As some of you are aware of Spur added memory pinning and in Pharo 6.1 (#60510) as well as Pharo 7 we currently have Object>>pin Object>>unpin Object>>isPinned and also Object>>setPinned:. Object pinning is explained by Eliot here [1]. I would propose two changes (at least for Pharo but ideally also for Squeak): 1. IMHO #setPinned: should be moved to a private protocol 2. Provide a #pinDuring: aBlock method like: pinDuring: aBlock [ self pin. aBlock value ] ensure: [ self unpin ] so we can ensure that a pinned object is unpinned after an operation. What do you think? Also I wonder why FFICallbackTests>>#testCqsortWithByteArray is sending #pin but not #unpin afterwards. Maybe that is the reason why there is a flag in this method that it is crashing on Windows. Bye T. [1] http://lists.squeakfoundation.org/pipermail/squeak-dev/2017-August/195129.ht...