Solid State Disk

Solid state disk is composed of a control unit and a storage unit ( FLASH chip ), simply by solid state electronic memory chip array and made of hard disk, hard disk interface specification and the definition, function and method of use and the ordinary hard disk of the same, in product shape and size with ordinary hard consistency. The chip operating temperature range is very wide ( 40 ~ 85 ). Now widely used in military, automotive, industrial control, video monitoring, network monitoring, network terminal, electric power, medical, aviation, navigation equipment and other fields. Although the cost is higher, but is also gradually spread to the DIY market.

Due to the solid state hard disk technology and traditional hard disk technology is different, so produced many new memory manufacturer. Manufacturers only need to buy a NAND memory, coupled with appropriate control chip, can make the solid hard disk. A new generation of solid-state drive widespread adoption of SATA-2 interface and SATA-3 interface.

Solid state disk storage medium is divided into two kinds, one kind is the use of flash memory ( FLASH chip ) as a storage medium, another is the use of DRAM as a storage medium.

Based on the flash solid state disk

Based on the flash solid state disk: FLASH was used as a storage medium, which is what we usually say SSD. Its appearance can be made into a variety of appearance, for example: the notebook hard disk, hard disk, memory card, U micro disk style. The SSD solid-state hard drive is the biggest advantages can be moved, and the data protection from the power control, can adapt to various environments, but life is not high, suitable for individual users. The flash-based solid-state hard disk, the storage unit is divided into two categories:

SLC ( Single Layer Cell single unit ) and MLC ( Multi-Level Cell multilayer unit ). SLC is characterized by high cost, capacity is small, but fast, while MLC is characterized by a large capacity and low cost, but the speed is slow. Each unit is MLC 2bit, compared with SLC exactly doubled. However, because each MLC storage unit contains more information, the structure is relatively complex, the chance of error will increase, must conduct error correction, this action led to its performance significantly lagging behind the simple structure of the SLC flash memory. In addition, SLC flash memory has the advantages of high carbon number up to 100000 times, 10 times higher than the MLC flash memory. In addition, in order to ensure the life of MLC, the control chip check and intelligent wear balance algorithm, such that each memory cell write frequency can be assessed on average, reached 1000000 hours mean time between failures ( MTBF ).

Solid state hard disk based on DRAM

DRAM based solid state disk: DRAM is used as a storage medium, the application range is narrow. It follow traditional disk design, can be most of the operating system file system tools for volume setting and management, and provide the industry standard PCI and FC interface for connecting to a host or server. Application method can be divided into SSD disk and SSD hard disk array two. It is a kind of high performance memory, and the service life is long, a fly in the ointment is the need for independent power to protect data security.

Interface type

SSD hard disk interface type is divided into the mainstream:

SATA interface: SATA SATAII SATA3.0

PATA ( IDE interface: IDE44PIN IDE40PIN )

PCI-E interface: mSATA PCIE ( IDE ) PCIE ( SATA ) ZIF: ZIF interface