Scalable Cache Coherence Protocols Are Essential For Multiprocessor Systems

Partitioning strategy: The hierarchical partitioning of data into a set of directories – The placement and replication properties of directories is

Server state can be divided into two part : the stateful and stateless server. The stateful server is that when a client open a file the server gives that client an unique identifier and stores client’s information into its memory. Although this method can improve performance, however, stateful server is generally be avoided in distributed system. On the other hand, stateless server uses totally different mechanism that the server identifies the file information and client position in each request but save nothing into its memory. The advantage is that it is easier to use fault tolerance on stateless server.

Blocks are the logical records which breaks the area used by a partition; clusters are physical bodies of a hard disk. Hard disk is usually broken in to cylinders and cylinders are broken down in to clusters. Most HDD arrive from the factory with a low level pattern where, block size = 512 bytes. The NTFS file system can produce cluster sizes of a multiple of 512 having a default of 8 blocks for every cluster. Size of a block is multiple of size of cluster, such that a logical block will fit a definite number of physical clusters “one file one cluster”. That is, in every cluster will be installed information belonging at most to a single file. As an aftermath, when scripting a file in a hard disk, some cluster remains incompletely filled or fully unused. As the operating system can only write an entire block, it pursues that the idle space should be fit with some strings of bytes that can be used by others. It should be remembered that these data are saved in a disk because of the operating system curbs to write only on an entire block, they could be detected by locating

Memory segmentation is the division of a computer's primary memory information into sections. Segments are applied in object records of compiled programs when linked together into a program image and when the image is loaded into the memory. Segmentation sights a logical address as a collection of segments. Each segment has a name and length. With the addresses specifying both the segment name and the offset within the segment. Therefore the user specifies each address by two quantities: a segment name and an offset. When compared to the paging scheme, the user specifies a single address, which is partitioned by the hardware into a page number and an offset, all invisible to the programmer. Memory segmentation is more visible

Since the invention of the first computer, engineers have been conceptualizing and implementing ways to optimize system performance. The last 25 years have seen a rapid evolution of many of these concepts, particularly cache memory, virtual memory, pipelining, and reduced set instruction computing (RISC). Individual each one of these concepts has helped to increase speed and efficiency thus enhancing overall system performance. Most systems today make use of many, if not all of these concepts. Arguments can be made to support the importance of any one of these concepts over one

CC met with the member and introduce herself to the member as his new care coordinator. The member report that he would like to schedule another appointment to do his treatment plan because he want to get home and take his medication. CC schedule the member to on Thursday, 2/4/2016 at 10:00am. The member states that the doctor change all of his medication because they were not working for him. The member was unable to sit still and keep getting up and walking around stating he want to go home and try his new medication to see if they will work for him. The member was unable to stay focus and keep talking because the voices keep talking to him and he did not want to hear what the voices had to say. The member states that the voices tell

Abstract – Many multiprocessor chips and computer systems today have hardware that supports shared-memory. This is because shared-memory multicore chips are considered a cost-effective way of providing increased and improved computing speed and power since they utilize economically interconnected low-cost microprocessors. Shared-memory multiprocessors utilize cache to reduce memory access latency and significantly reduce bandwidth needs for the global interconnect and local memory module. However, a problem still exists in these systems: cache coherence problem introduced by local caching of data, which leads to reduced processor execution speeds. The problem of cache coherence in hardware is reduced in today’s microprocessors through the implementation of various cache coherence protocols. This article reviews literature on cache coherence with particular attention to cache coherence problem, and the protocols-both hardware and software that have been proposed to solve it. Most importantly, it identifies a specific problem associated with cache coherence and proposes a novel solution.

-Each mapped page uses the file itself as a backing store. Unmapped memory uses a scratch file or partition as backing store.

In this report the author provides quantifiable results that show the available parallelism. The report defines various terminologies like Instruction Level parallelism, dependencies, Branch Prediction, Data Cache Latency, Jump prediction, Memory-address alias analysis etc. used clearly. A total of eighteen test programs with seven models have been examined and the results show significant effects of the variations on the standard models. The seven models reflect parallelism that is available by various compiler/architecture techniques like branch prediction, register renaming etc. The lack of branch prediction means that it finds intra-block

The tremendous increase of system concurrency from hundreds of thousands to hundreds of millions will be a big challenge for system software to manage and for applications to get good performance at this level of parallelism. As we all know that almost all of today’s large-scale applications use the message-passing programming model (MPI) together with traditional sequential languages (C, Fortran, C++), but the new architectures with many cores per chip and parallelism in the millions will make this programming model more problematic and less productive in the future. Thus a new approach is needed. Like

3. Consider a distributed file system that does client caching using write through. The system caches individual blocks, rather than entire files. Can the client in this system have a cache consistency problem? If so, suggest two possible solutions.

The Linux file system is ordered in a structured hierarchically tree. This file system is a tree shaped structure, where the root of the tree is called the file system root and beneath the root are directories. The root of the file system is usually stored on the partition of a disk and combing one partition with the file system is known as mounting a file system. …….. The Linux architecture handles all of the types of files by hiding the implementation details of any single file type behind a certain layer of software, which is called the VFS or virtual file system. The standard file system that is on-disk is called ext3. The ext3 file system is partitioned into multiple segments that are termed block groups. Ext3 first selects the block group for the file when it starts allocating. Within each block group it tries to keep allocations physically contiguous and reduces fragmentation if possible. It also maintain a bitmap of all free blocks within a certain block group. Whenever a free block is identified, the search is extended backwards until an allocated block is found.

Abstract: Hashing is the convenient way to get access to an item based on the given key which is the requirement for efficient buffer cache management. Static hashing provides fastest access to an object at the cost of memory utilization, whereas sequential storage provides most efficient memory utilization at the cost of access time. To provide balance between two extremes dynamic hashing schemes are produced. The focus of this paper is to survey various dynamic hashing schemes with perspective to use it in database buffer cache management. It includes dynamic hashing techniques like Extendible hashing, Expandable Hashing, Spiral Storage, Linear

HPC (high performance computing) frameworks are based on both software and hardware platforms. The mechanism called fault tolerance is nothing but process which allows system (frequently software based) to continue working properly in case of failure of its components (one or more faults) on MPI (message passing interface). In HPC systems like grid computing, cloud computing etc. fault tolerance method highly applicable in order to ensure that long operating applications are finished their tasks according to time. Therefore, there are different types of fault tolerance methods introduced in literature.

In this paper, you 'll learn precisely what virtual storage is, what your pc uses it for and the way to piece it on your own machine to realize optimum performance.