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Adaptive Replacement Cache
Adaptive Replacement Cache (ARC) is a page replacement algorithm with better performance than LRU (least recently used). This is accomplished by keeping track of both frequently used and recently used pages plus a recent eviction history for both. The algorithm was developed at the IBM Almaden Research Center. In 2006, IBM was granted patent for the adaptive replacement cache policy Summary Basic LRU maintains an ordered list (the cache directory) of resource entries in the cache, with the sort order based on the time of most recent access. New entries are added at the top of the list, after the bottom entry has been evicted. Cache hits move to the top, pushing all other entries down. ARC improves the basic LRU strategy by splitting the cache directory into two lists, T1 and T2, for recently and frequently referenced entries. In turn, each of these is extended with a ''ghost'' list (B1 or B2), which is attached to the bottom of the two lists. These ''ghost'' lists act as sc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Page Replacement Algorithm
In a computer operating system that uses paging for virtual memory management, page replacement algorithms decide which memory pages to page out, sometimes called swap out, or write to disk, when a page of memory needs to be allocated. Page replacement happens when a requested page is not in memory (page fault) and a free page cannot be used to satisfy the allocation, either because there are none, or because the number of free pages is lower than some threshold. When the page that was selected for replacement and paged out is referenced again it has to be paged in (read in from disk), and this involves waiting for I/O completion. This determines the ''quality'' of the page replacement algorithm: the less time waiting for page-ins, the better the algorithm. A page replacement algorithm looks at the limited information about accesses to the pages provided by hardware, and tries to guess which pages should be replaced to minimize the total number of page misses, while balancing thi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cache Algorithms
In computing, cache algorithms (also frequently called cache replacement algorithms or cache replacement policies) are optimizing instructions, or algorithms, that a computer program or a hardware-maintained structure can utilize in order to manage a cache of information stored on the computer. Caching improves performance by keeping recent or often-used data items in memory locations that are faster or computationally cheaper to access than normal memory stores. When the cache is full, the algorithm must choose which items to discard to make room for the new ones. Overview The average memory reference time is : T = m \times T_m + T_h + E where : m = miss ratio = 1 - (hit ratio) : T_m = time to make a main memory access when there is a miss (or, with multi-level cache, average memory reference time for the next-lower cache) : T_h= the latency: the time to reference the cache (should be the same for hits and misses) : E = various secondary effects, such as queuing effects in mult ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nimrod Megiddo
, birth_date = , birth_place = , death_date = , death_place = , citizenship = , field = Operations researchAlgorithms ComplexityMachine learning Game theory , workplaces = IBM Research Stanford University , alma_mater = Hebrew University of Jerusalem , thesis_title = Compositions of Cooperative Games , thesis_year = 1972 , doctoral_advisor = Michael Maschler , doctoral_students =Edith Cohen , known_for = Prune and search , prizes = Frederick W. Lanchester Prize (1992)John von Neumann Theory Prize (2014) , website = Nimrod Megiddo ( he, נמרוד מגידו) is a mathematician and computer scientist. He is a research scientist at the IBM Almaden Research Center and Stanford University. His interests include combinatorial optimization, algorithm design and analysis, game theory, and machine learning. He was one of the first people to propose a solution to the bounding sphe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dharmendra Modha
__NOTOC__ Dharmendra S. Modha is an Indian American manager and lead researcher of the Cognitive Computing group at IBM Almaden Research Center. He is known for his pioneering works in Artificial Intelligence and Mind Simulation. In November 2009, Modha announced at a supercomputing conference that his team had written a program that simulated a cat brain. He is the recipient of multiple honors, including the Gordon Bell Prize, given each year to recognize outstanding achievement in high-performance computing applications. In November 2012, Modha announced on his blog that using 96 Blue Gene/Q racks of the Lawrence Livermore National Laboratory Sequoia supercomputer (1,572,864 processor cores, 1.5 PB memory, 98,304 MPI processes, and 6,291,456 threads), a combined IBM and LBNL team achieved an unprecedented scale of 2.084 billion neurosynaptic cores containing 530 billion neurons and 137 trillion synapses running only 1542× slower than real time. In August 2014 a paper describing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Almaden Research Center
IBM Research is the research and development division for IBM, an American multinational information technology company headquartered in Armonk, New York, with operations in over 170 countries. IBM Research is the largest industrial research organization in the world and has twelve labs on six continents. IBM employees have garnered six Nobel Prizes, six Turing Awards, 20 inductees into the U.S. National Inventors Hall of Fame, 19 National Medals of Technology, five National Medals of Science and three Kavli Prizes. , the company has generated more patents than any other business in each of 25 consecutive years, which is a record. History The roots of today's IBM Research began with the 1945 opening of the Watson Scientific Computing Laboratory at Columbia University. This was the first IBM laboratory devoted to pure science and later expanded into additional IBM Research locations in Westchester County, New York, starting in the 1950s,Beatty, Jack, (editor''Colussus: how th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IBM DS8000
The IBM DS8000 series (early IBM System Storage DS8000 series) is an IBM storage media platform with hybrid flash and hard disk storage for IBM mainframes and other enterprise grade computing environments. Description This series formerly designed as line of cabinet-size solutions, prior to more compact and affordable rack-mount DS6000 series. In 2015 the DS6000 line were discontinued, and the all-flash entry-level DS8882F model was released as rack-mount successor of DS6000 line. All IBM DS storage lines based on a IBM Power CPUs and use an IBM Power Systems servers as controllers. Models * TotalStorage models: ** DS8100 - released in 2004 *** Dual 2-core POWER5+-based controllers *** Can contain up to 384 drives (Fibre Channel or SATA) ** DS8300 - released in 2004 *** Dual 4-core POWER5+-based controllers (based on p570 servers) *** Can contain up to 1024 drives (Fibre Channel or SATA) * System Storage models: **DS8100 Turbo - released in 2006 **DS8300 Turbo - release ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sun Microsystems
Sun Microsystems, Inc. (Sun for short) was an American technology company that sold computers, computer components, software, and information technology services and created the Java programming language, the Solaris operating system, ZFS, the Network File System (NFS), and SPARC microprocessors. Sun contributed significantly to the evolution of several key computing technologies, among them Unix, RISC processors, thin client computing, and virtualized computing. Notable Sun acquisitions include Cray Business Systems Division, Storagetek, and ''Innotek GmbH'', creators of VirtualBox. Sun was founded on February 24, 1982. At its height, the Sun headquarters were in Santa Clara, California (part of Silicon Valley), on the former west campus of the Agnews Developmental Center. Sun products included computer servers and workstations built on its own RISC-based SPARC processor architecture, as well as on x86-based AMD Opteron and Intel Xeon processors. Sun also develope ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solaris (operating System)
Solaris is a proprietary Unix operating system originally developed by Sun Microsystems. After the Sun acquisition by Oracle in 2010, it was renamed Oracle Solaris. Solaris superseded the company's earlier SunOS in 1993, and became known for its scalability, especially on SPARC systems, and for originating many innovative features such as DTrace, ZFS and Time Slider. Solaris supports SPARC and x86-64 workstations and servers from Oracle and other vendors. Solaris was registered as compliant with the Single UNIX Specification until 29 April 2019. Historically, Solaris was developed as proprietary software. In June 2005, Sun Microsystems released most of the codebase under the CDDL license, and founded the OpenSolaris open-source project. With OpenSolaris, Sun wanted to build a developer and user community around the software. After the acquisition of Sun Microsystems in January 2010, Oracle decided to discontinue the OpenSolaris distribution and the development mode ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PostgreSQL
PostgreSQL (, ), also known as Postgres, is a free and open-source relational database management system (RDBMS) emphasizing extensibility and SQL compliance. It was originally named POSTGRES, referring to its origins as a successor to the Ingres database developed at the University of California, Berkeley. In 1996, the project was renamed to PostgreSQL to reflect its support for SQL. After a review in 2007, the development team decided to keep the name PostgreSQL and the alias Postgres. PostgreSQL features transactions with Atomicity, Consistency, Isolation, Durability (ACID) properties, automatically updatable views, materialized views, triggers, foreign keys, and stored procedures. It is designed to handle a range of workloads, from single machines to data warehouses or Web services with many concurrent users. It is the default database for macOS Server and is also available for Windows, Linux, FreeBSD, and OpenBSD. History PostgreSQL evolved from the Ing ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
VMware
VMware, Inc. is an American cloud computing and virtualization technology company with headquarters in Palo Alto, California. VMware was the first commercially successful company to virtualize the x86 architecture. VMware's desktop software runs on Microsoft Windows, Linux, and macOS. VMware ESXi, its enterprise software hypervisor, is an operating system that runs on server hardware. In May 2022, Broadcom Inc. announced an agreement to acquire VMware in a cash-and-stock transaction valued at $61 billion. History Early history In 1998, VMware was founded by Diane Greene, Mendel Rosenblum, Scott Devine, Ellen Wang and Edouard Bugnion. Greene and Rosenblum were both graduate students at the University of California, Berkeley. Edouard Bugnion remained the chief architect and CTO of VMware until 2005, and went on to found Nuova Systems (now part of Cisco). For the first year, VMware operated in stealth mode, with roughly 20 employees by the end of 1998. The company wa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
OpenZFS
OpenZFS is a free and open-source storage platform licensed under CDDL that encompasses the functionality of traditional filesystems and logical volume manager. It includes protection against data corruption, support for high storage capacities, efficient data compression, snapshots and copy-on-write clones, continuous integrity checking and automatic repair, encryption, remote replication with ZFS send and receive, and RAID-Z. The OpenZFS project brings together developers from the illumos, Linux, FreeBSD and macOS platforms, and a wide range of companies via the annual OpenZFS Developer Summit. Founding members of OpenZFS include Matt Ahrens, one of the main architects of ZFS. The OpenZFS project is an open source derivative of the Oracle ZFS project. , OpenZFS (on some platforms such as FreeBSD) is gradually being pivoted to be based upon ZFS on Linux, which has developed faster than other variants of OpenZFS and contains new features not yet ported to those other versi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multi-level Cache
A CPU cache is a hardware cache used by the central processing unit (CPU) of a computer to reduce the average cost (time or energy) to access data from the main memory. A cache is a smaller, faster memory, located closer to a processor core, which stores copies of the data from frequently used main memory locations. Most CPUs have a hierarchy of multiple cache levels (L1, L2, often L3, and rarely even L4), with different instruction-specific and data-specific caches at level 1. The cache memory is typically implemented with static random-access memory (SRAM), in modern CPUs by far the largest part of them by chip area, but SRAM is not always used for all levels (of I- or D-cache), or even any level, sometimes some latter or all levels are implemented with eDRAM. Other types of caches exist (that are not counted towards the "cache size" of the most important caches mentioned above), such as the translation lookaside buffer (TLB) which is part of the memory management unit (MMU) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
