Letter from the Special Issue Editor

Editorial work for DEBULL on a special issue on data management on Storage Class Memory (SCM) technologies

異種の不揮発性メモリで構成される半導体ストレージシステムに関する研究

【学位授与の要件】中央大学学位規則第4条第1項【論文審査委員主査】竹内　健　（中央大学理工学部教授）【論文審査委員副査】山村　清隆（中央大学理工学部教授）、築山　修治（中央大学理工学部教授）、首藤　一幸（東京工業大学大学院情報理工学研究科准教授）博士（工学）中央大

Sulautettujen suorittimien muistityypit

Tiivistelmä. Tässä kirjallisuuskatsauksessa tutustutaan sulautettujen suorittimien muistityyppeihin. Muistiteknologioiden nopea kehittyminen viime vuosina on tuonut perinteisesti sulautetuissa suorittimissa käytettyjen muistityyppien rinnalle myös uusia ratkaisuja. Ferrosähköinen muisti (FRAM) ja faasimuutokseen perustuva muisti (PRAM) edustavat tässä työssä uusia, jo kaupallistettuja muistityyppejä. Sulautettujen järjestelmien suunnittelussa energiankulutus on keskeinen kriteeri. Niinpä muistityyppien ominaisuuksia tarkastellaan ja muistityyppejä vertaillaan keskenään ennen muuta energiankulutuksen näkökulmasta. Lopuksi tutustutaan kahteen mikro-ohjaimeen, joissa käytetään eri muistityypeistä koostuvia muistikonfiguraatioita. Tämän kirjallisuuskatsauksen perusteella voidaan todeta, että korvaamalla nykyisissä mikro-ohjaimissa yleisimmin haihtumattomana muistina käytetty flashmuisti ferromagneettisella muistilla (FRAM), voitaisiin saavuttaa energiatehokkaampi ja erityisesti langattomiin IoT-sovelluksiin paremmin soveltuva muistiratkaisu. FRAM soveltuisi yksinään käytettäväksi yhdistettynä käsky- ja datamuistina esim. energiankeruusovelluksissa. Vaikka sulautettu muisti voidaan toteuttaa pelkällä FRAM:lla, tarjoaa SRAM:iin ja FRAM:iin perustuva muistikonfiguraatio kuitenkin energiatehokkaamman ratkaisun, jonka energiankulutusta voidaan edelleen pienentää tehokkaalla muistiviittausten optimoinnilla.Memory types of the embedded memory. Abstract. The memory types used as embedded memory in microcontrollers are discussed in this literature review. There has been a rapid technical development in the area of the memory technologies during the last few years. As a result, it has emerged some new memory types that have been used in the memory configurations of the microcontrollers in parallel with more traditional memory types. The ferromagnetic memory (FRAM) and phase change memory (PRAM) are in the scope of the review. The properties of the memory types are specially considered from the perspective of energy consumption. Finally, two widely used microcontrollers representing two different memory configurations are discussed as examples of embedded memory types. On the basis of this literature review, it seems that the replacement of the flash as a non-volatile memory by the ferromagnetic memory (FRAM) makes sense from the perspective of energy consumption. FRAM can also be implemented as unified memory which makes it a very attractive memory type for the IoT and energy-harvesting applications too. However, the memory configuration based on SRAM and FRAM is more energy efficient. The energy efficiency of SRAM-FRAM hybrid configuration can be further increased by optimizing the memory access routines

Extending Memory Capacity in Consumer Devices with Emerging Non-Volatile Memory: An Experimental Study

The number and diversity of consumer devices are growing rapidly, alongside their target applications' memory consumption. Unfortunately, DRAM scalability is becoming a limiting factor to the available memory capacity in consumer devices. As a potential solution, manufacturers have introduced emerging non-volatile memories (NVMs) into the market, which can be used to increase the memory capacity of consumer devices by augmenting or replacing DRAM. Since entirely replacing DRAM with NVM in consumer devices imposes large system integration and design challenges, recent works propose extending the total main memory space available to applications by using NVM as swap space for DRAM. However, no prior work analyzes the implications of enabling a real NVM-based swap space in real consumer devices. In this work, we provide the first analysis of the impact of extending the main memory space of consumer devices using off-the-shelf NVMs. We extensively examine system performance and energy consumption when the NVM device is used as swap space for DRAM main memory to effectively extend the main memory capacity. For our analyses, we equip real web-based Chromebook computers with the Intel Optane SSD, which is a state-of-the-art low-latency NVM-based SSD device. We compare the performance and energy consumption of interactive workloads running on our Chromebook with NVM-based swap space, where the Intel Optane SSD capacity is used as swap space to extend main memory capacity, against two state-of-the-art systems: (i) a baseline system with double the amount of DRAM than the system with the NVM-based swap space; and (ii) a system where the Intel Optane SSD is naively replaced with a state-of-the-art (yet slower) off-the-shelf NAND-flash-based SSD, which we use as a swap space of equivalent size as the NVM-based swap space

Status of phase change memory in memory hierarchy and its impact on relational database

Master'sMASTER OF SCIENC