Wimp2 is an alternative multitasker for Acorn RISCOS which preemptively multitasks the application rather than cooperatively as the current RISCOS Wimp does. It also provide various kernel enhancements such as a 1ms resolution interrupt timer. Wimp2 is designed to be broadly compatible with the existing application structure used by RISCOS. The only difference is that the 17, 18 & 19 codes handler must be placed in a separate nonpreempted routine so that Wimp messages requiring an immediate answer are not returned as unanswered by the Wimp through a code 19. There are facilities to have the message passed into the normal message queue or have preemption halted until the main queue deals with the message. Wimp2 is compatible with all versions of RISCOS from v2 to the upcoming v4. It also handles correctly sprite redirection and floatingpoint register use. Also supplied are the full sources for Wimp2 so that you can see how it works yourself, and if you want, modify or enhance it. Wimp2 correctly preempts assembler, C and Basic code. There is also basic multithreading support built into the code, although this is not implemented at this time. In addition, Wimp2 replaces some filing system calls with ones that can be preemptively multitasked so now long disc operations dont halt multitasking If you want to know more, try downloading it and giving it a go

Website: http://www.nedprod.com/programs/RISCOS/Wimp2/