An external memory system comprising: a memory appliance; and a client device; the client device comprising: a first communication interface; and a local memory comprising: an application logic unit; and a client logic unit; the memory appliance comprising: a processor; a second communication interface; a memory configured in an address space addressable by the processor; and a region access unit; wherein the client logic unit is configured to cause, in response to a memory allocation request, allocation of a region of the memory that is accessible on the memory appliance by the client device through the first communication interface, wherein the region access unit is configured to allocate the region of the memory for use as an external primary memory of the client device on a network, wherein the external primary memory of the client device is primary memory of the client device that is external to the client device and is accessible to the client device over the network via the second communication interface of the memory appliance, wherein the second communication interface is configured to provide the client device access to the region of the memory via client-side memory access before initialization of all of the region, wherein the processor of the memory appliance is bypassed if a client-side memory access request is for an initialized portion of the region of the memory but if the client-side memory access request is for an uninitialized portion of the region, then the processor is configured to initialize the uninitialized portion in response to the client-side memory access request a memory appliance; and a client device; the client device comprising: a first communication interface; and a local memory comprising: an application logic unit; and a client logic unit; a first communication interface; and a local memory comprising: an application logic unit; and a client logic unit; an application logic unit; and a client logic unit; the memory appliance comprising: a processor; a second communication interface; a memory configured in an address space addressable by the processor; and a region access unit; a processor; a second communication interface; a memory configured in an address space addressable by the processor; and a region access unit; wherein the client logic unit is configured to cause, in response to a memory allocation request, allocation of a region of the memory that is accessible on the memory appliance by the client device through the first communication interface, wherein the region access unit is configured to allocate the region of the memory for use as an external primary memory of the client device on a network, wherein the external primary memory of the client device is primary memory of the client device that is external to the client device and is accessible to the client device over the network via the second communication interface of the memory appliance, wherein the second communication interface is configured to provide the client device access to the region of the memory via client-side memory access before initialization of all of the region, wherein the processor of the memory appliance is bypassed if a client-side memory access request is for an initialized portion of the region of the memory but if the client-side memory access request is for an uninitialized portion of the region, then the processor is configured to initialize the uninitialized portion in response to the client-side memory access request