RAID Technologies Overview

The primary purpose of redundancy in RAID systems is to improve data reliability by storing extra information so data can be recovered if a disk fails.

RAID 0 improves performance through block striping, which allows for non-redundant storage of unique data across multiple disks.

RAID 1 features mirrored disks, where all data is duplicated across two or more disks for high reliability.

<p>RAID 3 uses bit-interleaved parity through an XOR gate for error detection.</p> Signup and view all the answers

<p>RAID 5 distinguishes itself by distributing parity across all disks, whereas RAID 4 maintains a single dedicated parity disk.</p> Signup and view all the answers

<p>RAID 6 is more resilient than RAID 5 because it employs P+Q redundancy, allowing it to withstand the failure of two disks simultaneously.</p> Signup and view all the answers

<p>The primary difference is that software RAID is implemented entirely in software, while hardware RAID uses dedicated hardware for RAID functionalities.</p> Signup and view all the answers

<p>Indexing in a DBMS optimizes data retrieval by organizing and allowing quick access to large datasets.</p> Signup and view all the answers

<p>The primary purpose of indexing is to improve the speed of data retrieval operations on a database table.</p> Signup and view all the answers

<p>A primary index is created on the primary key field, uniquely identifying records, while a secondary index is created on a non-primary key field to facilitate fast access to non-unique records.</p> Signup and view all the answers

<p>A clustered index sorts data rows in a table based on index values, which affects the physical order of the records in storage.</p> Signup and view all the answers

<p>Static hashing refers to a fixed number of buckets for data storage, and its primary limitation is overflow when the number of records exceeds available buckets.</p> Signup and view all the answers

<p>Hashing is not ideal for range queries since it requires an exact key match, making it inefficient for searching ranges of values.</p> Signup and view all the answers

<p>A deadlock occurs when two or more transactions are waiting indefinitely for each other to release locks on resources.</p> Signup and view all the answers

<p>Dynamic hashing allows the number of storage buckets to grow or shrink based on data needs, which helps to reduce overflow problems.</p> Signup and view all the answers

<p>An advantage of indexing is that it speeds up search queries for large datasets; a disadvantage is that it requires additional storage and needs maintenance.</p> Signup and view all the answers

<p>The three conditions are Hold and Wait, No Preemption, and Circular Wait.</p> Signup and view all the answers

<p>In the Wait-Die schema, a transaction waits for a resource only if it has a higher priority than the current transaction; otherwise, it is aborted.</p> Signup and view all the answers

<p>In the Wound-Wait schema, a higher priority transaction can preempt a lower-priority transaction that holds a resource.</p> Signup and view all the answers

<p>A wait-for graph is a directed graph representing transactions as nodes and edges indicating which transactions are waiting for resources held by others.</p> Signup and view all the answers

<p>A B-tree of order m contains at most m-1 keys per node, every internal node has m children, and all leaves are at the same level.</p> Signup and view all the answers

<p>When more keys are added, the B-tree splits the nodes at the midpoint, redistributing keys and maintaining the order.</p> Signup and view all the answers

<p>One advantage of using a B-tree is reduced disk access due to its balanced structure that allows for efficient read and write operations.</p> Signup and view all the answers

<p>Cascading rollback occurs when the rollback of one transaction leads to the rollback of other dependent transactions.</p> Signup and view all the answers