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RAID

RAID
RAID (originally redundant array of inexpensive disks; now commonly redundant array of independent disks) is a data storage virtualization technology that combines multiple disk drive components into a logical unit for the purposes of data redundancy or performance improvement.[1] History[edit] Although not yet using that terminology, each of the five levels of RAID named in the paper were well established in the art prior to the paper's publications, for example: Around 1983, DEC began shipping subsystem mirrored RA8X disk drives (now known as RAID 1) as part of its HSC50 subsystem.[3]Around 1988, the Thinking Machines DataVault used error correction codes (now known as RAID 2) in an array of disk drives.[4] A similar approach was used in the 1970s on the IBM 3330.[5]In 1977, Norman Ken Ouchi at IBM filed a patent disclosing what was subsequently named RAID 4.[6]In 1986, Clark et al. at IBM filed a patent disclosing what was subsequently named RAID 5.[7] Concept[edit] Standard levels[edit]

RAID History[edit] Each of the five levels of RAID named in the paper were well established in the art prior to the paper's publications, for example: Around 1983, DEC began shipping subsystem mirrored RA8X disk drives (now known as RAID 1) as part of its HSC50 subsystem.[7]Around 1988, the Thinking Machines DataVault used error correction codes (now known as RAID 2) in an array of disk drives.[8] A similar approach was used in 1970s on the IBM 3330.[9]In 1977, Norman Ken Ouchi at IBM filed a patent disclosing what was subsequently named RAID 4.[10]In 1986, Clark et al. at IBM filed a patent disclosing what was subsequently named RAID 5.[11] Standard levels[edit] A number of standard schemes have evolved. RAID 0 comprises striping (but no parity or mirroring). RAID 1 comprises mirroring (without parity or striping). RAID 2 comprises bit-level striping with dedicated Hamming-code parity. RAID 3 comprises byte-level striping with dedicated parity. Comparison[edit] Nested (hybrid) RAID[edit]

Welcome to Pando | Thanks for Sharing Hard disk drive A disassembled and labeled 1997 HDD laying atop a mirror. Overview of how an HDD functions The two most common form factors for modern HDDs are 3.5-inch in desktop computers and 2.5-inch in laptops. HDDs are connected to systems by standard interface cables such as SATA (Serial ATA), USB or SAS (Serial attached SCSI) cables. As of 2012[update], the primary competing technology for secondary storage is flash memory in the form of solid-state drives (SSDs). History[edit] Video of modern HDD operation (cover removed) HDDs were introduced in 1956 as data storage for an IBM real-time transaction processing computer[3] and were developed for use with general purpose mainframe and minicomputers. In 1961 IBM introduced the model 1311 disk drive, which was about the size of a washing machine and stored two million characters on a removable disk pack. In 1973, IBM introduced a new type of HDD codenamed "Winchester". External HDDs remained popular for much longer on the Apple Macintosh.

Standard RAID levels The standard RAID levels are a basic set of RAID configurations that employ the techniques of striping, mirroring, or parity to create large reliable data stores from general purpose computer hard disk drives. The most common types today are RAID 0 (striping), RAID 1 and variants (mirroring), RAID 5 (distributed parity) and RAID 6 (dual parity). RAID levels and their associated data formats are standardized by the Storage Networking Industry Association in the Common RAID Disk Drive Format (DDF) standard.[1] RAID 0[edit] Diagram of a RAID 0 setup A RAID 0 (also known as a stripe set or striped volume) splits data evenly across two or more disks (striped) without parity information for speed. A RAID 0 can be created with disks of differing sizes, but the storage space added to the array by each disk is limited to the size of the smallest disk. The diagram shows how the data is distributed into Ax stripes to the disks. Performance[edit] RAID 1[edit] Diagram of a RAID 1 setup RAID 2[edit] . and

SCSI Single Ended Parallel SCSI icon/logo. SCSI is an intelligent, peripheral, buffered, peer to peer interface. It hides the complexity of physical format. History[edit] SCSI was derived from "SASI", the "Shugart Associates System Interface", developed c. 1978 and publicly disclosed in 1981.[2] A SASI controller provided a bridge between a hard disk drive's low-level interface and a host computer, which needed to read blocks of data. Larry Boucher is considered to be the "father" of SASI and SCSI due to his pioneering work first at Shugart Associates and then at Adaptec.[4] Until at least February 1982, ANSI developed the specification as "SASI" and "Shugart Associates System Interface;"[5] however, the committee documenting the standard would not allow it to be named after a company. The "small" part in SCSI is historical; since the mid-1990s, SCSI has been available on even the largest of computer systems. SCSI is popular on high-performance workstations and servers. Interfaces[edit]

Disk array controller A disk array controller name is often improperly shortened to a disk controller. The two should not be confused as they provide very different functionality. Front-end and back-end side[edit] A disk array controller provides front-end interfaces and back-end interfaces. Back-end interface communicates with controlled disks. A single controller may use different protocols for back-end and for front-end communication. Enterprise controllers[edit] Those external disk arrays are usually purchased as an integrated subsystem of RAID controllers, disk drives, power supplies, and management software. Simple controllers[edit] A simple disk array controller may fit inside a computer, either as a PCI expansion card or just built onto a motherboard. As of February 2007[update] Intel started integrating their own Matrix RAID controller in their more upmarket motherboards, giving control over 4 devices and an additional 2 SATA connectors, and totalling 6 SATA connections (3Gbit/s each). History[edit]

Dynamic random access memory Dynamic random-access memory (DRAM) is a type of random-access memory that stores each bit of data in a separate capacitor within an integrated circuit. The capacitor can be either charged or discharged; these two states are taken to represent the two values of a bit, conventionally called 0 and 1. Since even "nonconducting" transistors always leak a small amount, the capacitors will slowly discharge, and the information eventually fades unless the capacitor charge is refreshed periodically. Because of this refresh requirement, it is a dynamic memory as opposed to SRAM and other static memory. The main memory (the "RAM") in personal computers is dynamic RAM (DRAM). The advantage of DRAM is its structural simplicity: only one transistor and a capacitor are required per bit, compared to four or six transistors in SRAM. History[edit] The cryptanalytic machine code-named "Aquarius" used at Bletchley Park during World War II incorporated a hard-wired dynamic memory. Operation principle[edit]

Standard RAID levels In computer storage, the standard RAID levels comprise a basic set of RAID configurations that employ the techniques of striping, mirroring, or parity to create large reliable data stores from multiple general-purpose computer hard disk drives (HDDs). The most common types are RAID 0 (striping), RAID 1 and its variants (mirroring), RAID 5 (distributed parity), and RAID 6 (dual parity). RAID levels and their associated data formats are standardized by the Storage Networking Industry Association (SNIA) in the Common RAID Disk Drive Format (DDF) standard.[1] RAID 0[edit] Diagram of a RAID 0 setup RAID 0 (also known as a stripe set or striped volume) splits data evenly across two or more disks (striped), without parity information and with speed as the intended goal. A RAID 0 setup can be created with disks of differing sizes, but the storage space added to the array by each disk is limited to the size of the smallest disk. Performance[edit] RAID 1[edit] Diagram of a RAID 1 setup RAID 2[edit] .

DDR SDRAM Generic DDR-266 memory in the 184-pin DIMM form Corsair DDR-400 memory with heat spreaders Double data rate synchronous dynamic random-access memory (DDR SDRAM) is a class of memory integrated circuits used in computers. DDR SDRAM, also called DDR1 SDRAM, has been superseded by DDR2 SDRAM and DDR3 SDRAM, neither of which is either forward or backward compatible with DDR1 SDRAM -meaning that DDR2 or DDR3 memory modules will not work in DDR1-equipped motherboards, and vice versa. With data being transferred 64 bits at a time, DDR SDRAM gives a transfer rate of (memory bus clock rate) × 2 (for dual rate) × 64 (number of bits transferred) / 8 (number of bits/byte). Thus, with a bus frequency of 100 MHz, DDR SDRAM gives a maximum transfer rate of 1600 MB/s. "Beginning in 1996 and concluding in June 2000, JEDEC developed the DDR (Double Data Rate) SDRAM specification (JESD79) Specification standards[edit] Comparison of memory modules for desktop PCs (DIMM). Physical DDR layout DRAM density Ranks

ICH10R Raid5 Help - Page 2 - Overclock.net - Overclocking.net Sorry to revive an old thread but i have a continuation to this. I did eventually get the raid set up with 2 arrays instead of 2 partitions like suggested and ended up with a bootable raid 5 50gb for an os and a nonbootable 2.6tb raid 5 array for data, both set with a 64k stripe size. TBH things didnt impove a great deal, ever sinse ive had it loaded transfers have been very slow. 10-15mb cross gigabit network and 20-30mb from raid to esata drive which tbh i think is poor. i did a few things, played with jumbo frames, set all adapters to 4k like was suggested on a post i read which didnt seem to help. eventually i got tired of being able to redownload films faster than i could stabily stream them that i backed up my 2tb of data and flattened my raid completely. Just out of curiosity i loaded freenas to a 4gb usb pen and fired it up. What troubles me is that a purpose designed server os like win2k8 cant seem to achieve this.

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