design and operation of solid state hard drives

By | 10.12.2018



The structure and operation for solid state drives

Solid state hard drives for computer gadgets that can store various data and to carry out the processing with a very high speed. The secret of high performance lies in a fundamentally different device this gadget. There are no rotating pancakes, over which hovers a writing head as in mechanical analogues. This is the main reason for the great performance.

Despite the fact that the disks of this type have both advantages and disadvantages, they are often installed in laptops and other computers with their outdated counterparts. But it’s rare that you come across PC models that use the disks, just the old type.

What it is

The SSD is a special, non-mechanical storage device that is hosting all the information in memory chips, placed on a special Board. In addition, the design of the device in question also has a large number of other component parts.

There are two main types of drives of this kind:

  • NAND;

    Устройство и работа твердотельных жестких дисков

  • DRAM.

    Устройство и работа твердотельных жестких дисков

As indicated by a variety of circuits used for storing and processing data. The major differences between them, but DRAM drives are equipped with built-in battery. Can sometimes be found in the sale of SSHD – hybrid devices. In one case are ordinary disks, and memory chips. The operation of read and write faster than HDD, but slower than a normal SSD.

The disk device

This component of a personal computer consists of the following parts:

  • rewritable memory chip;
  • Trustee of the microcontroller;
  • chip volatile memory;
  • the printed circuit Board.

    Устройство и работа твердотельных жестких дисков

The most important parts are the controller and flash memory. They are the main reason for the large performance increase with this device.

The controller

The controller itself contains:

  • microprocessor;
  • a bridge for transmitting signals.

    Устройство и работа твердотельных жестких дисков

The SSD controller performs the following functions:

  • read, write, cache;
  • data encryption;
  • monitoring (S. M. A. R. T.);
  • data compression (some models of controllers).

Flash memory

Most often in these gadgets is a chip type NAND. She is volatile and has a relatively low cost compared to its counterparts and allows you to save data even in the absence of a constant supply of power.

NAND can be of different types:

  • MLC;

    Устройство и работа твердотельных жестких дисков

  • SLC.

    Устройство и работа твердотельных жестких дисков

MLC-type contains one cell more than one bit of data. But at the same time, schemes of this kind have some disadvantages such as low resource, and low speed of reading and writing. When using SLC-type in one cell is written to a single bit. This provides greater durability and processing speed. The disadvantage is the price – it in 2 times higher than the cost of MLC.

How it works

The operation of the conventional HDD is extremely simple, read and write information in it can be carried out simultaneously. The SSD works on a different principle. This provides a significant performance boost. In memory circuits under consideration gadget all operations are performed in a sectoral way. Recording is done in blocks of 4 KB, and the deletion of data blocks of 512 KB.

Устройство и работа твердотельных жестких дисков

In the implementation of the information processing performs the following operations:

  • the reading of the memory block;
  • all requested bytes are subject to modification;
  • is the Erasure of the processed block in the memory circuit;
  • the algorithm movement is calculated another location of the unit;
  • the block is rewritten in a new sector.

Video: the Settings for HDD and SSD

The reliability of the drives

It is believed that SSDS are much more reliable than HDD. And there are serious reasons. The lifetime of the SSD depends on many factors.

The most important:

  • the total number of the rewritable information;
  • the number of overwriting the entire memory.

It is from these two factors depends how long will last the gadget to its user. But the most important advantage compared to conventional HDD – immunity to mechanical stress. SSD can move, shake and drop even in the process of reading and writing data. This does not harm the information on it. For conventional HDD such actions are unacceptable.

Устройство и работа твердотельных жестких дисков

Also considering the gadget has a greater resistance to various kinds of electro-magnetic fields and similar influences. The likelihood of circuit damage due to a nearby strong magnet, or object with similar properties practical completely eliminated. That is especially important for tablets, laptops and other devices that are moved together with its owner.

Security

One of the most important advantages of SSD is data storage security. It is related to a method of recording – it performs the electrical method, which allows for a more complete Erasure of previously recorded information. In addition to the standard method can also be used specialized software carries out a full removal.

Устройство и работа твердотельных жестких дисков

Recording to HDD is performed by mechanical means. Accordingly, always remain all sorts of traces. Which leads to the possibility of data theft or recover them after deletion. Almost all the controllers, SSD, and SSHD to date are supplied with a special protection that allows you to encrypt the recorded data. Therefore, to restore the removed information difficult.

Optimization

The gadget of this type operates extremely fast without any additional optimization tools. Perhaps this is due to the absence of the need to move the special block heads. This saves a lot of time. However, using certain steps, you can do the job even faster.

This can be done by disabling the following options:

  • indexing;
  • the paging file;
  • Prefetch and SuperFetch;
  • system restore.

To disable indexing of the data is enough to go into the properties of SSDS and in the appeared window clear the check box next to «allow indexing of files.»

Устройство и работа твердотельных жестких дисков

Then, you should close the window and continue working. Thus, it is possible to achieve productivity gains of 3-4%.

Pretty much to increase the speed of transfer allows or disabling the paging file.

Устройство и работа твердотельных жестких дисков

To do this, simply do the following:

  • open the control panel;
  • start the shortcut called administration;
  • select the service section.

Find the desired item and double click on it. Put the dot next to «no paging file».

Устройство и работа твердотельных жестких дисков

To disable Prefetch, you must find the key HKEY_LOCAL_MACHINESYSTEMCurrentControlsetcontrolsessionmanagermemory ManagementPrefetchParameters. After that you should change the value of parameters EnablerPrefetcherи EnableSuperfetch to 0.

To disable SuperFetch required to find the key HKEY_LOCAL_MACHINESYSTEMCurrentControlsetcontrolsessionmanagermemory Management. There are options ClearPageFileAtShutdown and LargeSystemCache, you should change the value to 0.

If all the above steps, you can speed up the operation of a personal computer by as much as 15-20%. This is a positive impact on the work of both the operating system and various programs that require constant access to the drive.

Video: statistics of reliability of the HDD

Advantages and disadvantages

Drives of this type have both advantages and disadvantages.

The advantages include the following features:

  • high processing speed (all current models – more than 200 MB/s);
  • low power consumption (less than 1 watt compared to HDDs of the same capacity);
  • the almost complete lack of heating at work;
  • complete silence during operation.

Testing conducted by Intel showed that in the process, the laptops equipped with SSDs are heated at 12.20 With less than the same model equipped with a conventional HDD. Drives of this type have significantly lower weight, which is especially important for portable devices.

Устройство и работа твердотельных жестких дисков

There are also various disadvantages:

  • relatively high cost;
  • a limited number of write cycles;
  • you cannot restore deleted content.

The cost of an SSD is its biggest drawback. Price per 1 GB of data on average several times higher than the price for the same HDD. But every day the cost for these gadgets drops, which is why SSDS are used more often.

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Cells used memory have a limited resource. That is why it is extremely important to treat the swap file and various applications, often referring to ROM. Although gadgets sold today, the resource is large enough, you must use special software to constantly monitor status.

Impossibility of data recovery is both and advantage and a disadvantage. Since this feature allows you to minimize the likelihood of theft of the information. But at the same time, there is no possibility of recovery as a result of erroneous deletion.

Review of prices by producers

The name of the manufacturer

Size, GB

Model name

Cost, RUB.

A-Data

64

Premier Pro SP600

2 790

AMD Radeon

120

R7 Series

5 990

Asus

240

RAIDER Express

19 990

Corsair

60

LS CSSD-F60GBLS

2 950

Crucial

128

M550

5 490

Intel

80

530 Series

5 450

Kingmax

60

SMP35 Client

2 690

Kingston

60

SV300S37A

2 950

Patriot

120

Patriot Pyro

4 690

The cost of the gadgets of this type from different manufacturers may vary significantly. But when you run surveys and an objective assessment of similar models from different brands it turns out that the margin is for the most part for the brand.

Today it becomes clear what drives this type of future, and a conventional HDD gradually fading. Every day SSD is becoming more popular, this is a consequence of its portability and high speed. An increasing number of different laptops, tablets, smartphones and ordinary personal computers are equipped with the equipment of this type.




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