A particular portion of a program which can be read from on-disk representations of the program as well as from memory images of the program is identified for use as a version discriminator. A first representation of the portion may be obtained from a first memory image of the program, corresponding to a first running instance of the program. The first representation may be compared to a second representation obtained at a development environment. Based on the results of the comparison, a particular version of the program corresponding to the first running instance may be identified. An indication of the particular version may be stored.