Various embodiments of the present invention provide distributed computing systems featuring an operating-system-transparent distributed memory that, among other things, facilitates shared-message-based inter-thread communication between intercommunicating threads executing concurrently on a single-processor computer system, concurrently and simultaneously on a multi-processor computer system, and concurrently and simultaneously on multiple, discrete computer systems. Certain embodiments of the present invention are implemented using a secure-platform architecture in which secure-platform code running on processors within a distributed computing system provide a virtual, or logical, computing platform on which operating systems and higher-level software can be layered. A distributed memory system is provided by the secure-platform layer, using an extension of the memory-management hardware, firmware, and software systems originally developed to support virtual memory in single-processor and multi-processor computer systems. In essence, logical processors, logical caches, logical memory, and logical mass-storage-device-implemented backing store are mapped onto the individual processors, caches, memories, and interconnected mass-storage systems of a number of discrete computer systems interconnected by high-speed networking.