Computers, Equipment
SSD - what is it? Types of SSDs. Advantages of SSD in front of HDD
Probably, every person who is familiar with computer technology knows or at least heard about such a device as an SSD-drive. What is it and what role does it play in the computer? In short, SSD is used to record and store personal user data. One can argue that there are hard disks for this. And this statement will be absolutely correct, because these components of the computer perform identical functions. So for what invented the SSD-drive, what is it, how it works and how it differs from a conventional HDD? You can find answers to all these questions in this article.
What is the difference between a hard drive and an SSD hard drive? What is this device and what are the main principles of its operation?
To date, the main place for storing most of the files on the computer is the hard drive. If you disassemble it, you can find a rather fragile mechanism inside. It consists of magnetic plates rotating on a special head. Between these plates moves the carriage, which finds and reads the necessary information. The mechanism of the hard disk resembles a gramophone, but only these functions perform different functions. Unlike the mechanism of the musical apparatus, the drive of the hard drive moves at a speed of several thousand revolutions per minute and performs work related to the copying and recording of information.
As for the SSD-drive, or, as it is called, the solid-state drive, it is used for the same purposes as the hard drive. That only works it completely differently. Inside this device there are no moving elements, and special chips are installed to store information. The solid-state drive is like a large USB flash drive, which can be put in place of a hard drive.
Basic principles of operation of solid-state drives
The memory of SSD-disks consists of special blocks, which are divided into cells, where the necessary data is stored. All would be well, but the main problem arises when you need to remove the existing information or re-write it. The fact is that it is impossible to delete part of the information from one block, but it is necessary to format the entire sector. In this case, the necessary data is stored in the cells of neighboring blocks and only then rewritten to the old place. Suppose you want to save data of 10 KB in size. In this case, the memory block has a capacity of 20 KB, 10 KB of which are already occupied. In this case, the information on the disk is transferred to another location, the whole block is deleted and only then old and new data are recorded. It turns out that for one operation the system performs a few additional actions, which leads to a slowdown and speeds up the wear of the solid-state drive.
To increase the performance of the device, you must use a special program called TRIM, or, as it is sometimes called, a truncation of SSD. What this is and how it works, we will consider further. TRIM is not even an application, but a special command that the operating system sends to a solid state drive to identify unused items. With this function, you can immediately delete unnecessary files, avoiding additional operations with transferring information to neighboring blocks. And this significantly improves SSD performance. But this command is not supported by legacy versions of operating systems. Therefore, to connect TRIM on the computer must be installed Windows 7 or 8, Linux version 2.66.33 or higher.
What does SSD consist of?
Having studied the differences between the two types of information stores, we will dwell in more detail on how SSD SSDs are structured, what kind of devices they are and how they function. In appearance it is an ordinary box with connectors for connection to a computer. In general, SSD-discs for home use are equipped with interfaces Sata, USB 3.0 and PCI-Express, which without any problems provide the necessary speed of writing and reading.
There are no moving mechanical parts in solid state drives. Due to this, they are much more resistant to external factors of influence. For example, a normal HDD-disk is a fragile enough thing, because if during the shaking or falling the reading head touches the magnetic plate, this will lead to the disabling of the carrier. But solid state drives are arranged quite differently. Inside these devices are installed special boards, on which the memory chips and the controller are soldered. Some SSDs are additionally equipped with compact batteries that, in the event of a sudden power outage, provide the cache with additional power, and the data is stored on the main memory chips. Now let's take a closer look at the main components of the solid-state drive.
SSD memory: what is it and what are its main functions?
Most SSDs use NAND, or, as it is also called, flash memory. Such chips are used in conventional flushes, only in solid state drives they are more reliable and have a higher processing speed due to the presence of a controller. Because of their low cost, they are widely used in SSD, due to what these devices have become quite accessible for most users. Another plus of this type of memory is that it is non-volatile and does not require additional power to operate.
In addition to NAND technology, SSDs are sometimes used in solid-state drives. This type of memory has a high speed of writing and reading data due to the use of chips used in creating RAM. It will require constant connection to electricity, so in SSD-disks using RAM, often install additional batteries in the event of a sudden power failure. Due to the high cost of production of these drives, they are rarely found in home PCs and laptops. Basically, RAM-SSDs are used in computer systems of large companies to increase the speed of working with databases.
To date, most drives use NAND memory. Despite this, the data SSD-disks differ from each other by the speed of writing, reading data and cost. It all depends on the chips used in the drive: SLC, TLC or SSD MLC. What is this and what is the difference between them? So different types of flash memory are indicated . The most common technology is MLC, thanks to which two bits of information can be stored in one cell. TLC makes it possible to write as many as 3 bits, but this leads to faster cell deterioration, so this technology is not very popular. The fastest and longest is SLC-memory, with the help of which you can write only one bit of data in each cell. Among the shortcomings can be identified only high cost, which is 2 times higher than the price of SSD MLC.
Controller
The controller is the most important element, without which the SSD can not function. What is it and what is its role, we will find out further. These devices perform work on load sharing between memory blocks, are responsible for reading and writing information, correcting errors and compressing files. The controller resembles a command center where decisions are made related to data processing. It is from this detail that the speed of operation of the solid-state drive and its durability depend. The main component of the controllers is a special microprocessor, on which all the load falls. Also the speed of the device depends on the quality of the firmware.
Quite a few companies are engaged in the production of SSD-disks, because the technology of their manufacture is quite simple and takes less time than creating a classic hard drive. All you need is to purchase memory chips, controllers and motherboards, where everything will fall apart. After that, the design is placed in a beautiful case with a brand logo - and the goods are ready for sale. But the components for solid-state drives themselves have a high price, besides the high costs will require the creation of a controller and high-quality firmware to it. Because of this, the cost of SSD-drives to date is much higher than conventional HDD.
Hybrid SSD HDD
Now let's look at the hybrid SSD HDD. What is this device and what is it intended for? Every year, solid-state drives are gaining increasing popularity. Technologies do not stand still, and standard hard drives are gradually replacing more sophisticated systems. SDD-disks are present in many computers, but they are used as a secondary storage of information, and additional. And all because their cost is much higher compared to conventional hard drives. To compensate for this gap between the two types of drives, a hybrid HDD SSD was created. What kind of device is it and what are its advantages, we will try to consider in more detail.
At the heart of the hybrid drive is the same HDD without any changes. But in the case of these drives are installed more chips with flash memory, which is used as a buffer zone. The information that is most often used is copied to it. This allowed to increase the download speed of some applications and the operating system itself, when compared with conventional hard drives. The maximum amount of flash memory in such a hybrid SSD is 8GB. What did this result in the result? In fact, we have something in between a hard drive and a small solid-state drive. In the buffer memory, you can not download data or install applications. It is used as a reserve for launching priority programs that the user can not control on his own. As for the price, the cost of hybrid drives is lower than the standard SSD, but higher than the HDD, besides they are not very popular in our country, so they are not sold everywhere.
Advantages of Solid State Drive
An integral part of the modern computer is the SSD-drive. What is this device and how it works, we found out, it remains to highlight its main advantages and disadvantages in comparison with conventional HDD. Let's start with the positive aspects of solid-state drives.
The most important advantage of SSD is the incredible speed of reading and writing information. They are several times more productive than hard disks. For example, the processing speed of some drives exceeds 500 MB / s. In practice, this gives faster operation of programs and the operating system itself, which is loaded in a matter of seconds. This is very important, because the current generation of computers has a high performance, which greatly slow down the HDD. But with the advent of new drives, their speed has significantly increased.
The next plus of SSD-devices can be called their higher resistance to external factors. They do not have such a fragile mechanism as the hard drives. Due to this they easily tolerate shaking, vibrations and moderate impacts on the body. These devices will be an excellent solution for laptops. In addition, they better cope with temperature changes.
Another advantage of SSD is its quietness and low power consumption. Due to the fact that there are moving mechanical elements in the hard disks, they emit a certain level of noise. In addition, in working condition HDD have a sufficiently high temperature, so coolers have to rotate in accelerated mode. But all these problems are deprived of SSD, which do not heat up, do not make noise and consume less electricity.
disadvantages
Having estimated all the advantages of solid-state drives, it remains to find out what weaknesses the SSD hard drive has. What are these flaws? The first of these is the high cost of such drives. Despite the simplicity of its design, the manufacture of flash memory chips and controllers is quite a costly affair. But do not be upset about this, because technology is constantly evolving, and gradually the price of these goods is going down. In a couple of years they can easily equal the price of HDD.
After the first drawback, you can select the second. Because of the high cost of solid-state drives have a smaller capacity than hard drives. For example, the memory capacity of some HDDs is 8 TB, while SDDs have reached only 1 TB.
The memory of solid-state drives is short-lived, and after the expiration of a certain number of cycles of rewriting, it fails. Although the current generation of these devices has a large enough line of service, but one must be prepared for the fact that one day the drive will stop working, and it will be problematic to restore the information.
I would like to add that the SSD suffers poorly in electricity jumps. If after one of these voltage drops it burns out, then it will be impossible to obtain data. In the case of a HDD-disk, a certain sector will fail in it, and most of it will remain intact, so that you can extract all the undamaged information.
What should I look for when buying an SSD?
Having studied the information about solid-state drives, many users, probably, wanted to purchase this device for their computer. But do not immediately run to the store and take the first item that comes up. Here are a few tips to help with choosing an SSD.
First you need to pay attention to the amount of SSD. What it is? In other words, this is the amount of built-in flash memory. The higher its value, the more information can be recorded. But you do not need to buy the most expensive products, because solid-state drives are mainly used to install operating systems and applications on them, and the main place of data storage is still the hard drive. Having completed its SSD system only by 60-120 GB, you can achieve a significant increase in the speed of your computer.
Speed of reading and copying plays an important role. The higher it is, the better, but it happens that the motherboard can not disclose the potential of the SSD-disk due to the small bandwidth of the bus. It happens that in old notebooks or PCs there is no sense at all to install smart drives, even after updating the system will work the same as on a regular HDD. Therefore, it is worthwhile to study the configuration of your computer, and afterwards go to the store. SATA3 interfaces have the highest throughput , and for older IDE ports, a special adapter is needed to install the SSD.
The most important component of any solid state drive is the controller. It is this detail that controls all the processes associated with the processing of information. On how much quality it will be made, the longevity of the entire device depends, so it is recommended to give preference to proven and well-proven manufacturers. Leaders in production are SandForce, Marvell, Intel, Indilinx.
In the end, pay attention to the dimensions of the drive. For PC this is not so important, because you can install any SSD in the system unit, and with laptops you may have problems.
Basic rules for the operation of solid state drives
After reviewing the reviews of users and experts, we can conclude that an integral part of a modern computer is an SSD hard drive. What this is and how it works, we have already considered. Now you need to learn how to use it correctly. How strange it sounds, but to understand all the advantages of solid-state drives, you must adhere to a few simple rules.
It is not necessary to fill all available memory to failure. Many people neglect this rule, because SSDs have a considerable price, so users buy small drives and completely download them with the necessary and not very information. But we must remember that if you leave less than 25% of free space, then the processing speed of data will significantly decrease. The fact is that the more memory, the higher the number of free blocks, where you can write data. When the space is too small, the information is distributed to the cells of neighboring blocks, and this leads to a decrease in performance.
It is worth remembering that with solid state drives you can significantly improve the speed of your computer, so they recommend that you install the operating system, applications and demanding games. But as the main storage of information it is worth using HDD. It will be more economical and practical, because they can easily cope with the playback of audio and video files no worse than SSD.
It's best to have one of the latest operating system versions installed on your computer. For example, Windows XP or Vista are poorly optimized for work with solid-state drives and do not support the TRIM command.
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