The Free On-line Dictionary of Computing (30 December 2018):
siod
    (Scheme In One Defun or Scheme In One Day)
   A small Scheme implementation in C by George Carrette
   , .  SIOD is arranged as a
   set of subroutines that can be called from any main program
   for the purpose of introducing an interpreted extension
   language.  It compiles to 20 kbytes of executable
   (VAX/VMS).  Lisp calls C and C calls Lisp
   transparently.
   SIOD supports symbols, strings, arrays, hash coding, file
   i/o (binary, text, seek), data save/restore in binary and
   text, interface to commercial databases such Oracle and
   Digital RDB.
   Version 3.0 runs on VAX/VMS,Unix, Sun-3, Sun-4,
   Amiga, Macintosh, MIPS, Cray, ALPHA/VMS, Windows
   NT and OS/2.  It can be compiled by most ANSI C compilers
   and C++ compilers, e.g. gcc -Wall.
   (ftp://world.std.com/pub/gjc/),
   (ftp://world.std.com/src/lisp/).
   Usenet newsgroup: news:comp.lang.scheme.
   (1994-02-18)