SBCL descends from
CMUCL (created at
Carnegie Mellon University), which is itself descended from
Spice Lisp, including early implementations for the
Mach operating system on the
IBM RT PC, and the Three Rivers Computing Corporation
PERQ computer, in the 1980s. William Newman originally announced SBCL as a variant of CMUCL in December 1999. The main point of divergence at the time was a clean
bootstrapping procedure: CMUCL requires an already compiled
executable binary of itself to compile the CMUCL source code, whereas SBCL supported bootstrapping from theoretically any
ANSI-compliant Common Lisp implementation. SBCL became a
SourceForge project in September 2000. The original rationale for the
fork was to continue the initial work done by Newman without destabilizing CMUCL which was at the time already a mature and much-used implementation. The forking was amicable, and there have since then been significant flows of code and other cross-pollination between the two projects. Since then SBCL has attracted several developers, been ported to multiple hardware architectures and operating systems, and undergone many changes and enhancements: while it has dropped support for several CMUCL extensions that it considers beyond the scope of the project (such as the
Motif interface) it has also developed many new ones, including native threading and Unicode support. Version 1.0 was released in November 2006, and active development continues. William Newman stepped down as project administrator for SBCL in April 2008. Several other developers have taken over interim management of releases for the time being. For the tenth anniversary of SBCL, a Workshop was organized. Version 2.0.0 was released on 29 December 2019 for the 20th anniversary of SBCL, with no major breaking changes. ==References==