System level exploration of a STT-MRAM based level 1 data-cache

Since Non-Volatile Memory (NVM) technologies are being explored extensively nowadays as viable replacements for SRAM based memories in LLCs and even L2 caches, we try to take stock of their potential as level 1 (L1) data caches. These NVMs like Spin Torque Transfer RAM(STT-MRAM), Resistive-RAM(ReRAM) and Phase Change RAM (PRAM) are not subject to leakage problems with technology scaling. They also show significant area gains and lower dynamic power consumption. A direct drop-in replacement of SRAM by NVMs is, however, still not feasible due to a number of shortcomings with latency (write or read) and/or endurance/reliability among them being the major issues. STT-MRAM is increasingly becoming the NVM of choice for high performance and general purpose embedded platforms due to characteristics like low access latency, low power and long lifetime. With advancements in cell technology, and taking into account the stringent reliability and performance requirements for advanced technology nodes, the major bottleneck to the use of STT-MRAM in high level caches has become read latency (instead of write latency as previously believed). The main focus of this paper is the exploration of read penalty issues in a NVM based L1 data cache (D-cache) for an ARM like single core general purpose system. We propose a design method for the STT-MRAM based D-cache in such a platform. This design addresses the adverse effects due to the STT-MRAM read penalty issues by means of micro-architectural modifications along with code transformations. According to our simulations, the appropriate tuning of selective architecture parameters in our proposal and suitable optimizations can reduce the performance penalty introduced by the NVM (initially ~54%) to extremely tolerable levels (~8%).Ministerio de Ciencia e Innovación de EspañaIMECDepto. de Arquitectura de Computadores y AutomáticaFac. de InformáticaTRUEpu

Dynamic mechanical analysis of binary and ternary polymer blends based on nylon copolymer/EPDM rubber and EPM grafted maleic anhydride compatibilizer

The dynamic mechanical properties such as storage modulus, loss modulus and damping properties of blends of nylon copolymer (PA6,66) with ethylene propylene diene (EPDM) rubber was investigated with special reference to the effect of blend ratio and compatibilisation over a temperature range –100°C to 150°C at different frequencies. The effect of change in the composition of the polymer blends on tanδ was studied to understand the extent of polymer miscibility and damping characteristics. The loss tangent curve of the blends exhibited two transition peaks, corresponding to the glass transition temperature (Tg) of individual components indicating incompatibility of the blend systems. The morphology of the blends has been examined by using scanning electron microscopy. The Arrhenius relationship was used to calculate the activation energy for the glass transition of the blends. Finally, attempts have been made to compare the experimental data with theoretical models.Cochin University of Science and Technology,S.N.M College, NIT Calicut,Central Power Research Institute,M.G Universit

Carboxymethylcellulose hybrid nanodispersions for edible coatings with potential anti-cancer properties

Curcumin loaded lipid-polymer hybrid nanoparticles dispersions were fabricated from carboxymethylcellulose, stearic acid, polyethylene glycol and sesame oil using emulsion solvent evaporation method for their possible application as edible coatings for fresh vegetables and fruits. They were characterized by FTIR and TEM analysis. In addition, anti-bacterial, blood compatibility, cytotoxicity and anticancer studies were also carried out. The prepared nanodispersions showed excellent mixed nanostructured morphology with an average size of 94.96 nm. The hybrid nanodispersions showed excellent blood compatibility, non-toxicity and antitumor activity. The synthesized nanoparticle dispersion was employed as an edible coating solution for fresh apples and tomatoes. The hybrid system coated vegetables and fruits shows minimal weight loss after 15 days of storage. Hence, the formulated hybrid nanostructures of CMC are promising as edible coating solution, in addition to possessing the properties to fight cancer.Scopu

Main memory organization trade-offs with DRAM and STT-MRAM options based on gem5-NVMain simulation frameworks

Current main memory organizations in embedded and mobile application systems are DRAM dominated. The ever-increasing gap between today's processor and memory speeds makes the DRAM subsystem design a major aspect of computer system design. However, the limitations to DRAM scaling and other challenges like refresh provide undesired trade-offs between performance, energy and area to be made by architecture designers. Several emerging NVM options are being explored to at least partly remedy this but today it is very hard to assess the viability of these proposals because the simulations are not fully based on realistic assumptions on the NVM memory technologies and on the system architecture level. In this paper, we propose to use realistic, calibrated STT-MRAM models and a well calibrated cross-layer simulation and exploration framework, named SEAT, to better consider technologies aspects and architecture constraints. We will focus on general purpose/mobile SoC multi-core architectures. We will highlight results for a number of relevant benchmarks, representatives of numerous applications based on actual system architecture. The most energy efficient STT-MRAM based main memory proposal provides an average energy consumption reduction of 27% at the cost of 2x the area and the least energy efficient STT-MRAM based main memory proposal provides an average energy consumption reduction of 8% at the around the same area or lesser when compared to DRAM.Ministerio de Ciencia e Innovación de EspañaIMECDepto. de Arquitectura de Computadores y AutomáticaFac. de InformáticaTRUEpu