Hello, Major news: NativeBoost now working on Macs! The main problem with Mac OS platform was that it requires a stack alignment discipline, while other platforms don't. So, i had to extend the assembler to make sure that all external calls will be made with properly aligned stack. Also, i spent time to improve error handling. Since in Cog/Stack VMs we having nice primitive error code, now it can report what caused a failure in more detail, than just failing a primitive and leaving a language side to guess what gone wrong. There's a lot of other small changes, like new tests, more examples etc.. But i don't want to describe them all (and frankly i don't remember all of them ;) Things not yet working: The callbacks to language side is not functional (i have to revise this code to synchronize it with callback machinery in Cog VMs). The callbacks to native code working well (of course, because it don't needs to deal with VM-specific stuff ;) The prebuilt VMs, which contain a NativeBoost plugin are now on Jenkins server. These VMs will be built automatically each time there is code update for Cog VMs (in same way as all continuous integration jobs). The only difference between original Cog VMs and Cog+NativeBoost VMs is that they contain NativeBoost plugin. So, you can use these VMs instead of Cog VMs if you like. You can download VMs from here: https://ci.lille.inria.fr/pharo/view/NativeBoost/ To install NativeBoost into your image follow instructions on: http://code.google.com/p/nativeboost/wiki/Installation -- Best regards, Igor Stasenko AKA sig.