Computer Storage Devices

A storage device is used in the computers to store the data. Storing data one of the main features of the modern computers. Any sort of computational hardware that is utilized for storing, porting, or extracting data files and objects is referred to as a storage device. Information can be held and stored in storage devices both momentarily and permanently. They can be found both within and outside of a computer, server, or computing device.

A storage device is used to save, transport, and retrieve data. It has the ability to store and retain information for a short or extended period of time. Except for hardware firmware, it virtually completely stores all data and applications on a computer. It is available in a variety of shapes and sizes, based on the needs and functions. (Techopedia, 2020)

There are four main types of storages
(01). Primary Storage
(02). Secondary Storage
(03). Tertiary Storage
(04). Off-line Storage

(01). Primary Storage
Also known as main memory. It is directly or indirectly connected to the central processing unit via a memory bus. Primary storage is the part of the computer that stores actively used data, programs, and instructions. Primary storage is located on the motherboard. As a result, data can be read from and written to primary storage extremely quickly. This gives the processor fast access to the data and instructions that the primary storage holds. (Bitesize, 2021). There are four types of primary storage
(01). ROM (Read Only Memory)
(02). RAM (Random Access Memory)
(03). Flash Memory
(04). Cache Memory
RAM, which is volatile, and ROM, which is non-volatile, are the two basic types of primary storage. Even after the computer is turned off, non-volatile memory retains its contents. When power is gone, volatile memory loses its contents.

ROM — Non-volatile primary storage is referred to as ROM. When the computer is turned off, it saves its contents. This memory is used as the computer begins to boot up. Small programs called firmware are often stored in ROM chips on hardware devices (like a BIOS chip) and they contain instructions the computer can use in performing some of the most basic operations required to operate hardware devices. ROM memory cannot be easily or quickly overwritten or modified. The ROM is perfect for storing the instructions and data that the computer requires to function. These instructions and data are often pre-programmed by the computer’s manufacturer and cannot be changed. The BIOS (Basic Input Output System) is an example of a program that is stored in ROM. The BIOS runs as soon as the computer is switched on. It checks that the hardware is functioning correctly then loads the computer’s operating system. Because the BIOS is always needed it is stored in ROM. (Flynn, 2003)

RAM — It is called random access memory because any of the data in RAM can be accessed just as fast as any of the other data. RAM is a type of memory that is used to store data and instructions that are actively in use. RAM is utilized to store the operating system as well as any open documents and programs on a modern PC. There are two types of RAM
DRAM (Dynamic Random Access Memory)
SRAM (Static Random Access Memory)

Cache — Cache memory is a type of high-speed volatile random access memory (RAM) which is built into the processor. Data can be transferred to and from cache memory more quickly than from RAM. As a result, cache memory is used to temporarily hold data and instructions that the processor is likely to reuse. This allows for faster processing as the processor does not have to wait for the data and instructions to be fetched from RAM. (Bitesize, 2021). Most computers today come with L3 cache and L2 cache, while older computers included only L1 cache.

(02). Secondary Storage
Any non-volatile storage device, whether internal or external to the computer, is referred to as a secondary storage device. It can be any storage device that allows for long-term data storage in addition to main storage. (Techopedia, Secondary Storage Device, 2020) It is not directly accessible by the CPU. There are three main types of secondary storage in a computer system.
(01). Solid state storage devices, such as USB memory sticks
(02). Optical storage devices, such as CD, DVD and Blu-ray discs
(03). Magnetic storage devices, such as hard disk drives
Computer usually uses its input/output channels to access secondary storage and transfers the desired data using intermediate area in primary storage.

Hard Disk — The hard disk drive is the main, and usually largest data storage device in a computer. Hard disk speed is the speed at which content can be read and written on a hard disk. A hard disk unit comes with a set rotation speed varying from 4500 to 7200 rpm. Disk access time is measured in milliseconds. A magnetic disk’s medium contains iron particles, which can be polarized-given a magnetic charge-in one of the two directions. A disk drive uses read/write heads containing electromagnets to create magnetic charges on the medium. Before a magnetic disk can be used, it must be formatted-a process that maps the disk’s surface and determines how data will be stored. During formatting the drive creates circular tracks around the disk’s surface, then divides each track into sectors. The OS organizes sectors into groups, called clusters, then tracks each file’s location according to the clusters it occupies.

(03). Tertiary Storage
Typically it involves a robotic mechanism which will mount (insert) and dismount removable mass storage media into a storage device. It is a comprehensive computer storage system that is usually very slow, so it is usually used to archive data that is not accessed frequently. This is primarily useful for extraordinarily large data stores, accessed without human operators.
Magnetic Tape — A magnetically coated strip of plastic on which data can be encoded. Tapes for computers are similar to tapes used to store music. Tape is much less expensive than other storage mediums but commonly a much slower solution that is commonly used for back up.
Optical Disc — Optical disc is any storage media that holds content in digital format and is read using a laser assembly is considered optical media. The most common types of optical media are
(01). Blu-ray Disc (BD)
(02). Compact Disc (CD)
(03). Digital Versatile Disc (DVD)

(04). Off-line Storage
Also known as disconnected storage. Off-line storage is a computer storage on a medium or a device that is not under the control of a processing unit. It must be inserted or connected by a human operator before a computer can access it again.

Floppy Disk — A soft magnetic disk. Floppy disks are portable. Floppy disks are slower to access than hard disks and have less storage capacity, but they are much less expensive. Can store up to 1.44MB. Two common sizes 5 ¼” and 3 ½”.

Zip Diskette — Hardware data storage device developed by Iomega that functions like a standard 1.44” floppy drive. Capable to hold up to 100MB of data or 250MB of data on new drives. Now it less popular as users needed larger storage capabilities.

USB Flash Drive — A small, portable flash memory card that plugs into a computer’s USB port and functions as a portable hard drive. Flash drives are available in sizes such as 2GB, 4GB, and up to 256GB and are an easy way to transfer and store data. This type of storage media is called solid state memory, and differs from optical and magnetic drives.

Memory Card — An electronic flash memory storage disk commonly used in consumer electronic devices such as digital cameras, MP3 players, mobile phones, and other small portable devices. Memory cards are usually read by connecting the device containing the card to your computer, or by using a USB card reader.

Online Cloud Storage

Data is transported and kept on distant storage systems, where it is maintained, managed, backed up, and made available to users across a network. Users often pay a monthly fee based on how much data they save in the cloud.

The foundation of cloud storage is a virtualized storage system with accessible interfaces, near-instant elasticity and scalability, multi-tenancy, and metered resources. Cloud-based data is kept in logical pools on various commodity storage servers on premises or in a third-party cloud provider’s data center.

There are three main types of cloud storages, based on different access models. (Chai, 2021)
(01). Public
(02). Private
(03). Hybrid

Public cloud — On a subscription basis, these storage services provide a multi-tenant storage environment that is best suited for unstructured data. Data is stored in the data centers of the service provider, which are spread across various countries or continents. Customers typically pay on a per-use basis, similar to how they pay for utilities. In many circumstances, transaction fees are assessed based on the frequency and volume of data accessed. The following services are the most popular in this market.
(01). Google Drive
(02). Microsoft One Drive
(03). Amazon Glazier
(04). Dropbox
Private cloud — A private cloud storage service is an in-house storage resource that is set up as a separate environment that is protected by a firewall. Internally hosted private cloud storage methods mimic some of the features of commercial public cloud services, such as easy storage resource allocation and access for corporate users, as well as object storage protocols. Users who demand additional flexibility and control over their data, as well as those who have severe data security or regulatory requirements, should use private clouds.
Hybrid cloud — This cloud storage solution combines private cloud storage with third-party public cloud storage services, as well as a layer of orchestration management to operationally link the two platforms. (Chai, 2021)

Most used storage devices

Optical discs and flash memory devices are most popular, and to much lesser extent removable hard disk drives. In enterprise uses, magnetic tape is predominant. Older examples are floppy disks, Zip disks, or punched cards.

Your computer’s physical capacity is no longer a factor in storage capacity. There are numerous choices for storing your files while preserving space on your computer, phone, or tablet. You can unload files onto a physical storage device if your devices are slow and running out of capacity. Better still, store your information to the cloud using the latest storage technology.

Cloud storage has much larger storage capacity than USB flash drives and other physical storage choices. You won’t have to search through each device to find the right file this way.

Characteristics of computer storage devices

References

BBC. (2021). Hardware and network technologies — CCEA. Retrieved from BBC: https://www.bbc.co.uk/

Bitesize. (2021, January 20). Memory. Retrieved from BBC: https://www.bbc.co.uk

Chai, W. (2021, June 1). Cloud Storage. Retrieved from TechTarget: https://www.techtarget.com/

Flynn, M. J. (2003, January 3). Read-only memory (ROM). Retrieved from Research Gate: https://www.researchgate.net

Techopedia. (2020, August 11). Secondary Storage Device. Retrieved from Techopedia: https://www.techopedia.com

Techopedia. (2020, August 17). Storage Device. Retrieved from Techopedia: https://www.techopedia.com

J.V.Lakshan