資料來源 : Free On-Line Dictionary of Computing

Portable Scheme Debugger
     
        (PSD) A package for source code debugging of {R4RS}-compliant
        {Scheme} under {GNU Emacs} by Kellom ?ki Pertti
        .  Version 1.1.  Distributed under {GNU} {GPL}.
        It works with {scm}, {Elk} and {Scheme->C}.
     
        {(ftp://ftp.cs.tut.fi/pub/src/languages/schemes/psd.tar.Z)}.
     
        (1992-10-08)