Solid State Drives (SSDs)

Solid State Drives (SSDs)

Around the year 2008, a new class of devices began to partially replace the classic mechanical hard drive that was found in almost every computer up to that point: the SSD, or Solid-State Drive. Today, it is indispensable in any PC that is not used solely for basic tasks - the advantages of NAND flash-based SSDs over their counterparts with rotating magnetic disks are simply overwhelming. They are faster by orders of magnitude in both sequential transfer and, even more so, in reading and writing many small files. They are silent, consume less power, and without moving parts, are much more robust and shock-resistant.

However, they have one significant drawback - SSDs are considerably more expensive than HDDs for the same capacity. Although they are considered mass storage devices, really large amounts of data are still stored on hard drives for cost reasons - the smaller but faster SSDs are primarily used as system drives to give the operating system and programs a massive speed boost. But beware: once you've experienced a PC with an SSD, you might find computers without SSDs unbearably slow!

SSD / Solid State Drives - Different Form Factors, Controllers, Flash Chips, and Firmwares

Just like hard drives, SSDs come in different form factors and technical features tailored to their specific use cases. The variants differ based on the following characteristics:

• Form Factor: The standard form factor is the 2.5-inch format known from notebook hard drives with a height of 7 or 9.5 mm. These SSDs can therefore replace hard drives in notebooks or their 3.5-inch counterparts in desktop computers without further modifications. For notebooks, there are also very slim SSDs in mSATA or M.2 format, which are integrated into the device without a case and thus require significantly less space. In particularly fast desktop PCs and workstations, SSDs in the form of PCIe expansion cards are also used, which are significantly faster but also more expensive than regular SATA SSDs.
• Connection: While most solid-state drives use a regular SATA connection with 3 or 6 Gb/s, there are also those with a SAS connection for professional use and the aforementioned PCI-Express SSDs. In notebooks, the related mSATA interface is used and, in the future, also SATA Express, which is nothing other than the direct connection of the SSD via PCI-Express lanes.
• NAND Flash and Controller: Most models are based on MLC flash, which can store 2 bits per cell. Models with expensive but fast SLC memory (1 bit per cell) are becoming increasingly rare, while TLC models with 3 bits per cell and high data density are finally leading to lower prices and very large available capacities. Controllers from LSI Sandforce, OCZ/Indilinx, Marvell, Samsung, and Intel are frequently used.
• Firmware: The manufacturer can make adjustments through the firmware to optimize for specific applications, such as database applications. Furthermore, over-provisioning, which is the additional, not directly usable storage space, can increase the lifespan of the SSD by providing more reserve flash cells.