spring semester.
Comments
I'm not sure how you define CS0, but my understanding is that there are now three introductory CS courses at Harvard: CS1, CS50, and CS51. Note that I graduated in 2007, so my understanding may be dated.
CS1 is intended for non-concentrators or people with very little prior CS experience.
CS50 is the standard intro course that most CS concentrators (or people considering CS as a concentration) take. Although it's taken by non-concentrators, most of the non-concentrators taking the course do so because they're in some field that has a lot of exposure to programming (e.g. Applied Math).
CS51 is the "advanced" intro course and is usually not the first CS course a CS concentrator takes, if for no other reason that it's not offered until the spring semester.