I have uploaded a new SRFI-96 to
http://swiss.csail.mit.edu/~jaffer/srfi/srfi-96.html with some
clarifications and a new Issues section:

  Issues

  It would be good to have a definitive set of operating-system names
  for software-type.  RFC-3232 says that the operating-system list
  which originated in RFC-952 and ended with RFC-1700 is no longer
  defined by a RFC:

      Since 1994, this sequence of RFCs have been replaced by an
      online database accessible through a web page (currently,
      www.iana.org).  The purpose of the present RFC is to note this
      fact and to officially obsolete RFC 1700, whose status changes
      to Historic.  RFC 1700 is obsolete, and its values are
      incomplete and in some cases may be wrong.

      We expect this series to be revived in the future by the new
      IANA organization.

  That was in January 2002.  The revival has not occurred.  The web
  page seems to be
  http://www.iana.org/assignments/operating-system-names.  Last
  updated 2002-04-29, it is six years out-of-date.  Even for the the
  operating-systems it does address, it isn't consistent.  Some
  operating-systems appear without version; some appear only with
  versions; some appear both ways.  MSDOS appears without a hyphen or
  version while the entries for SunOS are SUN-OS-3.5, SUN-OS-4.0, and
  SUN.  For MicroSoft Windows there are 12 varieties (none with MS or
  Microsoft), all with versions separated by hypens and a lone WIN32.