Storage devices: types, volume, technologies

A computer is a device in which there can be many components. Each of them is responsible for a specific task. The processor is considered the “brain” of the system and works with computational algorithms. The power supply is the “heart” of the PC, which supplies electricity to the board.
But the storage device is responsible for computer memory. It can be different in shape, type, volume and other parameters.


Definition of storage device

Speaking of a data storage device, it is computer memory that unites each of them. It can be represented by a physical device or storage medium. Used in calculations for a certain time.
Ever since the release of the first PC, the memory paired with the processor remained unchanged components. Since then it has been presented as a kind of hierarchy and requires the use of several storage devices.

Memory tasks

Depending on the type of storage device, their tasks may vary. But they have a common goal – the storage of the state of external influence. This happens in separate cells. That is how the data is written.
Functionally, such cells have a similar mechanism with a switch. Data is recorded in two understandable states – 1 and 0. They indicate on and off, respectively.

Data access

To have access to the cells of PC storage devices, special equipment is needed. It provides arbitrary and sequential reading.
The process itself can be divided in time. Users are aware of the write and read operations. In order for the process to work correctly, a special mechanism is allocated for it – a memory controller. In addition to writing and reading, there is also an erase process.
In this case, the algorithm is configured so that the mechanism begins to enter the same values.

storage devices Data access

Storage devices

Computer storage devices are improving over time. Some replace others. But the hard drive remains unchanged. Without it, the system will not be able to fully function, if only because there will be no free space for installing the operating system.
No less important in a modern personal computer is RAM. Its modules are an integral part of the system, as they are engaged in the storage of temporary data.
Even 10 years ago floppy disks were considered popular. Modern adolescents no longer know about this device, but it can still be attributed to those that store data.
One cannot help but recall CDs and DVDs. And although on the streets and in stalls they still sell CDs with films and music, they have long lost their relevance. And manufacturers are slowly saving users from optical drives.
A device for long-term storage of data is considered to be flash memory. These include memory cards, flash drives and other solid state mechanisms. It’s not easy without them now, because a constant exchange of information is required, and the one that is available on a PC is not always enough.

Storage Devices Functions

To understand the storage and processing devices, you need to understand the functions of memory. Its main parameter is the long-term storage of information. It is for this that the same hard drive or flash cards serve.
Those familiar with programming have heard of von Neumann architecture. It is the basis of the work of any modern computer. And memory and the central processor are key tools.
At one time, memory was used to store recorded data. The programs of the storage devices worked only according to a clear algorithm of the executed sequences. At that time, any work with programming took not only a huge amount of time, but also required a significant amount of manual work.
All this managed to be accelerated due to von Neumann architecture. Any data is converted to bits. Therefore, it became absolutely unimportant how the information was presented. In any case, it could be converted to bit strings or binary numbers.
Due to the emergence of storage devices for programs and data, it has become possible to manipulate data. But for this it would be necessary to provide sufficient storage system capacity.
Now the functionality of all such devices is almost the same. But they still differ from each other. Therefore, they have their own advantages and disadvantages. Until it turned out to develop a universal device, several types of computers work at once in computers.


Dealing with the types of storage devices is not easy. At the moment, there is no established classification that would be documented. Therefore, some types of memory can be in several groups at once.


There is the concept of classification of memory, as well as classification of storage device. In the first case, for differentiation, it is necessary to understand the parameters, but in the second, technical implementation.

Memory classification So, many are used to the fact that storage devices are usually represented by a physical device. They can have different shapes, dimensions and weights. But this does not apply to the memory itself.
In this case, it is necessary to consider it by the following parameters:

  • operations
  • access
  • data organization and algorithms
  • appointment
  • address space, etc.

As already mentioned, memory allows two basic operations: reading and writing. So there are some devices that provide read-only or both.
Access can also characterize memory. It is consistent and arbitrary. The first option (SAM) gives sequential access: cell by cell are read as they are located. The second option (RAM) provides information from any cell, regardless of its location.
Data organization is a memory parameter and can also be classified according to the classification of data structures. Therefore, there is an addressable, associative, store, semantic, object, etc.
By appointment, the memory can be:

  • buffer – for temporary storage or exchange
  • temporary – for intermediate results
  • cache – for storing frequently used data, for quick access to it
  • corrective – to store addresses where you can find faulty cells
  • manager – for the operation of the corresponding firmware
  • Shared – for sharing.

Address space is another parameter of memory functionality. It happens real – its addressing leads to physical storage; virtual – addressing does not have a physical data location; overlay – areas have the same addresses, so at every moment access is only to one of them.

Storage Classification

A storage device (memory) implements computer memory, and accordingly its functionality. It can be classified in different directions. Among the main ones it is worth noting:

  • form of information
  • the ability to record
  • appointment
  • volatility
  • type of access
  • geometric design.

The storage device for programs and data may be analog or digital in the form of information. Almost all modern mechanisms belong to the latter option.
Whenever possible, recordings distinguish between devices on which information was recorded by the manufacturer. There are also mechanisms that allow you to save data using a separate device. The latest memory option – those that allow any owner to store information (all modern drives).
By purpose, several device options can be distinguished:

  • Random access memory – temporary data
  • internal – for long-term storage of information
  • external – for backup storage or file transfer
  • devices for identification and payments.

Few know, but the computer has non-volatile memory. This is a storage device that does not lose files after a power outage. This includes the hard drive. But volatile PC memory is considered operational, which erases all processes after turning off the system.
The access type of the information storage device can be sequential (magnetic tape), arbitrary (random access memory), direct (hard disk), and associative (database devices).
Finally, the geometric design distinguish between disk, tape, drum, card and printed memory.

Hard Disk Drive (HDD)

Since this is a computer device for storing programs and data, it is worth starting with a hard drive. Winchester is already an interchangeable, but no less popular part of the system. It has served since the birth of computer systems.

Hard Disk Drive

It is based on magnetic recording and has direct access to data. Information in this case is recorded on aluminum plates. Reading is due to the reading head

To distinguish the hard drive from other memory, it is worthwhile to understand its characteristics. Some of them are found in all other devices, and some are special.
The first thing that needs to be done for the railway to work is to connect it. Therefore, one of the main parameters is the interface. Thanks to him, two devices can interact. Now almost all hard drives in home computers are connected using SATA.
The next important parameter of a hard disk is its capacity. It helps determine the amount of data that will be stored on the device. This parameter affects the choice of the buyer. At the moment, the maximum volume is about 10 TB. It is usually used for server systems. For home PCs, users buy hard drives from 200 GB or more.
The form factor characterizes the physical size of the hard drive. 3.5-inch models are installed on computers, and 2.5 on laptops.
An equally important parameter for the fast operation of the hard drive is random access time. It is on this parameter that hard drives lose solid state. The average result is 8-10 ms. For server drives, the figure can be from 2 ms, and for home PCs – up to 16 ms.
This parameter depends on one more thing – spindle speed. Measured in revolutions per minute. Optimum for an average PC is considered an indicator of 5200 rpm. For server systems, it can exceed 10,000 rpm.
Among the parameters of this computer device for storing programs and data, it is worth noting reliability, the number of input and output operations, energy consumption, shock resistance, etc.

Solid State Drives (SSD)

This is another storage device. What to choose better – SSD or HDD? This is a very popular question and many have long answered it. It is important to understand the purpose of the system and its performance. To decide on this issue, it is worth considering a solid-state drive in comparison with a hard disk.
Not so long ago appeared SSD. It is believed that the device has replaced the hard drive. But so far it has not been able to completely replace it. And everything in it is good, except for the price.
This is a non-mechanical memory device that operates on the basis of microcircuits. Thanks to this, it was possible to achieve high speed. Compared to a hard drive, an SSD is compact and lightweight.

Solid State Drives

Its main advantage is speed. If the average random access indicator in the HDD is 8-10 ms, then in the SSD it is 1 ms. Accordingly, the device is 8-10 times faster. And this cannot be overlooked while working with it.
The main advantages of this modern data storage device are:

  • silent work
  • mechanical resistance
  • stability
  • read and write speed
  • low power consumption
  • compact size, etc.

But not everything is so smooth. Despite the obvious advantages, the solid state drive has its disadvantages:

  • limitation in the number of recording cycles
  • cost
  • complexity of data recovery
  • probability of failure of electronic elements
  • budget models have low performance, etc.

Choosing between HDD and SSD

Both software storage devices are good in their own way. Therefore, many decided not to make such a difficult choice in favor of one or the other option. Therefore, users prefer to install both drives in gaming computers. At the same time, it is recommended that the system itself be loaded onto the SSD so that it loads faster.
In online stores you can also find HDD / SSD hybrids. But there are not so many options as if you select each device individually.
It is also worth paying attention to the cost.


Many believe that RAM does not apply to storage devices. This is a false statement. RAM is part of computer memory and does not store user files, but machine code and data that the processor processes. As mentioned earlier, this is non-volatile memory.
In most modern computers, RAM is represented by dynamic memory modules that provide random access. It should immediately be said that dynamic memory is currently considered cheaper than static. This is due to the denser placement of cells on the crystal.
Dynamic memory (DRAM) uses a single capacitor and transistor. Therefore, this type is considered both cheaper and more economical. Its disadvantage is slow operation and problems with charging the capacitor.


Static memory (SRAM) has a high speed. But due to the special structure, its cost is high. The device is not found on regular PCs.
You can find dynamic memory modules in your home computer. When choosing it, the user first of all look at the volume. A storage device can have from 1 to 64 GB. For the gaming system, many choose the option of 16 GB. Moreover, it can be implemented with one or two modules or even four.
Also, special attention should be paid to the type of memory. Depending on it, it can work faster. The latest is considered DDR4 with a frequency range from 1600 to 3200 MHz. This is the best option for modern systems. Although still some prefer the outdated DDR3. But most likely it will soon be withdrawn from production, as everyone has long been talking about the release of DDR5.
In addition to the operating frequency, it is recommended to look at the timing indicators. This indicator characterizes the operating time of the chips with the bank. The lower the indicators, the faster RAM works.

Network drives

They are usually rarely recognized about them, since such devices are designed for special tasks. They are very expensive, bulky and are usually used in special organizations.
NAS is a network storage device. It has a lot of advantages. For example, the connection is not through a PC, but through a router. Thus, you can provide access to data from any device that is connected to this network.
It is worth saying right away that such a device requires a processor and RAM for operation. Therefore, the NAS can be safely called a separate computer. The capacity of such a system can be from 4 to 24 TB.
Such network drives can vary significantly in size and purpose. Some may become a family media center. The device works in an Ethernet environment.

Network Attached Storage (NAS)

NAS provides access to data and its management. Sometimes this option is chosen as your own cloud system. Typically, the device is used by those who need:

  • inexpensive drives of medium capacity
  • convenient installation and configuration
  • remote access; streaming support
  • access from multiple devices
  • automatic backup, etc.


This is a removable storage device that was popular 10 years ago. The medium was used for repeated writing and reading. To read the information, it was necessary to place the diskette in the drive.
By 2018, it will be difficult to find a person who would use such a drive. This is due to its limited volume and inconvenience of use. Yes, and motherboard manufacturers have long ceased to place a special interface for connecting a drive.
Sometimes floppy disks can be found in obsolete production, be it industry or medicine. To be able to work with drives, there are even special emulators.
Almost completely, this removable storage device has been completely replaced with flash drives. They are more reliable, have a much larger volume and high speed.

CD and DVD

These are optical storage media. We have known them for a long time. Even 10-15 years ago they were at the peak of popularity. But after the active development of flash memory, they began to forget about them. Although at one time they could be considered the main device for long-term data storage. Many even now have discs, photos, music and films hidden on their discs.
Initially, the CD appeared as a drive that was supposed to store audio files. But very quickly they began to use it to store any data. Over time, CD-R appeared, which allowed not only to read, but also to write data. But CD-RW allowed to do this repeatedly.
The DVD has become a development of the CD. It looked almost the same, but had a denser structure. This meant that the amount of stored information became larger. This format was needed to replace video tapes. Therefore, it was assumed that films could be recorded on it. Later it turned out that it can store data in various formats.

CD and DVD

The popularity of CDs is not as deplorable as floppy disks. Nevertheless, every year it is becoming smaller. This is due to the fact that operating systems require more resources. Programs have become heavier, as have audio and video files. Since compact discs have a limited capacity, they become useless.
For example, the image size of Ubuntu has long exceeded 700 MB. Windows 7 stopped supporting system installation from the CD. Music players became more compact, which means they got rid of drives.
The materials from which the compact discs are made have reduced wear resistance. When scratches appear on the plates, some information is lost and data reading becomes impossible.

Flash memory

This is one of the popular types of peripheral storage device. It is a semiconductor technology, thanks to which a re-programmable memory is obtained.
Flash memory can be attributed to a solid-state drive, which was mentioned above. Well, the most popular devices of this type are flash drives.
It is believed that the USB-flash drive replaced the floppy disks. This is a storage device that connects to a computer via a USB interface. This peripheral storage device is much smaller than an optical disk. It allows not only reading, but also multiple rewriting of information.
The main task of the flash drive is storage, transfer, file sharing, backup, boot systems, etc. The device consists directly of a USB interface, a controller, an oscillator and a NAND chip, which stores information.
In most cases, a special file system is used. The most popular is the FAT family. If the flash drive has a capacity of more than 64 GB, then it is customary to format it into the NTFS file system.
Of course, such a storage device has both advantages and disadvantages. The advantages include:

  • compact size and weight;
  • silent work and portability;
  • use of a universal interface (a USB flash drive can be connected to a PC, TV, tablet, consoles and other devices);
  • low power consumption; resistance to mechanical interactions and magnetic fields;
  • long-term storage of data offline.

The disadvantages of a USB flash drive include:

a limited number of write cycles, as in any other flash device;
Speed ​​limit due to USB bandwidth
sensitive to radiation and electrostatic discharge.

The very first flash drive appeared in 2000. Since then, it is only gaining popularity. And although now it is one of the main ways of transmitting and exchanging data, you should not underestimate the benefits of the device.

Flash Drive

Every year the cost of flash drives decreases. They become more capacious and faster. At the peak of the popularity of devices, manufacturers decided to focus on design. So there was a huge number of diverse shapes and sizes. There are plush flash drives, and very small. They have the appearance of their favorite characters in films and cartoons. In the online store you can find a flash drive in the form of a roll or a donut. All this is necessary in order to somehow attract the attention of the buyer.

Memory card

This is another flash drive, which is worth telling separately. It is a compact external storage device that allows you to read and write digital information. Despite the fact that many of them are built on the basis of flash memory, they can use completely different technologies.
Memory cards are rarely used for backup data storage and exchange between PCs. Due to their compact size, they can be lost. Therefore, they began to be used wherever space was needed. Flash cards hit cameras and cameras, smartphones and tablets, players and other gadgets.
In the early 1990s, PC Card appeared, which are now found in network cards, modems and hard drives. Digital cameras and telephones needed similar cards. But only in 2001 did SM and CF become known. Within a couple of years, they were replaced by SD / MMC.
In 2013, SDHC became known. These flash cards, in addition to reading and writing data, made it possible to transfer them directly from one device to another, without connecting. Photographers, who no longer needed to connect the camera to a PC and transfer data, were incredibly happy with this invention. It was enough to use a Wi-Fi network.


It is not enough to talk about past and present information storage devices. A lot is ahead of us. The prospects for developing new types of memory are bright. Now we are aware of several technologies that will need to increase the volume and speed of data transfer.
RRAM is non-volatile memory. It is currently under development. Experts have found that if a high voltage is applied to the dielectrics, low resistance filaments appear inside them. Thus they turn into conductors. At the same time, high voltage can both destroy these threads and create them again.
At the moment, this option has not been finalized. There are many problems to solve. But if everything succeeds, then the buyer will receive a high-speed memory. In addition, the technology will allow you to overlay memory in layers, which means to develop ultra-high-capacity modules.


Running memory is another non-volatile memory. The essence of this technology is built on the reduced size of magnetic domains 10 years ago. The developers plan to organize the movement of domains in nanotubes using spintronics.
This option also implies a significant increase in memory density. At the same time, technology will help ensure high speed reading and writing.
Nano-RAM is a computer memory technology. It is based on the work of carbon nanotubes. Due to the compactness of the nanotubes, it will be possible to achieve a high recording density.
In addition, energy can be reduced with technology. Therefore, it is more likely that Nano-RAM will be needed in smartphones and tablets, where battery conservation is an important thing.

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