On Oct 24, 2019, at 11:15 AM, Rolf Rabenseifner <[email protected]<mailto:[email protected]>> wrote: For me, it looked like that there was some misunderstanding of the concept that absolute and relative addresses and number of bytes that can be stored in MPI_Aint. ...with the caveat that MPI_Aint -- as it is right now -- does not support modern segmented memory systems (i.e., where you need more than a small number of bits to indicate the segment where the memory lives). I think that changes the conversation entirely, right? -- Jeff Squyres [email protected]<mailto:[email protected]>