Computer Storage devices
What is a storage device ?
Storage device is a computer hardware that is used in computers to store data.We use the storege devices to store,port or extract data files and objects. These devices can store data both temporarily and permanently. Storage devices can be internal or external to a computer. And these devices provide one of the core functions of the modern computers.
Storage devices store almost all data and applications on a computer, exept for hardware firmware, wich is usually managed separately via ROM. Storage devices are available in variety of sizes depending on the type of device underlying. As example, the standard computers have several storage devices including hard disk, cache and RAM. Not only that, the same device may also have external connected USB drives and optical disk drives.
(Storage Device, 2020)
There are 4 types of storage devices. They are
01. Primary storage
02. Secondary storage
03. Tertiary storage
04. Off-line storage
Then we take a look at these four categories.
01.Primary storage
Primary storage is also known as “Main memory”. The main memory is directly or indirectly connected to the central processing unit via a memory bus. Primary storage is the part of the computer that stores current data, programs, and instructions.The motherboard houses the primary storage. As a result, data from and to main storage may be read and written very fast. This allows the CPU to quickly access the data and instructions stored in the main storage.
As Example:
01. RAM
02. ROM
03. Cache
ROM, which is non-volatile, and RAM, which is volatile, are the two basic forms of primary storage. Even after the computer is turned off, non-volatile memory retains its contents
RAM
Because any data in RAM may be accessed just as quickly as any other data, it’s called Random Access Memory. The primary storage medium is volatile random access memory (RAM). The data and instructions stored in RAM are lost when the machine is turned off. Because data and instructions may be stored and accessed from any point within the memory, RAM is referred to as ‘random access.’
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 contemporary PC.
RAM may have its contents updated at any moment by overwriting it with new data and instructions. A user could, for example, shut one document and open another or start a new program. A computer’s RAM determines how much data and program instructions it can hold at any given time. Unlike other types of primary storage, RAM can be easily upgraded.
RAM is divided into two categories:
01. DRAM (Dynamic Random Access Memory)
02. SRAM (Static Random Access Memory)
Differences between SRAM and DRAM:
ROM
ROM 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 Basic Input Output System is an example of a program that is stored in ROM. It runs as soon as the computer is switched on and checks that the hardware is functioning correctly then loads the computer’s operating system. Because the Basic Input Output System is always needed it is stored in ROM.
Cache
Cache is a high-speed access area that can be either a reserved section of main memory or a storage device. Most computers today come with L3 cache and L2 cache, while older computers included only L1 cache. Data can be transported to and from cache memory much faster than data can be sent to and from RAM. As a result, cache memory is utilized to store data and instructions that are likely to be reused by the processor. Because the processor doesn’t have to wait for data and instructions to be fetched from RAM, processing is faster. The faster a computer runs, the more cache memory it has. Cache memory, on the other hand, is more expensive to manufacture than RAM because of its high-speed capabilities. As a result, cache memory is usually quite little.
Different forms of caching exist to solve this problem: Level 1 (L1) cache and Level 2 (L2) cache. The L1 cache is small in size yet has incredibly rapid transmission rates. L1 cache is utilized by the processor to store the most frequently used instructions and data. L2 cache has a larger capacity than L1 cache, however it is slower. It’s used to store data and instructions that aren’t used too often.
02.Secondary storage
Secondary storage is long-term, non-volatile storage. All programs and data would be lost if the computer was switched off without secondary storage. It is not directly accessible by the CPU. Computer usually uses its input/output channels to access secondary storage and transfers the desired data using intermediate area in primary storage.
In a computer system, there are three types of secondary storage:
01. solid state storage devices
02. optical storage devices
03.magnetic storage devices
Example for secondary storage:
Hard Disk
Hard Disk
The hard disk drive is the main, and usually largest, data storage device in a computer. It can store anywhere from 160 gigabytes to 2 terabytes. 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 two directions. A disk drive uses read/write heads containing electromagnets to create magnetic charges on the medium.
There are two types of Hard Disks as internal Hard Disks and External Hard Disks.
Internal Hard Disk:
External Hard Disk:
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. Tertiary storage, sometimes known as tertiary memory is a level below secondary storage. Typically, it entails a robotic mechanism that will mount (insert) and dismount removable mass storage media into a storage device in accordance with the system’s requirements; such data are frequently duplicated to secondary storage before usage. Because it is substantially slower than secondary storage , it is mostly used for storing seldom accessed material. This is primarily useful for extremely massive data storage that are accessible without the assistance of human operators. Tape libraries and optical jukeboxes are two common examples. When a computer needs to read data from tertiary storage, it first consults a catalog database to discover which tape or disc has the data. The computer will then direct a robotic arm to retrieve the media and place it in a drive. When the computer has completed reading the data, the robotic arm will return the medium to its original location in the library.Tertiary storage is also referred to as nearline storage since it is “close to online.” The following is the formal distinction between online, nearline, and offline storage.
Example :
Magnatic tape , Optical disc
Magnatic 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 backup.
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 Blu-ray Disc (BD) ,Compact Disc (CD) and Digital Versatile Disc (DVD)
04.Offline Storage
Also known as disconnected storage. Is a computer data 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. Most secondary and tertiary storage media in current personal computers are also utilized for off-line storage. Optical discs and flash memory devices are the most prevalent, with detachable hard disk drives a distant second. Magnetic tape is the most commonly used medium in enterprise.
Example : Floppy Disk , Zip diskette , USB Flash drive , Memory card
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 data 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 100 MB of data or 250 MB 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 information. 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.
Computer storage devices
There are 4 types of computer storage devices.
01. Magnetic storage devices
02. Optical storage devices
03. Flash Memory devices
04. Online Cloud storage devices
01.Magnetic storage devices
Magnetic storage stores data by storing different patterns of magnetization on a magnetically coated surface. Magnetic storage is a non-volatile storage. One or more read/write heads, which may contain one or more recording transducers, are used to access the information. Because a read/write head only covers a part of the surface, data must be accessed by moving the head, medium, or both. Magnetic storage in modern computers will take the following forms:
· The magnetic disk
· Floppy disk
· Hard disk drive.
· Magnetic tape.
· Memory of a carousel (magnetic rolls)
02.Optical storage devices
The typical optical disc stores information in distortions on the surface of a circular disc and reads it by illuminating the surface with a laser diode and observing the reflection. Storage on optical discs is non-volatile. Deformities can be permanent (read-only media), formed just once (write-once media), or reversible (recordable or read/write media). The following are the most commonly used forms right now:
CD, CD-ROM, DVD, BD-ROM: Read only storage, used for mass distribution of digital information (music, video, computer programs)
CD-R, DVD-R, DVD+R, BD-R: Write once storage, used for tertiary and off-line storage
CD-RW, DVD-RW, DVD+RW, DVD-RAM, BD-RE: Slow write, fast read storage, used for tertiary and off-line storage
Ultra Density Optical or UDO is similar in capacity to BD-R or BD-RE and is slow write, fast read storage used for tertiary and off-line storage.
(wikipedia, 2021)
03.Flash Memory devices
Any sort of drive, repository, or system that uses flash memory to store data for an extended period of time is referred to as flash storage. Flash memory is now widely used in small computing devices as well as large enterprise storage systems. The size and complexity of flash-based storage vary from portable USB drives through smartphones, cameras, and embedded systems to enterprise-class all-flash arrays (AFAs). Flash is available in a variety of formats for various storage applications and is typically referred to as solid-state storage due to the lack of moving parts. (Flash storage, Teach target, 2021)
05.Online Cloud storage devices
Cloud storage is a computer data storage strategy in which digital data is kept in logical pools that are referred to as “the cloud.” Physical storage is often spread over numerous servers (possibly in various regions), and the physical environment is typically owned and maintained by a hosting business. These cloud storage providers are in charge of maintaining the data available and accessible, as well as keeping the physical environment secure, protected, and operational. People and businesses purchase or lease storage capacity from providers in order to store user, organization, or application data. Cloud storage services can be accessed via a colocated cloud computing service, a web service application programming interface (API), or through Application programming interface apps such as cloud desktop storage, a cloud storage gateway, or Web-based content management systems. (wikipedia, 2021)
Example :
DropBox, iCloud, Google Drive, Microsoft, One Drive, Idrive, Mega, Box, pCloud, Tresorit, Amazon Drive
Most used storage devices
Here are some of the most common devices used to store digital data and transfer it between computers.
- Hard Disk Drives.
- Floppy Disks.
- Tapes.
- Compact Discs
- DVD and Blu-ray Discs.
- USB Flash Drives.
- Secure Digital Cards
- Solid-State Drives
- Cloud Storage
- Punch Cards
References
Computer data storage, WIKIPEDIA. (2021). Retrieved from WIKIPEDIA: https://en.wikipedia.org/wiki/Computer_data_storage#Tertiary_storage
Flash storage, Teach target. (2021). Retrieved from Teach target: https://searchstorage.techtarget.com/definition/flash-storage
Java T Point. (2021). Retrieved from Java T Point: https://www.javatpoint.com/hard-disk-definition-and-functio
Memory and storage, Bite site. (2021). Retrieved from Bite site: https://www.bbc.co.uk/bitesize/guides/zfssv9q/revision/4
Storage Device. (2020, August 17). Retrieved from Techopedia: https://www.techopedia.com/definition/1119/storage-device
Storege devices, Turbo future. (n.d.). Retrieved from https://turbofuture.com/computers/Examples-of-Data-Storage-Devices
wikipedia. (2021). Retrieved from wikipedia: https://en.wikipedia.org/wiki/Computer_data_storage#Magnetic
wikipedia. (2021). Retrieved from wikipedia: https://en.wikipedia.org/wiki/Cloud_storage