What’s a storage medium (storage media)?
In computer systems, a storage medium is a bodily system that receives and retains digital information for purposes and customers and makes the info obtainable for retrieval. The storage medium is perhaps inside a pc or different system or connected to a system externally, both straight or over a community. The plural type of this time period is storage media.
Early types of storage media included laptop paper tape with holes punched into it. Every gap corresponded to a single bit of information. A paper tape reader would interpret the outlet and convert it to a quantity. Punched playing cards had been additionally extensively used within the early days of information storage and at one time saved a lot of the world’s digital info.
Paper tape and punched playing cards had been supplanted by magnetic tape, which ultimately gave approach to magnetic floppy disks. Laborious disk drives (HDDs) and solid-state drives (SSDs) at the moment are the first types of storage.
How storage media works
Media utilized in laptop storage obtain messages within the type of information, through software program instructions from a bunch system. The kind of media wanted to carry the info will depend on the info’s enterprise worth, relevant compliance laws, efficiency and availability necessities and different components.
A storage medium could also be inside to a computing system, corresponding to a pc’s SSD, or a detachable system corresponding to an exterior HDD or common serial bus (USB) flash drive. There are additionally different forms of storage media, together with magnetic tape, compact discs (CDs) and non-volatile reminiscence (NVM) playing cards.
A corporation’s storage is usually categorised as major and secondary. Initially, major storage referred to information that’s stored in reminiscence for quick retrieval by a pc’s processor, and secondary storage referred to information saved on non-volatile gadgets corresponding to SSDs and HDDs.
Extra just lately, major storage has come to discuss with any sort of reminiscence that helps a company’s day-to-day workloads. For instance, the HDDs, SSDs or storage-class reminiscence (SCM) gadgets that retailer information for mission-critical purposes are thought of major storage. In distinction, secondary storage can discuss with absolutely anything else, together with optical discs or tape techniques that help long-term information retention.
In tiered storage, automated software program insurance policies are used to maneuver information between totally different storage varieties, corresponding to HDDs, SSDs and cloud platforms.
The time period storage medium can discuss with a storage system in its entirety or to a person element that is used together with or is a part of one other system. As an illustration, the interior HDDs and SSDs in computer systems are generally known as storage media, as are CDs, however the CD drive itself is considered a storage system or system, fairly than storage medium.
Equally, an array is a whole storage system made up of particular person storage media. An array is usually decoupled from the Software Server and connected to a separate server and accessed over a community. An array is perhaps made up of HDDs or SSDs, or it is perhaps arrange in a hybrid configuration that blends HDDs and SSDs into an built-in system, with HDDs offering a capability tier that helps the quicker SSDs.
Storage media will be organized in a number of methods, relying on workload necessities. Some well-known configurations embody:
- redundant array of impartial disks (RAID);
- network-attached storage (NAS); and
- storage space community (SAN).
These configurations will not be mutually unique. For instance, a SAN usually arranges storage into RAID configurations.
Various kinds of storage media
Storage media is available in many various kinds, amongst them:
Laborious disk drives
An HDD gives a high-capacity different to magnetic storage media corresponding to tape or floppy disks. It incorporates steel platters coated with a magnetic layer. The platters normally spin repeatedly when a pc is on, storing information in numerous sectors on the magnetic disk.
Laborious disks proceed to be the dominant media for backup storage home equipment, energetic archives and long-term retention. A disk-based backup equipment may additionally embody interfaces to copy information copies, corresponding to clones and snapshots, to tertiary gadgets or a hybrid cloud.
A draw back to HDDs is the reliance on transferring inside mechanisms corresponding to actuators, motors and spindles that may fail and corrupt the drive. Nonetheless, HDDs stay widespread in enterprise disk arrays because of their rising capacities and the power to rewrite information on the disk. In 2017, Western Digital Corp. launched a 14 TB HDD, making it the most important in the marketplace at the moment. Seagate Know-how adopted in 2019 with a 16 TB HDD. Western Digital has since countered with a 20 TB HDD.
Some HDDs use shingled magnetic recording (SMR) as an alternative choice to standard magnetic recording. An SMR methodology permits for better areal density by permitting information to be written in partially overlapping tracks on the disk. SMR drives work optimally with information that’s repeatedly written, corresponding to disk-based archiving and backup, however it may negatively influence efficiency for different forms of workloads.
Seagate, Western Digital and Toshiba are among the many main producers of SMR-based disks. In 2020, nevertheless, controversy surrounded the three distributors for allegedly promoting HDDs with out disclosing they used SMR expertise.
RAID works by putting information on a number of disks and balancing enter/output (I/O) operations throughout these disks. RAID can enhance efficiency, fault tolerance or each, relying on the RAID configuration. If RAID is ready up for fault tolerance, the info is protected within the occasion a drive fails. The usage of a number of disks additionally will increase the imply time between failures (MTBF).
Flash reminiscence doesn’t depend upon transferring mechanical elements. As an alternative, information is written to microchips, making storage operations a lot quicker than conventional disks. Nonetheless, information should be erased and rewritten in whole blocks, which might have an effect on a tool’s total endurance.
There are two predominant forms of flash SSDs: NAND and NOR. The names are outlined by their respective logic gates, which decide the basic structure underlying digital circuits.
NAND flash reminiscence is written and browse in blocks, whereas NOR flash reminiscence reads and writes bytes independently. Each forms of flash are utilized in a variety of gadgets. NOR flash tends for use in embedded techniques that help gadgets corresponding to medical gear and scientific devices, in addition to shopper gadgets corresponding to tablets and smartphones. In some instances, NOR serves as a alternative for random entry reminiscence (RAM) or read-only reminiscence (ROM) drives.
NAND flash is used for all sorts of normal storage as a result of it’s far more environment friendly at writes, erases and sequential reads. NAND flash can also be identified for greater density and endurance than NOR, making it appropriate for enterprise storage. Some gadgets use each forms of flash. For instance, a smartphone may depend on NOR besides up the working system (OS) and NAND flash for all different storage.
SSDs primarily based on NAND flash are sometimes categorized by the variety of bits supported by every flash cell. Single-level cell (SLC) NAND shops 1 bit of information per flash cell, which is in both a programmed (0) state or erased (1) state. Multi-level cell (MLC) NAND shops two bits of information per flash cell, triple-level cell (TLC) shops three information bits per cell, and quad-level cell (QLC) shops 4 bits. Producers are at present engaged on penta-level cell (PLC) flash, which squeezes 5 bits into every cell.
Flash storage reminiscence gadgets are divided between shopper gadgets and enterprise storage, with some overlap. Enhancements are constructed into enterprise NAND flash gadgets to help extra write cycles than consumer-grade storage. Smartphones, tablets and different shopper gadgets use reminiscence playing cards that modify in capability and value.
Organizations now use flash-based SSDs extensively for each network-based storage — corresponding to NAS and SAN — and direct-attached storage (DAS), which will be connected externally to a pc or embedded straight throughout the system. Direct-attached SSDs are typically used in its place or adjunct to networked storage arrays.
Inner SSDs are available in quite a few kind components, together with:
- add-in playing cards that make the most of a Peripheral Element Interconnect Categorical (PCIe) serial port;
- disk-on-module (DOM) flash boot drives that mount to a pc’s motherboard;
- flash-based twin inline reminiscence modules (DIMMs) that sit in dynamic random-access reminiscence (DRAM) slots on the motherboard to offer a efficiency cache;
- miniSATA (mSATA) drives and their eventual alternative, 2 SSDs, that are utilized in skinny laptops; and
- storage-class reminiscence, which mixes DRAM and NAND to offer non-volatile reminiscence that runs within the server’s reminiscence area (3D XPoint expertise — developed by Intel and Micron — is an instance of storage-class reminiscence).
SSDs initially had been designed to make the most of present Serial-Connected SCSI (SAS) and Serial-Superior Know-how Attachment (SATA) protocols, however many SSDs now use the non-volatile reminiscence categorical (NVMe) protocol as a result of it may take higher benefit of SSD capabilities.
NVMe makes use of a pc’s PCIe ports to allow an software to speak straight with an information storage system. PCIe-based NVMe SSDs intention to scale back latency and increase throughput. The success of NVMe led to the event of non-volatile reminiscence categorical over materials (NVMe-oF). NVMe-oF makes it doable to make use of NVMe instructions to switch information between a bunch and flash storage system throughout an Ethernet, Fibre Channel or InfiniBand connection.
USB flash drives
A USB flash drive is a kind of detachable storage medium that attaches to a server or different system by means of a USB port. A USB flash drive seldom connects repeatedly to a tool, which might make it much less prone to Trojan horses, viruses or worms.
The time period USB flash drive refers back to the system in its entirety, together with the USB connector, whereas the storage medium is the interior flash chip. USB flash drives can differ in measurement, however they’re usually in regards to the measurement of a thumb, with a design much like SSDs however on a smaller scale. USB flash drives connect to gadgets by sliding into suitable USB ports, making it doable to rapidly switch or copy information. The drives are variously known as reminiscence sticks, keychain drives, thumb drives and leap drives.
Though USB drives are extensively utilized by customers because of their comfort, that ease of use can current a safety danger for enterprises. For safety causes, many firms forbid staff from utilizing private USB drives at work, except particularly approved to take action.
Different detachable flash storage media embody the Safe Digital card (SD card), microSD card, Safe Digital Excessive Capability card (SDHC card), CompactFlash card, SmartMedia card, Sony Reminiscence Stick, MultiMediaCard (MMC) and the xD-Image Card, all of that are discovered primarily in shopper electronics.
Optical disc expertise makes use of lasers to put in writing and browse information. Many optical discs help write as soon as, learn many (WORM) operations solely. When first launched, optical discs may retailer extra information than magnetic HDDs, however that has since modified, and optical discs at the moment are used primarily for prerecorded audio and video recordings or for backup and archival functions. Forms of optical storage media embody Blu-ray discs, DVDs, CDs and CD-ROMs (for read-only information).
Tape was a dominant backup storage medium till the Nineties however was steadily pushed apart by magnetic disk. Even so, tape techniques are nonetheless usually used for high-capacity information archiving and have continued to enhance in density and endurance, largely because of advances within the Linear Tape-Open (LTO) format. LTO-9 pushes the per-tape capability to 45 TB of compressed information and 18 TB of native (uncompressed) information.
Tape libraries are composed of tons of and tons of of bodily tapes. The system that helps a tape library permits customers so as to add or take away tapes, observe a tape’s location and set mount factors for accessing the info on tape.
Some organizations are turning to digital tape library techniques for backup. In such a system, an array of bodily disks is offered as tape to the backup software program. Information is written sequentially as it’s with tape, however learn and write operations are quicker as a result of the info is retrieved from magnetic disks.