SSD is a flash – storage technology which will in the long-term replace the standard hard disk drive.

SSD stands for “Solid State Disk or also “Solid State Drive.”

The benefits of the SSD in comparison to the standard HDD are mainly: Mechanical robustness, very short data access time, lighter in weight, low energy consumption and therefore less heat loss, which mostly Notebooks benefit from which lengthens the battery life-time.

Current SSDs have easily outbid the spectrum of the widely used SATA-II- INTERFACE with 300 MB/s. Manufacturers  have dealt with this implementing a PCI-Express based RAID solution. Here many SSD components together with a RAID Controller are built on a PCI-E-x4 or 8x card enabling transfer rates of up to 1,4GB/s.  The trend is moving to SATA III. These reach a transfer rate of up to 550 MB/s.

Multi-Level-Cell (MLC) und Single-Level-Cell (SLC) are two different types of storage cells or generally speaking of NAND-Flash Storage.

SLC stores exactly one bit per cell. Costs more, however consumes less energy. Transfers data a little faster and all-in-all is more durable than MLC.

MLC stores more than one bit per cell. The main benefit is a higher storage density, since more than one bit per cell can be stored. So the double amount or even still larger amounts of information can be stored on the same chip surface as compared to single-level-storage. Especially with solid state memory this offers a significant price advantage in comparison to SLC, since the required chip surface is a very important cost factor in the manufacturing process.

The performance level of a SSD is dependent on the controller used. There are quite a few controller manufacturers. The most broadly used are from Intel, Jmicron, Indilinx, Samsung and Sandforce. In the mainstream-segment the most popular ones are the controller from Indilinx (“Barefoot” and  “Amigos”), in the high-end-segment products from Sandforce (“SF1200”, “SF1500”) are often used.

The more files that are deleted or rewritten the more time a standard SSD requires for the data storage process. The reason: What a magnetic hard drive accomplishes in 1 step, an SSD completes in 2 steps. If a file is deleted on an SSD through the operating system, then only the entry of this file in the directory is deleted, the actual file itself is still stored on several storage cells of the SSD. Over a period of time categories on the SSD are filled with data that has actually been deleted. When rewriting data, the SSD has to be emptied first before files can be rewritten which slows down the writing speed a little. The TRIM command prevents this from happening.

The bad block management of SSDs sees to it that data from flawed areas (cells) is pushed into functional cells. The defective cell is then excluded from the further storage of data and a new cell takes its place. Thus the storage capacity becomes smaller with the operating duration of the SSD, but the data security and the data transfer speed rates stay on the same level.

Uncorrectable bit error rates (UBER=Uncorrectable Bit Error Rates) occur when data read errors occur on an SSD. With  hard drives this value lies approx. by 1 error per 1016 bits read. The data transfer rate of an SSD lies vastly over 250 MB/s for the most part so the UBER must be quite high (over 1017) in order to ensure appropriate reliability.  SSDs therefore require a complex ECC-Protection. This means that an SSD controller must be flexible enough to process complicated ECC Algorithms.

Input and output operations per second are activity values for storage media. The dimension unit shows how many input and output demands an SSD and its controller can process. The higher this value is, the quicker and more storage capacity the SSD has.

The SuperCapacitor (Supercap) serves as a temporary but reliable energy buffer. In case of a sudden power loss the drive can complete its activity without losing the data. Supercap ensures weight savings and longer lifetime.

4KB builds the smallest standard block size which can be read or written in a file system. This is relevant especially for SSDs, since these work with 64KB sectors and not with 512 byte like magnetic drives. This means that an SSD must complete a higher workload than a hard drive.  With the help of the 4KB-random-write-benchmark the length of time a hard drive or SSD needs to register a block and insert this in MFT (Master File Table = Data System) is shown.

The garbage collection, in so far it is supported, is a firmware feature (Storage-Manager) which takes care of an automatic storage filtering/cleaning process. No longer needed data is already deleted from the storage cells before it is rewritten. This free storage area is available for future writing tasks. This filtering/cleaning minimises the demand of storage of a process. Inefficient use of the designated storage and a slowing down of the data transfer is avoided this way. In comparison to TRIM garbage collection is independent of the operating system and runs automatically.

Conventional and flash hard drives wear out over time.  Conventional hard drives wear out due to mechanical erosion whereas flash cells wear out due to electrical reasons. Reading tasks though are possible without any limitation. However, one flash cell can only take care of writing tasks between 3.000 (MLC 25nm) und 100.000 (SLC ) depending on the quality.  S.M.A.R.T. (Self-Monitoring, Analysis and Reporting) is a technology built into SSDs and hard drives for self monitoring and analysis purposes. By means of a special software, S.M. A.R.T values can be analysed and possible failure forecasts can be compiled. Consequently, a switch to read-only modus may occur.

M.2 is the physical form factor. SATA and PCIe are different bus standards used to communicate with the motherboard. An M.2 PCIe SSD will be much faster than an M.2 SATA SSD.

Please refer to your motherboard or system manufacturer documentation that came with your computer. It will inform you about the types of ports available on your motherboard and thus what SSDs you can use. You cannot tell by just looking at the port.

Non-volatile Memory Express (NVMe) is a protocol designed to optimise communication with non-volatile memory media (such as NAND flash and Persistent Memory). The low latency and parallelism inherent in the protocol make NVMe SSDs the fastest in the consumer SSD market.