Four types of data storage structures

There are four types of data storage structures: sequential storage, linked storage, index storage, and hash storage. Sequential and linked structures apply to memory structures. Index and hash structures are suitable for interaction between external memory and memory.

Sequential storage: In computer, a group of contiguous storage units are used to store the data elements of a linear table in sequence, called the sequential storage structure of a linear table. Features: Random access table elements; Insertion and deletion operations require moving elements.


Linked storage: In computer, data elements of a linear table are stored in an arbitrary set of storage units (which may be contiguous or discontinuous). It does not require logically adjacent elements to be physically adjacent. Therefore, it does not have the weakness of sequential storage structure, but it also loses the advantage of random access of sequential table.

Features:

  • Lower storage density compared to sequential storage structure (each node is composed of data field and pointer field, so using sequential storage structure can store more data than using linked storage structure in the same storage space.
  • Logically adjacent nodes do not have to be physically adjacent.
  • Flexible insertion and deletion (no need to move the node, only need to change the pointer in the node).
  • Linked storage is slower than sequential storage when finding nodes.
  • Each node is composed of data field and pointer field.


Index storage: In addition to establish storage node information, also establish additional index table to identify the node address. An index table consists of several index entries. The index storage structure uses the index number of the node to identify the node storage address, which has the advantage of fast retrieval, but the disadvantage is that additional index tables occupy more storage space. 


Hash storage: Hash storage is a lookup technology that tries to establish a definitive relationship between the storage location of data elements and keys. The basic idea of hash storage is that the storage address of the node is determined by the key of the node.

Comments

Post a Comment

Popular posts from this blog

Introduction to the basic architecture and operation of Internet Small Computer Systems Interface

Image
 iSCSI is an acronym for Internet Small Computer Systems Interface, an Internet Protocol (IP)-based storage networking standard for linking data storage facilities. iSCSI works on top of the Transport Control Protocol (TCP), and provides block-level access between the iSCSI initiator and the storage target by carrying SCSI commands over a TCP/IP network. iSCSI is used to facilitate data transfers over intranets and to manage storage over long distances. iSCSI can be used to transmit data over local area networks (LANs), wide area networks (WANs), or the Internet, and can  enable  location-independent data storage and retrieval. Overview of the overall architecture iSCSI   is a remote mapping technology that maps a storage device on a remote server to the local area and presents it as a block device (which can be thought of as a disk). From the perspective of the normal user, the mapped disk is no different from the locally connected disk. This mapping is based on the SCSI protocol, whi
Read more

What is MPIO and how to use it?

M PIO is an acronym for MultiPath Input Output. This is a framework designed to configure load balancing and failover processes by providing multiple logical paths between storage devices and the server. The logical paths can be created through redundant physical components like buses, controllers, switches or bridge devices. Should one or more controllers, ports or switches fail, the server can route the I/O through an alternate path, the remaining controller, port or switch transparently and with no changes visible to the applications, other than perhaps resulting in increased latency.   Microsoft provides Device Specific Module (DSM) in Server 2008, 2012 and 2016, supports Asymmetric Logical Unit Access (ALUA), and can configure Multipath I/O (MPIO) environment with the storage device conforming to the SCSI Primary Commands (SPC) specification. DSM provides the load balancing policies, and load balance policies are generally dependent on the ALUA of the storage array attached to Win
Read more

Why is QStora a software-defined storage controller

Storage controller  is a device that manages the physical  disk drives  and presents them to the computer as  logical units .  It is also called "storage processor" or "array controller". Storage controller integrates the storage space in multiple storage devices and provides them as a single storage space to the client. When receiving a write data request from the client, the storage controller decides which of the multiple storage devices to allocate the data to, and stores the data in the selected one. When receiving a read request from the client, the storage controller finds the location where the data is stored, reads the data from the storage device and transmits it to the client. The storage controller performs these tasks in an efficient and stable manner. In addition to reading and writing data, the storage controller also implements various value-added functions, including dynamic allocation of volume capacity, snapshots, and so on. QStora is a software-d
Read more