Computer Storage devices

What is a Storage Device?

The storage devices are one of the prominent components of a computing device. A storage device is any type of computing hardware that is used for storing, porting or extracting data files and objects (Storage Device, 2020). The storage devices are capable of holding or storing information permanently or temporarily.

What is the usage of a storage device?

The main purpose of a storage device is to store data and information. These data and information may either be the files or documents created by the user or the instructions which are used in executing basic operations of a computer. Through portable storage devices, the user can store and retrieve data from multiple devices. With the advancement of technology, the user can store data in virtual storage services; in online cloud storage softwares. Therefore, the user can store and retrieve information at any time from any computing device.

Types of storage

The primary storage and the secondary storage are the main categories, in terms of the types of storage. The best manner to discuss about these two types is to compare and contrast the two categories.

Examples of primary storage

Random Access Memory (RAM)

This is also known as the main memory of a computer. The main memory is the largest memory area that the CPU can access directly.

There are two types of RAM:

Dynamic Random Access Memory (DRAM)

Static Random Access Memory (SRAM)

A comparison between SRAM and DRAM

Read Only Memory (ROM)

ROM is non- volatile memory, which retains its contents even when the computer is turned off. ROM stores essential programs such as the program that reboots the computer. The computer firmware is stored in ROM chips on hardware devices (the BIOS chip). They contain instructions the computer needs in performing its basic operations.

Types of ROM

Programmable ROM (PROM) — it is a memory chip on which data can be written only once. Once a program has been written to a PROM, it remains forever.Erasable Programmable ROM (EPROM) — EPROM retains its contents until it is exposed to ultraviolet light. The ultraviolet light clears its contents, making it possible to reprogram the memory.

Electronically Erasable Programmable ROM (EEPROM) — it contents can be erased exposing it to an electrical charge.

Cache memory

The cache memory is used to store program instructions that are frequently accessed by software during operation.

Types of cache memories

Level 1 (L1) cache — it is extremely fast but relatively small, and is usually embedded in the processor chip (CPU).

Level 2 (L2) cache — it can be accessed more rapidly than the RAM but less rapidly than the level one cache. It may be located internally or externally to the processor.

Level 3 (L3) cache — this is located in the mother board.

Territory storage

Territory storage can be viewed as a special NAS that uses separate robotic mechanisms to transfer media to a storage drive without the intervention of human beings. (Teritory Storage, n.d.) Since territory storage is a comprehensive storage system that is very slow, it is generally used to archive data that is not accessed regularly.

Territory storage sometimes acts as a scanner performing periodic scans of stored media to detect signs of decay in content and to active recovery mechanisms.(ibid) Examples for high- capacity territory storage systems are the optical jukebox and a tape library as shown below(ibid).

Moreover, commonly used territory storage devices are the magnetic tapes and optical disks which would be discussed in detail under the types of computer storage devices.

Off-line storage

In comparison to territory storage, off-line storage devices should be connected or inserted by a human operator before the computer can access it.It is also known as disconnected storage because its data cannot be accessed by a computer once the device is removed. Thus, it is not a storage device that is under the control of the Central processing Unit (CPU). The off-line storage generally has low capacity and used to transport information physically. (Off line Storage, 2017) One of the advantages of Off-line storage is that it is used to backup processes in the situations like virus attacks, hardware failures or power interruptions.(ibid)

Examples of off-line storage devices are,

· Floppy disk

· Zip diskette

· USB flash drive

· Memory card

which would be discussed under the types of computer storage devices.

Types of Computer storage devices.

Magnetic technology

Magnetic Hard Disk

The hard disk is used as the key secondary memory of a computer. The performance of the hard disk has a great impact on the overall speed of the computer.

A magnetic disk’s medium is consisted of iron particles, which can be polarized in one of two directions. A disk drive uses read/write heads to create magnetic charges on the medium.

There are several types of hard disks. Some of them are,

Small Computer System Interface (SCSI)

Advanced Technology Attachment (ATA)

Serial Advanced Technology Attachment (SATA) –This is a modification of ATA.

Floppy Disk

Floppy disks are slower to access than hard disks and have a less storage capacity. However, they are less expensive than hard disks. The maximum storage capacity of a floppy disk is 1.44 Megabytes (MB). This is a soft and portable magnetic disk. The floppy disk should be inserted to a Floppy Disk Drive (FDD) in order t orea/write data. 5 ¼ and 3 ½ are two common sizes of floppy disks.

Zip diskette

This is a hardware storage device developed by Iomega that functions equally to a Standard 1.44” floppy drive. It is capable of holding of 100 MB of data or 250 MB of data in a new drive. Zip diskette is no longer popular due to its small storage capacity.

Optical storage technology

Optical storage is a term used to signify the storage of data on an optical readable medium.

Compact Disk (CD)

Data is recorded by making traces on a disk, which can be read back with the help of light. Focusing a tiny beam of laser light on a spinning disk is a common modern technique used by computers. Initially, the compact discs that were introduced were CD-ROMs (read-only), but these were followed by CD-Rs (writable compact discs) and CD-RWs (rewritable compact discs) (Goodman, 2021)

Optical drive operation (reading/writing operation)

As displayed in the above image, a laser beam is hit onto the surface of the disk. The light is reflected by the lands/bumps and the light is scattered by the pits. Finally, the reflected laser light is picked up by the light sensitive diode and the light is converted to digital data.

Digital Versatile Disk (DVD)

Though the DVD is the same size as a CD, it has a larger storage capacity. Some DVDs are formatted specificslly for video playbacks while others may contain different types of softwares. (Christensson, 2014)A standard video DVD can store 4.7 GB of data, which is enough to hold over 2 hours of video in 720p resolution.(ibid)

Blu-ray disk

The term “Blu-ray” is derived from the blue violet laser, which is used to read and write data in this type of a disk. More data can be stored on a Blu-ray disk (405 nm) than on the DVD format (650 nm), due to its shorter wavelength. A single layer Blu-ray can store 25 gigabytes (GB), while a dual layer Blu-ray can store 50 gigabytes (GB).

Flash technology / semi-conductor technology

USB flash drives

The USB flash drive is a flash-memory data-storage device that incorporates an integrated USB interface (Goodman, 2021). It is also known as a pen drive, a memory stick or a flash drive.

Flash drives are faster than an optical storage device, due to its lack of moving parts.(ibid) Thus, flash drives are capable of processing higher storage capacity.(ibid)

Secure Digital Cards (SD Cards)

This is a chip, which carries the shape of a rectangular, and it is “chipped off” to prevent the card from being inserted into a device in the wrong way (Goodman, 2021).SD cards are used in many modern electronic devices such as mobile phones and digital cameras.(ibid)

Solid State Drives (SSD)

The Solid State drive is also a flash storage device, which sometimes replicates the traditional hard disk drive. (Goodman, 2021)In comparison to a hard disk drive, the solid-state drive has many advantages including faster read/write speed, noiseless operation, greater reliability, and lower power consumption.(ibid) Yet, the cost is the biggest disadvantage of Solid State Drives.

Online cloud storage devices

The term cloud means a remote location in the field of storage. The online cloud is a cloud storage mechanism the user can store data, at the data center of the cloud service provider, instead of storing in his/her own device. (Singh, 2020) Since data is saved in a cloud, the user can access it at any time from any device.

Cloud storage works on a client-server model, in which a client sends the request to the subscribed cloud service storage and the server at the data center responds to the request. (ibid)Most importantly, cloud storage devices are not physical devices but it is a service.(ibid) There are many service providers of online cloud storage

1. Dropbox

Dropbox is a cloud storage and a synchronization service, developed by the American company “Dropbox”. (Singh, 2020)

Features of Dropbox (ibid)

• It does not have a data limit and the user can share any type of file in this platform.
• Dropbox supports multiple operating systems such as Windows, Mac OS, Linux, Android and iOS.
• Yet, since drobox does not provide free storage space, it is expensive for the single users.

2. Google Drive (ibid)

As the name suggests, it is developed by the Google Company, which is introduced as a built-in integration for the devices that use the android operating system

Features of Google Drive (Singh, 2020)

• This is the only online storage service that provides 15GB of free space to its every user.
• The user can also connect with several third-party applications with Google Drive.
• Google Drive does not focus on the data security, the security measures (such as a password) is not assigned to a shared file.
• There is a limitation of the storage space, which is five terabytes (5 TB).

3. iCloud (ibid)

• This is the online storage service provided by the Apple incorporation. Thus, it is available online on Apple devices.
• Especially, iCloud also stores data of other Apple apps such as mail, calendar, contact, Reminder, Safari, etc.
• An Android App for iCloud is not available.

Most used storage devices

The storage devices which were popular at past are sometimes not used today. So, at present we come across with certain storage devices more often than other devices. The zip diskettes are no longer in use due to small storage capacity. The hard drives have started to be replaced by Solid State Drives due to their reliability and speed. Similarly floppy disks have been disappeared except their usage in some instances. CDs and even DVDs are rare in compared to Blu-ray disks. Yet, the importance of RAM still exists. Moreover,with the arrival of online cloud storage the necessity of physical storage devices in personal usage reduces gradually.

Characteristics of computer storage devices

Storage Capacity

The storage capacity is a decisive factor of a storage device. For example the storage capacity of of flash storage devices is less than that of magnetic storage devices. The storage capacity also depends on the purpose of that particular storage device. For example the memory registers store minute information like memory locations that hold data (references) while the hard disk is capable of storing a large capacity of data and information.

Access speed

This element is quite connected with the feature of storage capacity. When the storage capacity of a device increases, the time the CPU takes to access its data increases respectively. For instance, the CPU takes less time to access memory registers than the time it takes to access the RAM.

Cost/ price

The cost becomes a predominant factor in purchasing a storage device. The cost of a storage device depends on its features and its purpose. If it is a portable device, sometimes ther is a difference of the price. For example, the external hard disk is more expensive than the internal hard disk. Sometimes, the cost depends on the access speed of the device. When the access speed increases the cost is increased respectively.

References

Christensson, P. (2014, October 20). DVD Definition. Retrieved from Tech Terms.com: https://techterms-com.cdn.ampproject.org/v/s/techterms.com/amp/definition/dvd?amp_js_v=a6&amp_gsa=1&usqp=mq331AQKKAFQArABIIACAw%3D%3D#aoh=16345397694700&referrer=https%3A%2F%2Fwww.google.com&amp_tf=From%20%251%24s&ampshare=https%3A%2F%2Ftechterms.com%2Fde

Goodman, P. (2021, January 08). Computer Basics: 10 Examples of Storage Devices for Digital Data. Retrieved from Turbo Future: https://turbofuture.com/computers/Examples-of-Data-Storage-Devices

Off line Storage. (2017, 04 26). Retrieved from Computer Hope: https://www.computerhope.com/jargon/o/offlstor.htm

Singh, V. (2020, May 20). Top 10 Cloud Storage & File-Sharing Services for 2020. Retrieved from Cloud Academy: https://cloudacademy.com/blog/top-10-cloud-storage-file-sharing-services-for-2020/

Storage Device. (2020, August 17). Retrieved from techopedia: https://www.techopedia.com/definition/1119/storage-device

Teritory Storage. (n.d.). Retrieved from Science Direct: https://www.sciencedirect.com/topics/computer-science/tertiary-storage