Host techniques for stacked memory systems

A system comprising:

• a storage device having a first type of volatile memory and a second type of volatile memory;
• a host device coupled to the storage device, the host device configured to issue commands to the storage device to store and retrieve information of the system;
• wherein the host device includes a memory map of the storage device and latency information associated with each command of the commands;
• wherein the host device is configured to sort pending commands according to the latency information and to intermix commands for the first type of volatile memory and commands for the second type of volatile memory to provide a command schedule and to maintain an efficiency of a data interface between the host device and the storage device greater than 90% as measured from transmission of a first command for the first type of volatile memory to completion of the first command at the storage device;
• and
• wherein a latency of the first command is greater than an accumulated latency of a multiple serially issued commands for the second type of volatile memory.