Byte-addressable persistent RAM APIs for flexible memory management and protection

Abstract

Byte-addressable persistent random access memory (BPRAM) provides uninterruptable computing experience at power loss. Since there is no need of power to store the data, it is possible to provide faster booting time from completely off-state by utilizing BPRAM as the main memory. However, there is still no explicit explanation about the BPRAM application programming interfaces (APIs) specification taking benefit of the persistent characteristic of the memory. Providing APIs at the operating system level will open possibility to the application and operating system developers to utilize persistent memory to its extent. We defined APIs specifications which include memory management and protection, as some application should not be abusing the BPRAM of its limited lifetime. We focused on phase-change memory (PCM) as the representation of BPRAM, since it is the most probable candidate for DRAM replacement. We observed there are room for improvements to elongate BPRAM lifetime, such as the shared library objects loading to the BPRAM, separation of three memory region in process (i.e. code, data, stack regions), moving rarely modified blocks of RAM to the BPRAM, and also the capability of saving only important states when desired. © 2013 Springer Science+Business Media.