LispWorks supports "lightweight" processes. The programming environment, for example, makes extensive use of this mechanism to create separate processes for the various tools.
On Microsoft Windows, Mac OS X, Linux, x86/x64 Solaris and FreeBSD, LispWorks multiprocessing uses native threads and supports Symmetric Multiprocessing (SMP). The implementation is referred to as "SMP LispWorks" where relevant.
On other platforms LispWorks uses a single native thread and implements user level threads. The implementation is referred to as "non-SMP LispWorks" where relevant.