Storage Provisioning and Networking - Deploying and Managing a Cloud Infrastructure - page 248

Means (tools) by which the data was created

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Data/Blob

The word data is the plural of datum , a past participle form of the Latin word dare , which
means “to give.” In computer science, data refers to pieces of information, such as anything
that is based on numbers, words, images, audio, and video.
A binary large object (blob) is basically an amorphous collection of binary data stored
as a single unit in a file system or, more commonly, in a database management system
(DBMS). Blobs are generally used to store nontextual data including images, audio, and
video. Blobs may also be used to store executable code.

Extended Metadata

Extended or additional metadata is the metadata that is derived from application-specific
or user-specific information about the access and usage of data. The purpose is to build
sophisticated and personalized indexing schemes.
Furthermore, additional metadata is used to support data management policies, such as
a policy to migrate data objects from one storage tier to another. This is especially relevant
for load balancing during peak performance hours.

Replicas

A replica represents an exact mirror image reproduction of an original item. In computer
science, a soft-copy replica might be indistinguishable from its original due to the lack of
hard effects created during the hard-copy process and the surrounding environment.
A soft-copy replica of an item creates a symbolic link (also called symlink or soft link) to
another file or directory. It is just an additional reference to an already existing file. Hard-
copying an item creates an identical copy of the item in storage media. The newly created
item can be considered a clone. The two items—the actual and the copy—are indistinguish-
able, and each has an individual presence on the storage media. This is opposed to soft-
copying, where an item may have two or more references.

Policies and Access Control

Policies in computer systems are used to define networking rules, data storage, data security,
data archiving, data deletion, access control, and a multitude of other activities related to
computer systems.
Access control policy defines selective restriction of physical or virtual access to one or
more computer resources in order to establish physical and information security. The act