There are two distinct issues with regards to large arrays. 1) How do you support > 2Gb memory mapped arrays on 32 bit systems and other large-object arrays only a part of which are in memory at any given time (there is an equivalent problem for > 8 Eb (exabytes) on 64 bit systems, an Exabyte is 2^60 bytes or a giga-giga-byte). 2) Supporting the sequence protocol for in-memory objects on 64-bit systems. Part 2 can be fixed using the recommendations Martin is making and which will likely happen (though it could definitely be done faster). Handling part 1 is more difficult. One idea is to define some kind of "super object" that mediates between the large file and the in-memory portion. In other words, the ndarray is an in-memory object, while the super object handles interfacing it with a larger structure. Thoughts? -Travis