block level

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block level

Reading and writing a disk at the physical level. The disk controller in every computer and server reads and writes the disks at the block level. In storage area networks (SANs), where the disks are in cabinets external to the server, read/write access is also at the block level.

Block Level Vs. File Level
An application accesses data by file name (logical), which is translated into block level (physical) for reading and writing by the operating system's file system.

Users always deal with data at the file level; however, database and network administrators may get involved at the block level, because they can stipulate where data are physically stored for performance issues.

NAS vs. SAN
Although a stand-alone unit with its own disks, a network attached storage (NAS) device has its own file system for file level access. Because a SAN uses block level access and has no file system with its associated overhead, a SAN is much faster than a NAS. See SAN, NAS and file system.

Remote Block Level Access
With IP storage, block level access can be extended via the IP protocol to remote locations. See SAN and IP storage.

Blocks Are Also Logical
Modern drives maintain their own tables of good and bad sectors and remap requests on the fly. As a result, the physical block reads and writes are translated by the drive into actual sector reads and writes, making the block access somewhat like a logical request, rather than 100% physical.


References in periodicals archive ?
In an online notice, the military also said: "We urge soldiers to refrain from visiting digital token exchanges to avoid disappointment from our decision to block access to relevant sites.
It cited a law that allows it to block access to individual web pages or entire websites for the protection of public order, national security or the well being of the public.
com/article/us-russia-linkedin-diplomacy-idUSKBN13D0ST) a statement to Reuters: "The United States is deeply concerned by Russia's decision to block access to the website LinkedIn.
ySTANBUL (CyHAN)- Although the ystanbul 7th Penal Court of Peace has asked Twitter to block access to the account of Twitter whistleblower Fuat Avni, who recently claimed that President Recep Tayyip Erdoy-an's son Bilal Erdoy-an went to Italy with a large amount of money on Sept.
INDIA has ordered internet service providers (ISPs) to block access to more than 850 adult websites in what the government has described as a way to protect social decency.
Internet providers reported that they received a letter with requirement to block access to nearly three hundred different websites, including the social network Facebook, Wikipedia, Russian news websites, and others.
Summary: Internet providers are set to block access to six pornographywebsites based on a decision issued Monday by the Telecommunications Ministry.
A complete ban on social media platforms cannot be approved," he said, adding that it is not "technically possible to totally block access to platforms used all over the world.
The government said it would require Internet service providers (ISPs) to install filters to block access to child pornography.
But the investigation, by the ECHO's sister paper the Daily Mirror, tested 129 free Wi-Fi hotspots around the country and found that 32 of them - one in four - did not block access to a free website that streams hardcore pornographic videos.
This council block access loan websites It comes on the back of Newcastle City Council having already agreed to block access to websites boasting quick loans with high interest at its libraries and customer service points.
19 ( ANI ): Egypt's telecoms ministry has refused to block access to YouTube and has filed an appeal to reverse a court order asking it to do so.