Computer Storage Devices
Definition of computer storage devices:
The storage device is a hardware device that is used to store data and information. They Provide one of the core functions of the modern computer. Every desktop computer, laptop, smartphone, and tablet will have some kind of storage device within it. It can be inside or outside of the computer or the main device. They come in different sizes and shapes depending on the needs and functionalities.
The usage of storage devices:
The storage devices are used to store data mainly bn the people. Storage devices, such as hard disk drives and USB flash drives, are used to store application and user data. This storage is persistent, it doesn’t forget the data it is storing even when the computer is turned off. As well as the store our files and application on our devices so we can use them, storage is also important for backup and recovery, should our data be harmed. There are a number of technologies that are particularly useful for this. (Storage Devices, n.d.)
Characteristics of computer storage devices
Storage technologies at all levels of the storage hierarchy can be differentiated by evaluating certain core characteristics. These core characteristics are,
· Volatility: Whether the stored data will remain or not when the power supply is disconnected.
· Differentiation: Whether it’s a Dynamic random access memory or static memory.
· Accessibility: Whether it’s Random-access or Sequential access
· Addressability: Whether it’s a Location-addressable, File addressable, or Content-addressable.
· Mutability: Whether it’s a Read/write storage or mutable storage, Read-only storage, or a Slow write, fast read storage.
(Computer Memory: Characteristics of Storage, n.d.)
Types of storage:
Primary storage
A primary storage device is any storage device or component that can store nonvolatile data in computers, servers, and other computing devices. It is used to hold/store data and applications temporarily or for a shorter period of time while the computer is running. These are the fastest of the memory/storage device category. Primary storage is also known as main storage, main memory, or internal memory. (What is Primary Storage Device?, n.d.)
Primary storage is directly or indirectly connected to the central processing unit via a memory bus. The CPU continuously reads instructions stored there and executes them as required. (Ford, 2021). Examples for primary memory are RAM, ROM, and Cache memory.
RAM
This is called Random Access Memory because any of the data in RAM can be accessed just as fast as any of the other data. This is generally located on the motherboard of the computer. RAM is a volatile type of memory, meaning that all information that was stored in RAM is lost when the computer is turned off. Volatile memory means temporary memory. (Chakraborty, 2021)
There are two types of RAMs,
· DRAM (Dynamic Random Access Memory)
Dynamic RAM is a memory that needs refreshing. The refreshing is done by the memory controller which is part of the chipset on the motherboard. DRAMs are usually smaller and less expensive than SRAMs and are used in practically every PC. (Chakraborty, 2021)
· SRAM (Static Random Access Memory)
Static RAM (SRAM) is volatile memory and is often used in cache memory and registers because it is a lot faster and does not require refreshing like Dynamic RAM. As long as power is supplied, SRAM retains its content and there’s no need to refresh it on a regular basis. (Chakraborty, 2021)
ROM
This is called Read-Only Memory. 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 is non-volatile, so ROM memory cannot be easily or quickly overwritten or modified. ROM performs major input/output tasks and holds programs or software instructions. (What is Read-Only Memory (ROM)?, 2020)
Cache memory
The cache is a high-speed access area that can be either a reserved section of main memory or a storage device. Cache memory provides faster data storage and access by storing instances of programs and data routinely accessed by the processor. Thus, when a processor requests data that already has an instance in the cache memory, it does not need to go to the main memory or the hard disk to fetch the data. (What is Cache Memory?, 2021)
Secondary storage
Secondary memory is not directly accessible by the CPU. The computer usually uses its input/output channels to access secondary storage and transfers the desired data using an intermediate area in primary storage. Typically, secondary storage allows for the storage of data ranging from a few megabytes to petabytes. These devices store virtually all programs and applications stored on a computer, including the operating system, device drivers, applications, and general user data. (What is a Secondary Storage Device?, 2020)
Hard disk is an example for secondary storage.
Tertiary Storage
Typically, it involves a robotic mechanism that 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. Examples for tertiary storage are,
· Magnetic Tape
· Optical Disk
Offline Storage
The offline storage device is a storage device that is not currently online, live, or connected to the computer. These are also called disconnected storage. The data stored in offline storage remains permanently in the storage device even if it’s disconnected or unplugged from the computer after the data has been stored. Offline storage is generally portable in nature and can be used on different computer systems. (What is Ofline Storage?, n.d.)
Examples for offline storage are,
· Floppy Disk
· Zip Diskette
· USB Flash Drive
· Memory Card
Types of computer storage devices
There are four types of computer storage devices,
Magnetic storage devices
Hard Disk
A hard disk drive (HDD) is a non-volatile computer storage device containing magnetic disks or platters rotating at high speeds. Typically, it spins at 5,400 to 15,000 RPM. The disk moves at an accelerated rate, allowing data to be accessed immediately. When the platters rotate, an arm with a read/write head extends across the platters. The arm writes new data to the platters and reads new data from them. All data is stored magnetically, allowing information to be saved when power is shut off. (What is Hard Disk Drive (HDD)?, 2016)
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.
In the present, there are mainly two types of hard drives,
· Internal Hard disk
· External Hard disk
· Magnetic tape
Magnetic tape is a magnetically coated strip of plastic on which data can be encoded. Magnetic tapes of computers are similar to tapes used to store music. These are much less expensive than other storage mediums but are commonly a much slower solution that is commonly used for backup.
· Floppy Disk
A Floppy disk is a portable soft magnetic disk. These are slower to access than hard disks and have less storage capacity, but they are much less expensive. These can store data up to 1.44 MB. The two common sizes of floppy disks are 5 ¼” and 3 ½”.
· Zip Diskette
Zip Diskette is a hardware data storage device developed by Iomega that functions like a Standard 1.44" floppy drive. These are capable to hold up to 100 MB of data or 250 MB of data on new drives. But these are now less popular as users needed larger storage capabilities and the Zip diskette can fulfill that need.
Optical storage devices
· Blu-ray Disc (BD)
· Compact Disc (CD)
· Digital Versatile Disc (DVD)
Optical devices use a laser to scan the surface of a spinning disc made from metal and plastic. The disc surface is divided into tracks, with each track containing many flat areas and hollows. The flat areas are known as lands and the hollows as pits. When the laser shines on the disc surface, lands reflect the light back, whereas pits scatter the laser beam. A sensor looks for the reflected light. Reflected light (lands) represents a binary ‘1’, and no reflection (pits) represents a binary ‘0’. (Common types of secondary storage, n.d.)
Flash Memory devices
Flash memory is a non-volatile memory chip used for storage and transferring data between a personal computer (PC) and digital devices. It has the ability to be electronically reprogrammed and erased. It is often found in USB flash drives, MP3 players, digital cameras, and solid-state drives. (What is Flash Memory?, 2018)
Some examples for flash memory devices are,
· USB Flash Drive
USB means Universal Serial Bus. This is a small, portable flash memory card that plugs into a computer’s USB port and functions as a portable hard drive. USB Flash Drives are typically rewritable devices. Flash drives are available in sizes such as 2GB, 4GB, and up to 256GB and are an easy way to transfer and store information. USB drives are commonly used for storage, transferring files between devices, and data backup.
· Memory Card
A memory card is 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. These are usually read by connecting the device containing the card to the computer, or by using a USB card reader. Memory cards are available in sizes such as 2GB, 4GB, and up to 256GB.
Online Cloud storage devices
Cloud storage is a cloud computing model in which data is stored on remote servers and accessed over the internet or through a dedicated private network connection. The storage infrastructure is maintained, operated, and managed by the cloud storage service provider. (What is Cloud Storage?, 2021)
Dropbox, Google Drive, iCloud, Microsoft One Drive, IDrive are some examples for online cloud storage
Most used storage devices
· Hard disk drives
· Cloud storages
· Flash memory
· Optical drives
· External hard drives
References
Chakraborty, K. (2021, February 23). What is Random Access Memory (RAM)? Retrieved from techopedia: https://www.techopedia.com/definition/24491/random-access-memory-ram
Common types of secondary storage. (n.d.). Retrieved from Bitesize: https://www.bbc.co.uk/bitesize/guides/z67j2nb/revision/2
Computer Memory: Characteristics of Storage. (n.d.). Retrieved from Blogger: http://gonagalamahavidyalaya.blogspot.com/p/characteristics-of-storage.html
Ford, J. (2021, February 4). How are instructions stored in the CPU? Retrieved from AnswerToAll: https://answerstoall.com/science/how-are-instructions-stored-in-the-cpu/
Storage Devices. (n.d.). Retrieved from KNOWITALL NINJA: https://www.knowitallninja.com/lessons/storage-devices-3/
What is a Secondary Storage Device? (2020, August 11). Retrieved from techopedia: https://www.techopedia.com/definition/13265/secondary-storage-device
What is Cache Memory? (2021, August 07). Retrieved from techopedia: https://www.techopedia.com/definition/6307/cache-memory
What is Cloud Storage? (2021, August 31). Retrieved from techopedia: https://www.techopedia.com/definition/26535/cloud-storage
What is Flash Memory? (2018, March 7). Retrieved from techopedia: https://www.techopedia.com/definition/24481/flash-memory
What is Hard Disk Drive (HDD)? (2016, December 8). Retrieved from techopedia: https://www.techopedia.com/definition/5288/hard-disk-drive
What is Ofline Storage? (n.d.). Retrieved from techopedia: https://www.techopedia.com/definition/1102/offline-storage
What is Primary Storage Device? (n.d.). Retrieved from techopedia: https://www.techopedia.com/definition/13097/primary-storage-device
What is Read-Only Memory (ROM)? (2020, August 18). Retrieved from techopedia: https://www.techopedia.com/definition/2804/read-only-memory-rom