In short: John Andrews created DSL. Robert Shingledecker started contributing patches and got brought in as a developer; he created (among other things) the MyDSL extension system and a bunch of other goodies. DSL started falling apart organizationally, and Andrews "exiled" Shingledecker (in the latter's words) - so Shingledecker carried on with developing Tiny Core Linux instead.
In short: John Andrews created DSL. Robert Shingledecker started contributing patches and got brought in as a developer; he created (among other things) the MyDSL extension system and a bunch of other goodies. DSL started falling apart organizationally, and Andrews "exiled" Shingledecker (in the latter's words) - so Shingledecker carried on with developing Tiny Core Linux instead.