Release notes for version 1.9

A new C FFI as added, thanks to Crestani, Harald Glab-Plhak. The old one is still there but will eventually be phased out. See Crestani's paper Foreign-Function Interfaces for Garbage-Collected Programming Languages".
A new networking code layer was added with full support for IPv6, UDP etc. (undocumented as of yet)
Records now support single inheritance (accessible through the r6rs-records packages)
letrec* was added to the `scheme' structure
A r5rs structure was added.
A new condition system based on R6RS's system has replaced the old system.
Some R6RS libraries were added (with help from Robert Ransom).
A statistical profiler was added (Marcel Turino, Manuel Dietrich) - check the documentation for details.
TLC tables (eq? tables) were added by Marcus Crestani and David Frese.
The module system warns on cycles and redefinitions
When the VM is compiled with GNU C, it uses direct threading for instruction dispatch, which speeds up the VM noticeable (done by Timo Harter)
The reader for a structure is configurable (again).
SRFI 19 now works on Windows
list-spine{,-cycle-safe}[*%] sequence macros were added to reduce structure by Robert Ransom
The Windows build can be done via a Boo script (contributed by Robert Ransom)
The unquote and unquote-splicing were generalized to several operands, in line with R6RS.
Commands ,show-known-packages, ,show-interface, and ,show-default-package were added to support SDT (Marcus Crestani, Sebastian Rheinecker).
placeholder-value now accepts a deadlock? argument that says whether blocking on the placeholder contributes to deadlock.
Most source files now carry author information.
A document doc/deriving.txt was added that clarifies how works derived from Scheme 48 should be labelled.
The BIBOP GC was heavily debugged and is now considered stable - it is enabled by default.
The system builds on Windows Visual Studio Express 2010 instead of Visual Studio 2005.
The BIBOP GC code was simplified significantly.
The syntax-rules implementation was rewritten by Richard Kelsey
Some structures were added to the POSIX subsystem (posix-errnos, posix-syslog)
Various procedures were added to the POSIX structures by Roderic Morris to support scsh.
The autoconf code was reorganized by Ivan Shmakov.
The REPL now prints values without quotes and auto-capitalization of record-type names.
The Makefile now builds the documentation upon make install. (This requires a working LaTeX installation and tex2page.) A target install-no-doc is available that does not.
The license information was clarified.
The external-events API was changed to fix a design bug; it now correctly accomodates "fire-once" applications such as wait-for-child-process' (with help from Robert Ransom, Roderic Morris).
Bug fixes