From a semiotic point of view, sequences of 0 and 1 stored in a piece of physical computer memory code not only digital text data (images, animation) but also the instructions used to transform these data in substance of expression (pixel on the screen, audio waves from the speaker) and the instructions to translate the substance into form of expression (visual composition, verbal texts, etc). Using a well-formulated metaphor by Negroponte, we can figure these sets of instruction as “bits that speak to other bits”. Intrigued by this dialogue, usually inaccessible because hidden in the computer “black box”, digital artist are exploring how to visualize it. One of these artists, Adam Marks, has created an interactive art piece, Calltrace, that visualizes the functions of actual computer software. The visual translation is made of coloured boxes and lines: each box is a function in the code, each line is a function call; functions appear the first time they are called. At the center of the work is Valgrind, a Linux-based debugger and profiler. Calltrace-client is a Mac OS running custom OpenGL code to turn calls in the program into visuals. The result is a syncopated coreography, it looks like a Vj performace. As in Code Profiles by Bradford Paley, a software that displays its underlying code and comments on itself, Calltrace unveils a virtual object as the algorithms constucting this very object.

Valentina Culatti