SSD, what is it?

SSDSSD stands for Solid State Disk, used to refer to the new generation of storage devices for PCs though since they do not carry discs inside now it is more correct to use Solid State Drive, i.e. solid state drive. These contrary occurring with rigid hard drives uses a memory made up of semiconductors to store information, similar to that you can find in other devices such as digital cameras memory cards or USB skewers.
Rigid hard disks, because work with a number of dishes on which magnetic fields are used to enter information and reading heads, have several drawbacks:

Deferred read/write times. The discs rotate continuously and the heads move angularly. This implies that he is accessing the information at the same speed. The time depends on the remote that are heads data at the time you want to access them.

That may seem like a trivial problem, it is not. If a file is not stored in contiguous way in the disk, it will be necessary to make several jumps to get to read the information. By this the performance of conventional discs suffer much if not you occasionally perform defragmentation, which is not to sort data in each of the files.

Reliability. Operation makes these hard drives are vulnerable to movements. Even in older units had to Park, i.e. leave fixed, the heads if it was not going to use the hard drive to prevent these damage dishes.

This is no longer necessary, but still continue to have problems with shock and vibration.

The SSD come to solve many of these problems to not contain any moving parts inside.
How does a hard drive SSD?

They have two areas of memory, one in which all information is saved even if you lose your power and another, much smaller, which acts as a cache to accelerate access. This whole system is governed by a controller that acts to coordinate the different elements.

To improve the speed and resistance to bugs, we have several blocks of memory that act as a RAID in miniature.
What do I get by purchasing a hard disk SSD?

The advantages compared to a traditional hard drive are several:

Quickly. Both the search for data in subsequent readings. A unit of this type in the time you have to wait until the data flow is always the same. You don’t need to defragment.

Greater resistance. Having no moving parts they respond best to vibrations and shock.

Lower consumption. They need less power to operate. This makes them ideal for portable devices, also means that they wear out less heat and therefore increases its useful life.

Lower noise. Another advantage of having no moving parts.

It is possible to use hybrid configurations with a SSD hard drive that acts as a conventional hard drive cache. This is called SSD caching and can for example find it on motherboards with Intel chipset Z68.

There are other implementations in which the operating system decides if the files are located in the conventional hard disk or SSD. Thus not lost disk size as if it occurs in configurations hybrid.
Are these hard drives a problem?

Traditional hard disk technology has been using for decades, which has enabled to create very inexpensive devices. SSD disks appear as the solution to many problems but have the disadvantage that they are very expensive.

His only problem apart from its price is that hard drives SSD due to its mode of operation tend to be faster when they begin to use and they are losing speed with time. That was a serious problem in the first generations seems that already not so much.
Are they all the same SSD hard drives?

No, and furthermore given their variety can be classified in several ways.

According to your connection to your PC:

PCIe SSD. On a drive PCIe SSD unit is connected to a PCI Express port as if it were an additional internal card. This way they can operate much faster and not be limited by the SATA standard.

SATA SSD. It uses the same connector as a normal hard drive. This is your only option if you want to add a SSD to a notebook or laptop.

According to the technology used in its manufacture:

In any computer system information is stored as a string of ones and zeros. Each of these elements is what is called a bit of memory.

In the first SSD each occupied a cell, and each new generation tries to add more per cell, thus reducing the price needed to get to have the same capacity.

This has some side effects, these memories have a shorter life cycle because the electrical voltage levels in each cell are closer. According to this classification, we have the following models:

SLC. Acronym for Single Level Cell. It is the first one that I use. We have one bit per cell. We can now see them in Server due to its high price.

MLC. acronym for Multi Level Cell. We have two bits per cell. They can store four States.

TLC. Acronym for Triple Level Cell. We have three bits per cell. They can store eight States.