Distributed shared memories (DSM) allow processes to share memory objects even when they execute in environments such as workstation cluster where shared memory is not provided by the the hardware. We have implemented Indigo, a user-level library which can be used to implement several types of distributed memory systems. We have already implemented a DSM that exploits weak consistency and synchronization information to provide high performance memory objects. Both Indigo and the DSM systems currently run on Sun and SGI workstation clusters as well as on the IBM SP-2 machine. We have developed several novel techniques to improve performance of memory objects. For example, we have developed a scheme for handling false sharing that incurs additional overhead only when false sharing is actually present.