MESI protocol for multicore processors based on FPGA

In modern techniques of building processors, manufactures using more than one processor in the integrated circuit (chip) and each processor called a core. The new chips of processors called a multi-core processor. This new design makes the processors to work simultaneously for more than one task or all the cores working in parallel for the same task. All cores are similar in their design, and each core has its own cache memory, while all cores shares the same main memory. So, if one core requests a block of data from main memory to its cache, there should be a protocol to declare the situation of this block in the main memory and other cores. This is called the cache coherency or cache consistency of multi-core. In this paper a special circuit is designed using VHDL coding and implemented using ISE Xilinx software, one protocol was used in this design, the MESI (Modify, Exclusive, Shared and Invalid) protocol. Test results were taken by using test bench, and showed all the states of the protocols are working correctly

Study of effective calculation operation implementation remaining multi-bit numbers division on FPGA

The rapid enhanced in the fields of the computers that leads to rapid breaking for ciphering algorithms and for these reasons most of ciphering algorithm tried to used multidigit for ciphering texts or images. Using the multidigit will increase the safety of information and protected it from supercomputer from breaking the ciphering algorithms. The current information systems employ operations on finite fields of various structures (for example, cryptographic systems). In this instance, it's common to have to deal with enormous numbers (128 bits or more). The proposed operation of discovering the remainder of the division of multidigit numbers will considerably improve the speed of such systems if implemented

Ionospheric Disturbance Dynamo Associated to coronal hole during Geomagnetic Storm 1-5 August 2002

International audienceIn this paper we study the ionosphericmagnetic disturbance during a magnetic storm on 2 August 2002 associated to a coronal hole. The Earth was under the influence of a high speed solar wind and IMF was southward. We separate the magnetic disturbance associated to the ionospheric disturbance dynamo (Ddyn) from the magnetic disturbance associated to the prompt penetration of magnetospheric electric field (DP2).We used three Stations (AAE, GUA and HUA) from INTERMAGNET Magnetometers in the equatorial regions at different longitude sectors (African, Asian and American respectively). At the beginning of the storm our data highlights the effect of the prompt penetration of the magnetosphere electric field (DP2). During the recovery phase of the storm, we observe the signature of ionospheric disturbance dynamo due to wind produced by Joule heating in the auroral zone. It is the first time that we observe an anti-Sq circulation on magnetic data in agreement with the Blanc and Richmonds model of ionospheric disturbance dynamo. The strongest effect is observed in the American secto

Etudes de l'Ionosphère Equatoriale dans le cadre du réseau GIRGEA (Groupe International de Recherche en Géophysique Europe Afrique)

International audienceRésumé: Durant la dernière décennie dans le cadre des projets CAWSES (Climate and Weather in the Sun Earth System), AHI (Année Héliophysique Internationale) 2006-2009 et ISWI (International Space Weather Initiative) 2010-2012, la connaissance du soleil et de son impact sur les couches ionisées a considérablement avancé suivant différents canaux : - synthèse connectant la physique du soleil à celle de lionosphère - analyse de longues séries de données ionosphériques sur plusieurs cycles solaires - déploiement dinstruments (GPS et magnétomètres) sur le continent africain dans des régions où les mesures étaient inexistantes, ce fait entrainant la révision de certains modèles. Le réseau de recherche GIRGEA a profité de ces projets et développé des études des zones équatoriales en Afrique et en Asie. Cet article présente les résultats obtenus concernant principalement les variations long terme de lIonosphère équatoriale, limpact des éjections de masse coronale et des jets de vents rapides issus des trous coronaux sur les couches ionisés, et linadéquation de certains modèles à représenter les récentes observations en Afrique

Study of the Equatorial Ionosphere in the research network GIRGEA

International audienc