The term RAID was coined in 1987 as an acronym for Redundant Array of Inexpensive Disks; a computer storage technology that was first described by researchers David Patterson, Garth Gibson and Randy Katz at the University of California, Berkley. The concept proposed that an increase in I/O performance and storage reliability could be obtained by arranging several low-cost disk drives into arrays. Several different schemes of organizing the data across the array emerged and were described by the word RAID followed by a single number. Each of these RAID levels has associated advantages and disadvantages however they all share the same primary characteristic in which the data is distributed across multiple disks and seen by the host computer as a single disk. There are three key concepts in RAID technology; mirroring, which writes the same data to more than one disk; stripping, which splits the data across more than one disk; and error correction, where redundant or ‘parity’ data is stored to allow errors in the array to be detected and fixed. Each of the individual RAID levels implements one or more of these concepts to increased I/O performance and improved data reliability. However, it is difficult for researches to design a RAID level that will meet all three and therefore there are tradeoffs when selecting a level for your RAID array. Each of the standard RAID schemes can have positive and negative affects on the reliability and performance of the array; mirroring, can speed up the reading of data but will be slow to write data since the data must be written to the entire mirrored disks. RAID 0 stripes the data across multiple disks without parity or mirroring; resulting in improved read/write performance and space efficiency... ... middle of paper ... ...tripe units can be read simultaneously; however, the write performance takes a hit as the parity stripe has to be recalculated when new data is written. RAID 5 is mainly used for applications requiring decent data redundancy and very good read performance such as the data drives of highly available server systems. RAID 6 expands on the strengths of RAID 5 by striping the data across multiple disks with dual distributed parity; resulting in excellent fault tolerance and data availability. Traditionally a single parity RAID array is vulnerable to data loss until the failed drive is replaced and the array is rebuilt. By making use of dual distributed parity stripe units RAID 6 is able to survive dual drive failures. Due to its similarity to RAID 5, RAID 6 is used in similar applications but where an extra level of data redundancy and fault tolerance is required.
Hard Disk Drive (HDD) - Hard drives can store very large amounts of data ranging from 200GB – 1TB. A hard drive is made up of a magnetic disk that consists of a number of platters/disks that are coated in a magnetic material that rotate at 7200 RPM. The data is encoded into bits and written into the disks as a series of changes in the direction of the magnetic pull, and then the data is read by detecting the changes in direction on the
A data array is defined as “data that have been sorted in ascending or descending order” (Shannon, Groebner, Fry, & Smith, 2002, 72). The following section presents the data presented in Table 1 as a data array.
The data and information I have collected is directly from the team of Australian Hardware team so this information is valid enough to be used for research of the given
But In this proposed model, we logically group the roles instead of hosts and storage devices. Roles are assigned to hosts. There are many-to-many relationship between roles and hosts. Multiple hosts may have a single role and multiple roles may be assigned to a single host. The relationship between roles and the storage is also many-to-many. The specific access rights are associated with each role to access the storage.
Zollinger, H. (2001). AS/RS Application, benefits and Justification in Comparison to Other Storage Methods. http://www.mhia.org/PSC/pdf/asrswhitepaper2.pdf. Retrieved May, 2007.
Palmer, Lorrie. “Rebooting the Mythical Array.” Extrapolation. 53.1. (2012): 122. InfoTrac Academic One. Web. 27. Nov. 2013.
In 1977, Larry Ellison, Bob Miner, and Ed Oates founded System Development Laboratories. After being inspired by a research paper written in 1970 by an IBM researcher titled “A Relational Model of Data for Large Shared Data Banks” they decided to build a new type of database called a relational database system. The original project on the relational database system was for the government (Central Intelligence Agency) and was dubbed ‘Oracle.’ They thought this would be appropriate because the meaning of Oracle is source of wisdom.
Hipschma, Ron. " The Problem -- Mountains of Data." How SETI @Home Works (1999). 29 January 2000 http://www.nitehawk.com/rasmit/.
This motherboard has Universal Serial Bus (USB) 2.0. This gives the advantage of high-speed transfer between external sources such as video cameras, digital cameras, scanners, audio recorders, and any other possible external components. USB 2.0 is faster than fire wire, which is currently the most widely used transfer hardware.
File servers are an important part of any business. The file server is the central location of files for a business small or big. The file server can be a cloud accessible server which grants accesses anywhere. The file server can also be a dedicated server which is only used on the business network. I am going to touch on the specifications of a file server. This means I am going to go over CPU, memory, bus, DMA, storage, interrupts, input/output peripherals, and monitors of a files server.
The network services and application recovery times are additive in case of a disaster that affects servers and the LAN. However, a WAN disaster takes significantly longer to recover from due to the installation schedules of telecommunications providers. During this delay, server and LAN recovery could be completed so the WAN recovery time would be the only time applicable to the RTO (Information Technology Disaster Recovery Plan, 2012).
Fault tolerant techniques are based on time redundancy or space redundancy or combination of both. As mentioned previously, a sensor has a limited computation power, so time redundancy techniques are not supposed to be of beneficial. Traditional techniques in backing up sensors are based on double and triple redundancy, which doesn’t satisfy the requirement of having a reliable network with a minimum number of sensors.
Paging is one of the memory-management schemes by which a computer can store and retrieve data from secondary storage for use in main memory. Paging is used for faster access to data. The paging memory-management scheme works by having the operating system retrieve data from the secondary storage in same-size blocks called pages. Paging writes data to secondary storage from main memory and also reads data from secondary storage to bring into main memory. The main advantage of paging over memory segmentation is that is allows the physical address space of a process to be noncontiguous. Before paging was implemented, systems had to fit whole programs into storage, contiguously, which would cause various storage problems and fragmentation inside the operating system (Belzer, Holzman, & Kent, 1981). Paging is a very important part of virtual memory impl...
of multiple types of end users. The data is stored in one location so that they
Magnetic Disks (Hard Disk) -.. The topic of magnetic disks is one that involves many physics related phenomena. The intricate structure and design of “Magnetic Disks” (or hard disks) in computers include the principles of Fluid Flow, Rotational Motion, Electromagnetism, and more. This paper will focus mainly on the previously listed physics occurrences, and the design that goes into engineering the magnetic disk to include them. These physics principles are utilized in such a way that makes the hard disk a very common and useful tool, in this day and age.