Data storage is the storage of information through the use of technologies specifically developed to store and make it accessible as needed.
Data storage is the use of recording media to store data using computers or other devices. The most common forms of data storage are file storage, block storage and object storage, each of them suitable for different purposes.
- File storage: Economical and easily structured, data are saved in files and folders. They are usually found on hard drives, which means that they appear exactly the same for the user and on the hard drive.
- Block storage: Data are stored in blocks of uniform size. Although more expensive, complex, and less scalable, block storage is ideal for data that needs to be accessed and modified frequently.
- Object storage: Data is stored as objects with unique metadata and identifiers. Although, in general, this type of storage is less expensive, objects’ storage is only ideal for data that does not require modification.
Data storage refers to non-volatile storage, i.e. the ability to store information persistently with a reasonable probability that the information will remain unchanged for a reasonable period of time.
The RAM memory of a computer is the typical memory that, on the contrary, is volatile. In fact, it is sufficient that there is a power failure that all the information stored in it will be lost.
In order to be able to persistently store information in binary digital format (bit sequence), it is necessary to have a physical medium with the following characteristics:
- Bit sequences can be written to the device at least once;
- Written bit sequences remain unchanged unless a specific modification operation is performed;
- Bit sequences can be read a large number of times without altering them.
Below we describe some physical media that meet these requirements:
An Hard Disk Drive (commonly abbreviated as hard disk and abbreviated as HDD, HD), means a mass storage device of magnetic type that uses one or more magnetized disks to store data (files, programs and operating systems).
The hard disk is a computer storage device and it is one of the types of mass storage devices currently most used, being present in most computers and also in other electronic devices.
The hard disk was invented in 1956 by IBM with the 350 Disk Storage Unit. The first prototype consisted of 50 disks with a diameter of 24 inches (about 60 cm) and could store about 5 megabytes of data. It was the size of a refrigerator, weighing over a ton.
The first PC model produced in 1980, had a capacity of about 5 MB, a diameter of 5.25 inches and was equipped with a stepper motor, one for the rotation of hard disks and a second for the movement of the heads.
In 2007 Albert Fert and Peter Grünberg received the Nobel Prize for Physics as pioneers of the invention of the modern hard disk, i.e. with a storage capacity bigger than gigabytes.
The hard-disk basically consists of one or more fast rotating plates, made of aluminum or glass, coated with ferromagnetic material and two heads for each disk (one on each side), which, during operation “fly” at a distance of a few tens of nanometers from the surface of the disk reading or writing the data. The head is held up by the air moved by the rotation of the discs whose frequency or speed of rotation can exceed 15,000 rpm; currently the standard values of rotation are 4,200, 5,400, 7,200, 10,000 and 15,000 rpm.
The storage or writing of information or data on the surface of the ferromagnetic support basically consists of the transfer of a certain direction to the magnetization of a certain number of domains.
In the past, the reading/writing of the magnetic information was entrusted to inductive heads, miniaturized copper windings capable of detecting, in the reading phase and according to the principle of magnetic induction, the variation of the flux of the static magnetic field as the head passes between one bit and the next of a track containing the bits, or in a dual way to impress a magnetization on the disk during the writing phase.
The evolution that Spintronics has brought to everyone’s homes has been the magneto resistive heads, based on a device, able to vary resistance to the changing of the intensity of the magnetic field. The advantage given by these heads lies in their sensitivity, better than the old inductive ones, and in their very small size, which allows to follow the step of the evolutions towards the nanometer as far as the area of a single bit is concerned.
It has long been the only choice on personal computers, but is experiencing a loss of market share in favor of the latest solid state drives, SSD.
Solid State Drive
A solid-state drive (SSD), in electronics and computing, is a type of semiconductor-based mass storage device that uses solid-state memory (especially flash memory) for data storage.
While the terms “solid state drive” or solid state drive are the correct ones, the term “solid state drive” is inappropriate because there is no magnetic or other type of drive inside the SSD (in fact, there is no moving component in it). The use of the word “disk” comes from the fact that this type of mass storage device performs the same function as the traditional hard disk and is therefore used, in general, to replace it.
Unlike magnetic media such as the hard disk head, it has the ability to store large amounts of data in a non-volatile way, without the use of mechanical parts (plates, heads, motors, etc..) as traditional hard drives do. Most solid state drives use NAND flash memory technology, which allows uniform data distribution and driver “wear”.
An advantageous feature of flash memories is the small physical size, which allows the creation of extremely compact and lightweight SSDs, which can be easily integrated into ultra-thin mobile devices.
Network Attached Storage
The NAS, Network Attached Storage, is a special device that allows you to store and share data over a Wi-Fi or wired network with other devices, such as computers and smartphones. This is because it contains one or more hard disk drives.
In fact, through a router or a network created by the NAS, it is possible for all connected devices to access the data stored in the hard-disks.
In this sense, a NAS becomes a network storage device, like a private cloud that is inside your home or business.
In practice, a NAS is similar to a computer that has specific components and an operating system (usually based on Linux) that allow it to perform specific functions. Mainly, they allow you to store and share data in an optimized way.
Since it’s a 100% computer, every cheap or high-end NAS storage will have a power supply, a CPU, a ram, one or more network modules for both wired and Wi-Fi connections, a memory for the operating system and, most importantly, two or more hard-disks bays. Optionally, it may also have USB inputs usually used to connect external USB hard disks in order to use them as backup drives for the files contained in the NAS’s internal drive, or be shared directly across the network.
Today, Network Attached Storage has some very useful features, such as:
- Set file sharing to multiple levels;
- Protect access to certain folders;
- encrypt your files.
The benefits of NAS devices are many. First of all, a NAS allows you to centralize data storage in a single device accessible to all the nodes of the network, highly specialized for performance; then a NAS allows you to implement RAID (Redundant Array of Independent Disks) schemes, which ensure better management of data security.
In the context of the adoption of this architecture a possible disadvantage, instead, could be the enormous amount of data that passes over the network, as it could the limits of performance and stability of an NFS and of other file systems that can be used on the network.
Today, alongside these physical devices we find an innovative way to store data, the cloud storage.
The definition of cloud storage also analyses the meaning of cloud computing, so to understand what it is you must first clarify this term: cloud computing is the use of computing resources available on demand through the Internet, including data processing and transmission services; specifically, cloud storage is the use of cloud computing for storing files.
Cloud storage is therefore the most widespread technology of cloud computing, thanks to the spread of useful services for the end user.
Cloud Storage is a model of data storage on networked computers where the data itself is stored on multiple virtual servers generally hosted in third-party facilities or on dedicated servers.
Consumers and businesses only pay for the use they make of it, typically a monthly use. This does not mean that cloud storage is cheaper than a hard disk or USB stick, it just means that it consists of operating expenses instead of capital expenditures. In practice, cloud storage is a pure service while using your own means of storage requires expenditure on material goods.
Cloud storage allows you to increase file security and reliability in a single service that stores and encrypts all files on a PC.
Many companies offer free plans for cloud data storage.
However, in terms of size, functionality, management capabilities and service level assurance, free services are often too limited for business use, which may have specific needs depending on the type of use.
Therefore, it is very often recommended for professional business use to purchase cloud storage services that offer more storage space and additional security services.