The Industrial Internet of Things and Industry 4.0 is getting closer and closer to us, and they are bringing disruptive changes and the need for reliable data storage, which is ultimately increasing the number of SSDs in the industrial storage sector significantly. The needs of each component within an industrial SSD are very different to those within a consumer product. Interestingly, most of these differences are addressed by one key component: the flash memory controller inside the SSD.
The flash controller in an industrial SSD must support advanced flash management to ensure more robust operation and longer-lasting data through lower write amplification factors, higher data integrity, and higher data retention rates. End-to-end data path protection provides a further way to ensure data integrity across the entire processing block. Protection against unauthorized access is another important feature of industrial SSDs. This is provided by encrypting data in accordance with the Advanced Encryption Standard (AES) and supporting the Self-Encrypting Drive (SED) standard TCG Opal. Most consumer SSDs come with TLC or 3D QLC NAND flash memory. While most people still believe that industrial SSDs should come with SLC or 3D MLC NAND flash, this is not absolutely necessary. SLC NAND flash is chosen because of its high endurance and retention compared to TLC NAND flash, especially in environments exceeding the commercial temperature range from 0°C to 70°C. However, the growing demand for storage capacity often requires the use of lower-cost technologies --SLC flash memory may simply not have the required capacity or the initial price may not seem competitive. Nevertheless, specific flash controllers support a feature that allows it to operate MLC or 3D TLC flash with comparable persistence and data retention to SLC flash - a mode called pseudo-SLC (pSLC). It opens up the possibility of selecting MLC or TLC flash, but at the same time, operates close to the availability of SLC flash. Sophisticated controllers support a pseudo-operation mode that trades reliability for capacity.
One of the most important features of industrial SSDs is power failure robustness. Embedded devices in industrial environments are not expected to be affected by sudden power failures and to maintain data integrity during such events. High-quality controllers implement a range of internal voltage sensors that monitor the power supply. Depending on the manufacturer, this can be configured individually for each application. If in the event of a power failure, the power supply falls below a configured threshold, the firmware will immediately activate the flash write protect trigger and take further action to protect the data and set the application to a safe shutdown. Again, the flash controller is responsible for handling such events, which is the essential difference between it and consumer devices. Although flash memory comes in different sizes, interfaces and capacities, the technology behind it is the same. By design, it is inherently unreliable, and the redundancy of the controller and flash memory ultimately determines the lifecycle and quality of the SSD. This is why industrial SSDs must be compatible with the latest flash memory, offer highly reliable modes of operation, robust error correction units, and advanced flash redundancy management.