What is an ssd drive and what is it for. SSD disk - what it is and what it is used with. Disadvantages of modern SSDs
First SSD, or solid state drives using flash memory, appeared in 1995, and were used exclusively in the military and aerospace fields. The huge cost at that time was compensated by unique characteristics that allowed the operation of such disks in aggressive environments over a wide temperature range.
In the mass market, drives SSD appeared not so long ago, but quickly became popular, as they are a modern alternative to a standard hard drive ( HDD ). Let's figure out what parameters you need to choose a solid-state drive by, and what it actually is.
Device
Out of habit, SSD is called a “disk”, but it can rather be called “ solid parallelepiped", since there are no moving parts in it, and nothing shaped like a disk either. The memory in it is based on the physical properties of the conductivity of semiconductors, so SSD– a semiconductor (or solid-state) device, while a regular hard drive can be called an electro-mechanical device.
Abbreviation SSD just means “ solid-state drive ", that is, literally, " solid state drive" It consists of a controller and memory chips.
Controller– the most important part of the device that connects the memory to the computer. Main characteristics SSD– data exchange speed, power consumption, etc. depend on it. The controller has its own microprocessor that works according to a preinstalled program and can perform the functions of correcting code errors, preventing wear, and cleaning debris.
Memory in drives can be either non-volatile ( NAND), and volatile ( RAM).
NAND memory initially won against HDD only in the speed of access to arbitrary memory blocks, and only since 2012 the read/write speed has also increased many times over. Now in the mass market drives SSD are presented by models with non-volatile NAND-memory.
RAM The memory features ultra-fast read and write speeds, and is built on the principles of computer RAM. Such memory is volatile - if there is no power, the data is lost. Typically used in specific areas, such as speeding up work with databases, it is difficult to find on sale.
Differences between SSD and HDD
SSD differs from HDD First of all, the physical device. Thanks to this, it boasts some advantages, but also has a number of serious disadvantages.
Main advantages:
· Performance. Even from the technical characteristics it is clear that the read/write speed is SSD higher by several times, but in practice the performance can vary by 50-100 times.
· No moving parts, and therefore no noise. This also means high resistance to mechanical stress.
· Random memory access speed is much higher. As a result, the speed of operation does not depend on the location of files and their fragmentation.
· Much less vulnerable to electromagnetic fields.
· Small dimensions and weight, low power consumption.
Flaws:
· Resource limitation for rewrite cycles. This means that a single cell can be overwritten a certain number of times - on average, this figure varies from 1,000 to 100,000 times.
· The cost of a gigabyte of volume is still quite high, and exceeds the cost of a regular HDD several times. However, this drawback will disappear over time.
· Difficulty or even impossibility of recovering deleted or lost data due to the hardware command used by the drive TRIM, and with high sensitivity to changes in supply voltage: if memory chips are damaged in this way, information from them is lost forever.
In general, SSDs have a number of advantages that standard hard drives do not have - in cases where performance, access speed, size and resistance to mechanical stress play a major role, SDD persistently displaces HDD.
How much SSD capacity will you need?
The first thing you should pay attention to when choosing SSD– its volume. There are models on sale with capacities from 32 to 2000 GB.The decision depends on the use case - you can install only the operating system on the drive, and be limited by the capacity SSD 60-128 GB, which will be quite enough for Windows and installation of basic programs.
The second option is to use SSD as the main media library, but then you will need a disk with a capacity of 500-1000 GB, which will be quite expensive. This only makes sense if you work with a large number of files that need to be accessed really quickly. In relation to the average user, this is not a very rational price/speed ratio.
But there is one more property of solid-state drives - depending on the volume, the write speed can vary greatly. The larger the disk capacity, the faster the recording speed, as a rule. This is due to the fact that SSD capable of using several memory crystals in parallel at once, and the number of crystals grows along with the volume. That is, in the same models SSD with different capacities of 128 and 480 GB, the difference in speed can vary by about 3 times.
Considering this feature, we can say that now the most optimal choice in terms of price/speed can be called 120-240 GB SSD models, they will be enough to install the system and the most important software, and maybe even for several games.
Interface and form factor
2.5" SSD
The most common form factor SSD is a 2.5 inch format. It is a “bar” with dimensions of approximately 100x70x7mm; they may vary slightly among different manufacturers (±1mm). The interface of 2.5” drives is usually SATA3(6 Gbps).Advantages of the 2.5" format:
- Prevalence on the market, any volume available
- Convenient and easy to use, compatible with any motherboard
- Reasonable price
- Relatively low speed among ssds - up to a maximum of 600 MB/s per channel, versus, for example, 1 Gb/s for the PCIe interface
- AHCI controllers that were designed for classic hard drives
mSATA SSD
There is a more compact form factor - mSATA, sizes 30x51x4 mm. It makes sense to use it in laptops and any other compact devices where installing a regular 2.5” drive is impractical. If they have a connector, of course. mSATA. In terms of speed, this is still the same specification SATA3(6 Gbps), and is no different from 2.5".
M.2 SSD
There is another, most compact form factor M.2, gradually replacing mSATA. Designed mainly for laptops. Dimensions - 3.5x22x42(60.80) mm. There are three different lengths of strips - 42, 60 and 80 mm, please pay attention to compatibility when installing in your system. Modern motherboards offer at least one U.2 slot for the M.2 format.M.2 can be either a SATA or PCIe interface. The difference between these interface options is in speed, and quite large at that - SATA drives boast an average speed of 550 MB/s, while PCIe, depending on the generation, can offer 500 MB/s per lane for PCI-E 2.0. and speeds up to 985 Mb/s per PCI-E 3.0 line. Thus, an SSD installed in a PCIe x4 slot (with four lanes) can exchange data at speeds of up to 2 Gb/s in the case of PCI Express 2.0 and up to almost 4 Gb/s when using PCI Express third generation.
The differences in price are significant; an M.2 form factor drive with a PCIe interface will cost on average twice as much as a SATA interface with the same capacity.
The form factor has a U.2 connector, which may have connectors that differ from each other keys– special “cutouts” in them. There are clues B and and also B&M. Differ in bus speed PCIe: key M will provide speed up to PCIe x4, key M speed up to PCIe x2, like a combined key B&M.
B- the connector is incompatible with M- connector, M-connector, respectively, with B- connector, and B&M The connector is compatible with any. Be careful when purchasing format M.2, since the motherboard, laptop or tablet must have a suitable connector.
PCI-E SSD
Finally, the last existing form factor is as an expansion board PCI-E. Mounted in the slot accordingly PCI-E, have the highest speed, order 2000 MB/s read and 1000 MB/s write. Such speeds will cost you a lot: obviously, you should choose such a drive for professional tasks. 
NVM Express
There are also SSD having a new logical interface NVM Express, designed specifically for SSDs. It differs from the old AHCI in even lower access latencies and high parallelism of memory chips due to a new set of hardware algorithms.There are models on the market with a connector M.2, and in PCIe. The only downside of PCIe here is that it will take up an important slot, which may be useful for another board.
Since the standard NVMe designed specifically for flash memory, it takes into account its features, while AHCI still just a compromise. That's why, NVMe is the future of SSDs, and will only get better and better over time.
What type of SSD memory is better?
Let's understand memory types SSD. This is one of the main characteristics SSD, determining the cell rewriting resource and speed.MLC (Multi-Level Cell)- the most popular type of memory. Cells contain 2 bits, as opposed to 1 bit in the old type SLC , which is almost no longer on sale. Thanks to this, there is a larger volume, which means lower cost. Recording resource from 2000 to 5000 rewrite cycles. In this case, “overwriting” means overwriting each cell of the disk. Therefore, for a 240 GB model, for example, you can record at least 480 TB of information. So, such a resource SSD even with constant intensive use, about 5-10 years should be enough (during which time it will still become very outdated). And for home use, it will last for 20 years, so the limited rewrite cycles can be ignored altogether. MLC– this is the best combination of reliability/price.
TLC (Triple-Level Cell)- from the name it follows that here 3 bits of data are stored in one cell at once. Recording density here compared to MLC higher by whole 50% , which means the rewriting resource is less - only 1000 cycles. The access speed is also lower due to the higher density. The cost now is not much different from MLC. It has been widely used in flash drives for a long time. The service life is also sufficient for a home solution, but the susceptibility to uncorrectable errors and “dying out” of memory cells is noticeably higher, and during the entire service life.
3D NAND- This is rather a form of memory organization, and not its new type. There is both MLC, so TLC 3D NAND. Such memory has vertically arranged memory cells, and an individual memory crystal in it has several levels of cells. It turns out that the cell has a third spatial coordinate, hence the prefix "3D" in the memory name - 3D NAND. It is distinguished by a very low number of errors and high endurance due to a larger technical process of 30-40 nM.
The manufacturer's warranty for some models reaches 10 years of use, but the cost is high. The most reliable type of memory available.
Differences between cheap SSDs and expensive ones
Disks of the same capacity, even from the same manufacturer, can vary greatly in price. A cheap SSD may differ from an expensive one in the following ways:· Cheaper type of memory. In ascending order of cost/reliability, roughly: TLC≥ MLC ≥ 3D NAND.
· Cheaper controller. Also affects read/write speed.
· Clipboard. The cheapest SSD may not have a clipboard at all, this does not make them much cheaper, but it noticeably reduces performance.
· Protection systems. For example, expensive models have protection against power interruption in the form of backup capacitors, which allow the write operation to be completed correctly and not lose data.
· Brand. Of course, a more popular brand will be more expensive, which does not always mean technical superiority.
Conclusion. What is more profitable to buy?
It is safe to say that modern SSD The drives are quite reliable. The fear of data loss and the negative attitude towards solid-state drives as a class are completely unjustified at the moment. If we talk about more or less popular brands, then even cheap TLC The memory is suitable for budget home use, and its resource will last you for at least several years. Many manufacturers also provide a 3-year warranty.So, if you are limited in funds, then your choice is a capacity of 60-128 GB to install the system and frequently used applications. The type of memory is not so critical for home use - TLC will it be or MLC, the disk will become obsolete before the resource is exhausted. All other things being equal, of course, it is worth choosing MLC.
If you are ready to look into the mid-price segment and value reliability, then it is better to consider SSD MLC 200-500 GB. For older models you will have to pay about 12 thousand rubles. At the same time, the volume is enough for you for almost everything that needs to work quickly on your home PC. You can also take models of even higher reliability with memory crystals 3D NAND .
If your fear of flash memory wearing out reaches panic levels, then it's worth looking at new (and expensive) technologies in the form of storage formats 3D NAND. All jokes aside, this is the future. SSD– high speed and high reliability are combined here. Such a drive is suitable even for important server databases, since the recording resource here reaches petabyte, and the number of errors is minimal.
I would like to include drives with an interface into a separate group PCI-E. It has high read and write speed ( 1000-2000 Mb/s), and on average more expensive than other categories. If you prioritize performance, then this is the best choice. The disadvantage is that it takes up a universal PCIe slot; motherboards of compact formats may only have one PCIe slot.
Beyond competition - SSD with NVMe logical interface, the reading speed of which exceeds 2000 MB/s. Compared to compromise logic for SSD AHCI, has much greater queue depth and concurrency. High price in the market, and the best characteristics - the choice of enthusiasts or professionals.
Any electronic computer includes memory storage devices. Without them, the operator would not be able to save the result of his work or copy it to another medium.
Punch cards
At the dawn of their appearance, punched cards were used - ordinary cardboard cards with digital markings applied.
One punched card contained 80 columns, each column could store 1 bit of information. The holes in these columns corresponded to a unit. The data was read sequentially. It was impossible to re-write anything onto a punched card, so a huge number of them were required. To store a 1 GB data array would require 22 tons of paper.
A similar principle was used in punched paper tapes. They were wound onto a reel, took up less space, but often tore and did not allow adding or editing data.
Floppy disks
The advent of floppy disks was a real breakthrough in information technology. Compact, capacious, they allowed storage from 300 KB on the earliest samples to 1.44 MB on the latest versions. Reading and writing were carried out on a magnetic disk enclosed in a plastic case.
The main disadvantage of floppy disks was the fragility of the information stored on them. They were vulnerable to damage and could become demagnetized even in public transport - a trolleybus or tram, so they tried not to use them for long-term data storage. Floppy disks were read in disk drives. At first there were 5-inch floppy disks, then they were replaced by more convenient 3-inch ones.
Flash drives have become the main competitor to floppy disks. Their only drawback was the price, but as microelectronics developed, the cost of flash drives dropped dramatically and floppy disks became history. Their production finally ceased in 2011.
Streamers
Streamers were previously used to store archived data. They were similar to video cassettes in appearance and operating principle. Magnetic tape and two reels made it possible to sequentially read and write information. The capacity of these devices was up to 100 MB. Such drives have not received mass distribution. Ordinary users preferred to store their data on hard drives, and it was more convenient to store music, films, and programs on CDs and later DVDs.
CD and DVD
These information storage devices are still in use today. An active, reflective and protective layer is applied to the plastic substrate. Information from the disk is read by a laser beam. A standard disk has a capacity of 700 MB. This is enough, for example, to record a 2-hour movie in average quality. There are also double-sided discs, where the active layer is sprayed onto both sides of the disc. Mini-CDs are used to store small amounts of information. Drivers and instructions for computer products are now written specifically for them.
DVDs replaced CDs in 1996. They made it possible to store information with a volume of 4.7 GB. They also had the advantage that the DVD drive could read both CDs and DVDs. At the moment this is the most popular memory storage device.
Flash drives
The CD and DVD drives discussed above have a number of advantages - low cost, reliability, the ability to store large amounts of information, but they are designed for one-time recording. You cannot make changes to the recorded disc, add or remove unnecessary things. And here a fundamentally different storage device comes to our aid - flash memory.
He competed with floppy disks for a while, but quickly won the race. The main limiting factor remained the price, but now it has been reduced to an acceptable level. Modern computers are no longer equipped with disk drives, so a flash drive has become an indispensable companion for everyone who deals with computer equipment. The maximum amount of information that fits on a flash drive reaches 1 Tb.
Memory cards
Phones, cameras, e-books, photo frames and much more require memory storage devices to operate. Due to their relatively large size, USB flash drives are not suitable for this purpose. Memory cards are specially designed for such cases. Essentially, this is the same flash drive, but adapted for small-sized products. Most of the time, the memory card is located in an electronic device and is removed only to transfer accumulated data to permanent media.
There are many memory card standards, the smallest of which measure 14 by 12 mm. On modern computers, instead of a disk drive, a card reader is usually installed, which allows you to read most types of memory cards.
Hard drives (HDD)
Memory drives for a computer are inside it there are metal plates coated on both sides with a magnetic composition. The engine rotates them at a speed of 5400 for older models or 7200 rpm for modern devices. The magnetic head moves from the center of the disk to its edge and allows you to read and write information. The capacity of a hard drive depends on the number of disks in it. Modern models allow you to store up to 8 TB of information.
There are practically no disadvantages to this type of memory drive - these are very reliable and durable products. The cost per unit of memory in hard drives is the cheapest among all types of drives.
Solid State Drives (SSD)
No matter how good hard drives are, they have almost reached their ceiling. Their performance depends on the rotation speed of the disks, and its further increase leads to physical deformation. Flash technology, which is used in the manufacture of solid-state memory drives, does not have these disadvantages. They do not contain moving parts, therefore they are not subject to physical wear, are not afraid of impacts and do not make noise.
But there are still serious shortcomings. First of all - the price. The cost of a solid-state drive is 5 times higher than a hard drive of the same size. Another significant drawback is the short service life. Solid state drives are usually chosen for installing the operating system, and a hard drive is used for data storage. The cost of solid-state drives is steadily decreasing, and there is progress in increasing their service life. In the near future, they should supplant traditional hard drives, just as flash drives supplanted floppy disks in their time.
External drives
Internal storage and internal memory are good for everyone, but you often need to transfer information from one computer to another. Back in 1995, the USB interface was developed, allowing you to connect a wide variety of devices to a PC, and memory drives were no exception. At first these were flash drives, later DVD players with a USB connector appeared and, finally, HDDs and SSDs.
The attractiveness of the USB interface is its simplicity - just plug in a flash drive or other storage device and you can work, no driver installation or other additional steps are required. The development of the interface and the appearance first of USB 2.0 and then of USB 3.0 sharply increased the speed of data exchange over this channel. The performance now differs little from the internal one, and their size cannot but rejoice. An external memory drive fits easily in the palm of your hand and allows you to store hundreds of gigabytes of information.
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An SSD drive is already becoming a mandatory attribute not only for laptops and netbooks, but also for desktop computers.
In this article I will try to understand what an SSD drive is and describe its strengths and weaknesses. We will also consider its use in home computers.
What you will learn by reading this article:
What is an SSD disk?
An SSD is a solid-state drive that uses flash memory (NAND) to store data. The abbreviation SSD can be deciphered as Solid State Disk or Solid State Drive, but the second option seems more correct to me.
An SSD drive has no mechanical or moving parts, which makes it more reliable than a mechanical HDD.
The first prototypes of modern solid-state drives were produced on the basis of RAM memory, and in order not to lose information after turning off the computer, a battery was connected to it.
Now, of course, SSD drives are made using a different technology and turning off the computer will not lead to loss of information.
What does an SSD disk consist of?
The main parts that make up an SSD are a flash memory chip, a controller, a disk connection interface, and a housing.
Flash memory chip.
Currently, modern SSDs use three types of memory: SLC, MLC and TLC.
SLC (Single-Level Cell) - one bit of information is written to each cell of this memory. The number of rewrite cycles is 100,000. It has the largest rewrite margin, but it is also the most expensive memory and is used in expensive server systems.
MLC (Multi-Level Cell) – two bits of information are written to each cell. The number of rewrite cycles is 3000. This memory is used for the production of most SSD drives, as it is less expensive and has the potential for large amounts of disk space.
TLC (Triple-Level Cell) – three bits of information are written to each cell. The number of rewrite cycles is 1000. The cheapest type of memory has long been used in the production of flash drives. It is also starting to be used in the production of SSD drives, which makes their production even cheaper, for example, Samsung 840 EVO.
The number of rewrite cycles can vary upward, it depends on the production technology, and it does not stand still.
When memory cells wear out, they become blocked, so the disk itself remains functional, it only loses capacity. But if you use it correctly, and take into account its size, then the service life of an SSD will be several years.
The main manufacturers of memory chips are Intel, Hynix, Micron, Samsung, SanDisk and Toshiba.
If we talk about the memory sizes of SSD disks, then at the moment you can find disks with a capacity of 1TB. But the price of such a disk is still too high, for example, an 800GB disk with a SATA3 interface costs about 80,000 rubles, and with a PCI-E interface, about 160,000 rubles. Not everyone wants to buy themselves a fast flash drive for that amount.
Controller.
The controller is the processor that manages read and write operations. This is the second most important element in a solid-state drive, after memory.
The controller's duties include:
Constant monitoring of the state of memory cells and blocking them when completely worn out;
Uniform distribution of files throughout the disk for uniform wear of memory cells;
Transferring data from memory to RAM memory, if available;
Compress files to speed up transfer;
The speed of reading and writing depends not only on the memory, but also on the controller. So, for example, in cheap disks, the speed of the controller may be limited if there is fast memory; as a result, the read and write speed of the disk will be lower.
SSD form factor.
SSD drives are available in different formats. There are currently five of them in total.
SATA – This is the most common type of 2.5-inch drives. They can be installed on both a desktop PC and a laptop. Only in a laptop you will have to remove a larger HDD or CD-ROM. 1.8-inch drives with a SATA interface are less common. I advise you to take SATA-3 format drives, their read/write speed is much higher than SATA-2, about 500MB/s and higher.
mSATA – As a rule, disks of this format are installed in laptops, where a special compartment is designed for them. In terms of speed, some models are inferior to SATA drives.
PCI-E – The highest read/write speed, thanks to the PCI-E bus, is shown by disks of this particular format, up to 2000 MB/s. But they are also the most expensive of the solid-state ones.
Hybrid (SSHD) – These are disks where a regular hard drive is used as the main storage device, and an SSD drive is used as cache memory. This method allows you to quickly launch applications that you use frequently. In general, the speed of such a disk is the same as that of a regular HDD, but some programs run very quickly.
USB – External drives are not very fast because the USB port is the weak link. I advise you to buy drives with a USB 3.0 interface, as the speed will be much higher than USB 2.0. But the external drive never required the same speed as the internal one. So, if speed is not so important to you, then it is better to buy a regular hard drive, which is cheaper and has more capacity.
Advantages of SSD drives.
Fast file access – SSDs have no moving head or disk and read them almost instantly.
High data transfer speed – For the same reason, SSD has a very high data transfer speed.
Good shock resistance – Again, there are no fragile mechanisms and nothing to break under light impacts.
Less power consumption – There are no drives or moving parts, and much less energy is required to operate solid state devices.
Low noise level – Same story here, nothing moves or makes noise.
Disadvantages of SSD drives.
High cost of solid state drives.
Less disk space compared to HDD.
Limited data rewrite cycle.
Of course, all these shortcomings are a temporary phenomenon and soon solid-state ones will catch up and surpass mechanical ones, and they, in turn, will become hopelessly outdated.
Now, of course, you can use an SSD drive in a personal computer, but only as the main one where the system is installed, and not as storage for your files.
I will tell you how to extend the life of a solid-state drive in one of the following articles. If you have not yet subscribed to updates, you can do so now.
If you are going to buy a computer and don’t know how to choose a processor, then I recommend reading this, which describes the main criteria for choosing a processor for a computer.
Good luck!
Register, adder, storage device, memory, storage device, accumulator, money-grubber, storage device, hard drive, disk, storage device Dictionary of Russian synonyms. accumulator noun, number of synonyms: 21 nitrogen accumulator... Synonym dictionary
storage device- A device for creating a certain supply of processed metal in the line of a continuous technological unit, ensuring the continuity of its operation, for example, a roll storage unit in the line of a continuous annealing unit (CAN) of a strip.… … Technical Translator's Guide
STORAGE, me, husband. 1. A person who hoards is engaged in hoarding. 2. A device, a container for collecting, accumulating, storing something. (specialist.). Storage ponds (for water drainage). Bunker. Telezhkan. | wives accumulator, s (to 1 value). |… … Ozhegov's Explanatory Dictionary
Charged particles (storage ring), an element of a system of colliding beams, which is an annular vacuum chamber located in a magnet. field, in which particles from a large number of charging acceleration cycles accumulate and circulate for a long time. h... ... Physical encyclopedia
Storage device- a device for creating a certain supply of processed metal in the line of a continuous technological unit, ensuring the continuity of its operation, for example, a roll storage device in the line of the unit... ... Encyclopedic Dictionary of Metallurgy
STORAGE DEVICE- a device for creating a certain supply of processed metal in the line of a continuous technological unit, ensuring the continuity of its operation, for example, a roll storage device in the line of the unit... ... Metallurgical dictionary
storage device- Memory device; memory; industry storage device; drive Part of a computer designed for recording, storing and issuing information presented in code form. Device for accumulating and retaining accelerated... ... Polytechnic terminological explanatory dictionary
storage device- kaupiklis statusas T sritis automatika atitikmenys: engl. accumulator; storage unit; store vok. Akkumulator, m; Speicher, m rus. battery, m; storage, m pranc. accumulateur, m; dispositif d emmagasinage, m … Automatikos terminų žodynas
I m. One who is engaged in accumulating something (property, money, etc.). II m. 1. A mechanism, a technical device, the main function of which is the accumulation of something. 2. Device for long-term storage of information; external memory... ... Modern explanatory dictionary of the Russian language by Efremova
1. drive, drives, drive, drives, drive, drives, drive, drives, drive, drives, drive, drives 2. drive, drives, drive, drives, drive, drives, drive,... ... Forms of words
Probably every person who is familiar with computer technology knows or has at least heard of such a device as an SSD drive. What is it and what role does it play in the operation of a computer? In short, SSD is used to record and store the user's personal data. You could argue that that's what hard drives are for. And this statement will be absolutely correct, because these components of the computer perform identical functions. So why was the SSD invented, what is it, how does it work and how does it differ from a regular HDD? All these questions can be answered in this article.
What is the difference between a hard drive and an SSD hard drive? What kind of device is this and what are the main principles of its operation?
Today, the main place to store most files on a computer is the hard drive. If you take it apart, you will find a rather fragile mechanism inside. It consists of magnetic plates rotating on a special head. A carriage moves between these plates, which finds and reads the necessary information. The hard drive mechanism resembles a gramophone, but these devices perform different functions. Unlike the mechanism of a musical device, the hard drive carriage moves at a speed of several thousand revolutions per minute and performs work related to copying and recording information.
As for the SSD disk, or, as it is commonly called, a solid state drive, it is used for the same purposes as a hard disk. It just works completely differently. There are no moving elements inside this device, but special chips are installed to store information. A solid-state drive resembles a large flash drive that can be placed in place of a hard drive.
Basic principles of operation of solid-state drives
The memory of SSD disks consists of special blocks that are divided into cells where the necessary data is stored. Everything would be fine, but the main problem arises when you need to delete or re-record existing information. The fact is that it is impossible to delete part of the information from one block, but you have to format the entire sector. In this case, the necessary data is stored in the cells of neighboring blocks and only then overwritten in the old place. Suppose you need to save data of 10 KB in size. In this case, the memory block has a volume of 20 KB, 10 KB of which are already occupied. In this case, the information available on the disk is transferred to another location, the entire block is deleted, and only then the old and new data are written down. It turns out that to carry out one operation, the system performs several additional actions, which leads to slower operation and accelerates the wear of the solid-state drive.
To increase the performance of the device, it is necessary to use a special program called TRIM, or, as it is sometimes called, SSD trimming. What it 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 the SSD to indicate unused elements. Thanks to this function, you can immediately delete unnecessary files, avoiding additional operations with transferring information to adjacent blocks. And this significantly improves SSD performance. But this command is not supported by older versions of operating systems. Therefore, to connect TRIM, Windows 7 or 8, Linux version 2.66.33 or higher must be installed on the computer.
What does an SSD consist of?
Having studied the differences between the two types of information storage, we will dwell in more detail on how SSD solid-state drives are designed, what kind of devices they are and how they function. In appearance, this is an ordinary box with connectors for connecting to a computer. Basically, SSD drives for home use are equipped with Sata, USB 3.0 and PCI-Express interfaces, which easily provide the required writing and reading speeds.
SSDs do not have any moving mechanical parts. Thanks to this, they are much more resistant to external factors. For example, an ordinary HDD disk is a rather fragile thing, because if during shaking or falling the read head comes into contact with the magnetic plate, this will lead to the failure of the media. But solid-state drives are designed completely differently. Inside these devices, special boards are installed on which memory chips and a controller are soldered. Some SSD drives are additionally equipped with compact batteries, which in the event of a sudden power outage provide the cache with additional power, and the data is saved to the main memory chips. Now let's take a closer look at the main components of a solid-state drive.
SSD memory: what is it and what are its main functions?
Most SSD drives use NAND, or, as it is also called, flash memory. Similar chips are used in regular flash drives, only in solid-state drives they are more reliable and have greater speed due to the presence of a controller. Due to their low cost, they are widely used in SSDs, making these devices quite affordable for most users. Another advantage of this is that it is non-volatile and will not require additional power to operate.
In addition to NAND technology, solid-state drives sometimes use RAM-SSD. This type of memory has a high speed of writing and reading data due to the use of chips used to create RAM. It will require a constant connection to electricity, so SSD drives that use RAM often have additional batteries installed in case of a sudden power outage. Due to the high cost of producing these drives, they are rarely found in home PCs and laptops. RAM-SSDs are mainly used in computer systems of large companies to increase the speed of working with databases.
Today, most drives use NAND memory. Despite this, these SSD drives differ from each other in speed of writing, reading data and cost. It all depends on the chips used in the drive: SLC, TLC or SSD MLC. What is it and what is the difference between them? This is how different ones are designated. 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 wear, so this technology is not very popular. The fastest and most durable is SLC memory, with which you can write only one bit of data in each cell. Among the disadvantages, we can only highlight the high cost, which is 2 times higher than the price of an MLC SSD.
Controller
The controller is the most important element, without which the SSD cannot function. What it is and what its role is, we will find out further. These devices perform the work of distributing the load between memory blocks, are responsible for reading and writing information, error correction and file compression. The controller resembles a command center where decisions related to data processing are made. The speed of operation of the solid-state drive and its durability depend on this detail. The main component of the controllers is a special microprocessor, which bears the entire load. Also, the performance of the device depends on the quality of the firmware.
Quite a lot of companies are engaged in the production of SSD drives, because the technology for their production is quite simple and requires less time than creating a classic hard drive. All you need is to purchase memory chips, controllers and boards where everything will be soldered. After this, the design is placed in a beautiful case with a company logo - and the product is ready for sale. But the components themselves for solid-state drives have a high price, and the creation of a controller and high-quality firmware for it will require large expenses. Because of this, the cost of SSD drives today is much higher than conventional HDDs.
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 more and more popularity. Technology does not stand still, and standard hard drives are gradually replacing more technologically advanced systems. SDD drives are present in many computers, but are used not as the main storage of information, but as an additional one. And all because their cost is significantly higher compared to conventional hard drives. To compensate for this gap between the two types of drives, a hybrid HDD SSD was created. Let’s try to consider in more detail what kind of device this is and what advantages it has.
The hybrid drive is based on the same HDD without any changes. But chips with flash memory are also installed in the body of these drives, which are used as a buffer zone. The information that is most frequently used is copied to it. This made it possible to increase the loading speed of some applications and the operating system itself when compared with conventional hard drives. The maximum amount of flash memory in such hybrid SSDs is 8GB. What was the result? In fact, we have something between a hard drive and a small solid-state drive. You cannot load data or install applications into buffer memory. It is used as a reserve for running priority programs that the user cannot control independently. As for the price, the cost of hybrid drives is lower than standard SSDs, but higher than HDDs; moreover, they are not very popular in our country, so they are not sold everywhere.
Benefits of a Solid State Drive
An integral part of a modern computer is an SSD drive. We have found out what kind of device this is and how it works, all that remains is to highlight its main pros and cons compared to conventional HDDs. Let's start with the positive aspects of SSDs.
The most important advantage of an SSD is its incredible storage of information. They are several times more productive than hard drives. For example, the data processing speed of some drives exceeds 500 MB/s. In practice, this results in faster operation of programs and the operating system itself, which loads in a matter of seconds. This is very important, because the current generation of computers has high performance, which is greatly slowed down by HDDs. But with the advent of new drives, their speed has increased significantly.
Another advantage of SSD devices is their higher resistance to external factors. They do not have such a fragile mechanism as hard drives. Thanks to this, they can easily withstand shaking, vibration and moderate impacts to the body. These devices will be an excellent solution for laptops. In addition, they cope better with temperature changes.
Another advantage of SSD is its quietness and low power consumption. Because hard drives have moving mechanical parts, they produce a certain level of noise. In addition, in operating condition, HDDs have a fairly high temperature, so the coolers have to rotate at an accelerated rate. But all these problems are absent from SSDs, which do not heat up, do not make noise and consume less electricity.
Flaws
Having assessed 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 them is the high cost of such drives. Despite the simplicity of their design, manufacturing flash memory chips and controllers is quite an expensive business. But there is no need to be upset about this, because technology is constantly developing, and the price of these goods is gradually decreasing. In a couple of years, they may well be equal in price to HDDs.
After the first drawback, a second one can be identified. Due to their high cost, SSDs have lower storage capacity than HDDs. For example, the memory capacity of some HDDs is 8 TB, while SDDs only reach 1 TB.
SSD memory is short-lived and will fail after a certain number of write cycles. Although the current generation of these devices has a fairly long service life, you must be prepared for the fact that one day the drive will stop working, and it will be problematic to restore information.
I would like to add that SSDs do not tolerate power surges quite well. If after one of these voltage drops it burns out, then it will be impossible to obtain data. In the case of an HDD disk, a certain sector in it will fail, but most of it will remain intact, thanks to which all undamaged information can be retrieved.
What should you pay attention to when buying an SSD?
Having studied the information about solid-state drives, many users probably wanted to purchase this device for their computer. But you don’t have to immediately run to the store and grab the first product that comes your way. Here are some tips to help you choose an SSD.
First you need to pay attention to the size of the SSD. What it is? In other words, this is the amount of built-in. The higher its value, the more information can be recorded. But you don’t need to buy the most expensive products, because solid-state drives are mainly used for installing operating systems and applications on them, and the main storage location is still the hard drive. By equipping your system with an SSD of only 60-120 GB, you can achieve a significant increase in the performance of your computer.
Reading and copying speed plays an important role. The higher it is, the better, but it happens that the motherboard cannot reveal the full potential of the SSD drive due to the low bus bandwidth. It happens that there is no point in installing fast drives in old laptops or PCs at all, because even after the update the system will work the same as on a regular HDD. Therefore, it is worth studying the configuration of your computer, and only then going to the store. The largest ones are, and for outdated IDE ports you will need a special adapter to install an SSD.
The most important component of any SSD is the controller. It is this detail that controls all processes associated with information processing. The durability of the entire device depends on how well it is made, so it is recommended to give preference to proven and proven manufacturers. The leaders in production are SandForce, Marvell, Intel, Indilinx.
Finally, you should pay attention to the dimensions of the drive. For a PC, this is not so important, because any SSD can be installed in the system unit, but problems may arise with laptops.
Basic rules for using solid-state drives
After looking at reviews from users and experts, we can conclude that an SSD hard drive is an integral part of a modern computer. We have already looked at what it is and how it works. Now you need to learn how to use it correctly. As strange as it may sound, in order to understand all the advantages of solid-state drives, you need to follow a few simple rules.
There is no need to fill all available memory to capacity. Many people neglect this rule, because SSDs are quite expensive, so users buy small drives and completely load them with necessary and not so necessary information. But we must remember that if you leave less than 25% of free space, the data processing speed will decrease significantly. The fact is that the more memory, the higher the number of free blocks where data can be written. When there is too little space left, information is distributed across the cells of neighboring blocks, and this leads to a decrease in performance.
It is worth remembering that using solid-state drives you can significantly increase the performance of your computer, so it is recommended to install the operating system, applications and demanding games on them. But you should use HDD as the main information storage. This will be more economical and practical, because they can easily cope with playing audio and video files no worse than SSDs.
It is best to have one of the latest versions of operating systems installed on your computer. For example, Windows XP or Vista are poorly optimized for working with solid-state drives and do not support the TRIM command.
