SIOD is a small-footprint implementation of the Scheme programming
language that is provided with some database, unix programming and cgi
scripting extensions.

The motivation behind SIOD remains a small footprint, in every sense
of the word, at runtime, at compile time, and in cognitive attention
required to understand how the system works enough to be able to
extend it as well as the author would have done the work himself.

About eight years have passed since that initial release.  It has been
possible to add a feature or two without contributing to the cause of
software bloat, with the code segment of the libsiod shared library
remaining under 75K bytes on a prototypical comparison machine like a
VAX.  Furthermore, as the richness of the C runtime library available
on most systems has improved over time, SIOD remains a useful kind of
glue to have in a software engineers toolbox.
