  Modern operating systems, browsers, and office suites have become megasystems
built on millions of lines of code. Their sheer size can intimidate even
experienced users and programmers away from attempting to understand and modify
the software running on their machines. This paper introduces system-specific
interpreters (SSIs) as a tool to help users regain knowledge of and control
over megasystems. SSIs directly execute individual modules of a megasystem in a
gdb-like environment without forcing the user to build, run, and trace the
entire system. A prototype framework to help write SSIs is described in this
paper and available for download at https://github.com/matthewsot/ssi-live22.
