An in-depth look at embedded SSDs

Their architecture, devoid of mechanical parts, not only avoids device failures due to mechanical disturbances but also adopts swift data access. Indeed, it is vital in today's high-velocity information landscapes.

The industry's shift from 2D NAND to 3D NAND technology has notably enhanced SSD storage densities and read/write operations, with embedded SSDs leading this transition. A significant stride in this realm is the adoption of Triple-Level Cell (TLC) technology, which stores three bits of data per cell, providing a lower cost per gigabyte compared to Single-Level Cell (SLC) and Multi-Level Cell (MLC) flash. This makes TLC a cost-effective solution integrated in both enterprise and consumer-grade SSDs, digital cameras, mobile phones, and USB drives.

TLC's union with 3D NAND, where memory cells are stacked vertically, further amplifies storage densities while improving flash endurance. The shift from traditional floating-gate architecture to charge-trap architecture in TLC 3D NAND designs enhances endurance and reliability. This charge-trap architecture, employing a silicon nitride film to hold charged electrons, mitigates potential defects and charge disturbances. The amalgamation of TLC and 3D NAND technology in embedded SSDs showcases a balanced approach to achieving better storage capacities, improved performance, and cost-efficiency, addressing various storage needs in the evolving tech landscape.

Features of embedded SSDs

Form factor

The form factor determines the SSD's adaptability and deployment in various applications. The decision centres on necessities like hot-swappable function and physical dimensions. For example, while the 2.5” SSD offers flexibility and easy interchangeability, the M.2 is available in diverse sizes and presents a compact form, albeit without hot-swapping capabilities.

Storage capacity (including over-provisioning)

When evaluating embedded SSDs, you must understand their actual usable storage capacity. Manufacturers might specify the full flash size or partake in over-provisioning (OP). It is where some of the storage space is reserved for internal SSD management tasks like garbage collection. For instance, a 256GB SSD might only offer 240GB of usable space due to OP. The approach affects the performance and permanence of the SSD in high-demand applications while rendering it essential to scrutinize and test the SSD's real-world usable capacity.    

Example: SATA SSDs excel as boot drives and storage units, adhering to SATA-IO and JEDEC standards, and showcasing robust performance, especially in industrial scenarios.

Data rate (sequential read/write speed)

The data rate, particularly the sequential read and write speeds, is pivotal in determining how swiftly data can be accessed or written on the SSD. High sequential speeds are crucial for tasks that involve large file transfers or high-resolution video editing, ensuring swift data access and efficient operations.

Example: NVMe Embedded SSDs leverage the high-speed PCIe interface to boost data transfer speeds, significantly reducing latency.

Durability and lifespan

Endurance in SSDs is quantified using metrics like Terabytes Written (TBW) or Drive Writes Per Day (DWPD). These metrics indicate the limited amount of data that can be written onto the SSD over its lifetime. A higher TBW or DWPD value signifies a longer lifespan, making the SSD a more reliable choice for write-intensive applications.

A key feature contributing to an SSD’s durability is wear levelling. Each flash memory cell can withstand a finite number of program/erase (P/E) cycles before it becomes unreliable in storing data. This limitation affects the overall lifespan and endurance of the storage medium. Wear Levelling technology ensures a balanced distribution of write and erase cycles across the storage medium, thereby maximising its lifespan.

Example: The endurance of SATA Embedded SSDs, showcased by their TBW metric, makes them ideal for industrial-grade applications.

Wide operation temperature

Most of the embedded systems are in compact environments and endure heat dissipation challenges. Moreover, some applications are in harsh environments like outdoor or in-vehicle settings. The ability to operate reliably over a wide temperature range makes some SSDs well-suited for industrial, automotive, or outdoor applications where they are exposed to extreme temperature variations. Whether deployed in hot or cold climates, a broad operational temperature range ensures the SSD continues to function reliably.

Power loss protection and error correction

Embedded SSDs employ Power Loss Protection (PLP) technology, like Cervoz’s Powerguard, to maintain data integrity during power disruptions by using real-time detectors to identify power failures and activating integrated mechanisms to prevent data corruption. For instance, some SSDs use onboard capacitors to provide backup power during sudden outages, ensuring ongoing write operations are completed. Alongside, Error-Correcting Code (ECC) enhances data reliability by automatically detecting and correcting data corruption, which is vital in scenarios demanding high data accuracy. Together, PLP and ECC fortify the reliability and data integrity of embedded SSDs in various operational conditions.

Reliability and data integrity

For enhanced data integrity and reliability, integrating advanced error-correcting techniques like ECC (Error-Correcting Code) is crucial. ECC is integral for maintaining data integrity and reliability by detecting and correcting data corruption automatically. It's particularly important in environments where data accuracy is critical, ensuring that the data remains uncorrupted over time.

These added features underscore the robustness and versatility of embedded SSDs, making them a reliable choice for various demanding applications.

Applications of embedded SSDs

In this part, we will focus on the practical benefits of embedded SSDs through examples.

• High-Performance Computing (HPC) clusters: in computational genomics research clusters, embedded SSDs with NVMe interfaces accelerate the data throughput in handling massive genomic sequences. It boosts real-time data processing and analysis and streamlines the workflows involved in personalised medicine research
• Industrial automation and control systems: while traditionally SLC NAND technology has been favoured for its higher endurance in demanding environments, advancements in error correction and wear levelling mechanisms have expanded the applicability of embedded SSDs with TLC NAND technology in PLCs within manufacturing environments. This evolution allows TLC NAND to provide a cost-effective solution, ensuring dependable operation and real-time control processes in a variety of industrial settings, including those with high-temperature and high-vibration conditions
• Aerospace and defence: in modern avionic systems, embedded SSDs are needed in data logging and sensor data collection for consistent data write integrity and speed. Tailored with ruggedised features, these SSDs guarantee resilient performance under fluctuating temperatures and high-G operational loads dominant in aerospace missions
• Telecommunications infrastructure: for robust and proficient network operations in data centres managing telecommunication workloads, embedded SSDs elevate IO-intensive applications by reducing latency. Thus, it improves data retrieval times for real-time processing needs, including VoIP and video conferencing services
• Advanced Driver-Assistance Systems (ADAS) in automotive: embedded SSDs are used in vehicle ADAS, where rapid data access and writing capabilities are vital for real-time sensor and camera processing and analysis. It gives better sensitivity and accuracy in safety-critical functions like collision avoidance and lane departure warnings

Cervoz – industrial embedded SSD product line

Embedded SSDs represent the next phase in storage solutions and synthesis of durability and performance. While moving to these storage mediums, Cervoz's Industrial Embedded SSD product line is a focal point of exploration. It includes various types of Flash modules in diverse form factors, like mSATA, Half Size mSATA, Half Slim, M.2 2242/2280, PATA Disk 40/44pin, SATA Disk 7pin, and others. With their strength and consistency, they navigate the complexities of many industrial applications.

Cervoz deal with a diverse spectrum of embedded SSDs for many operational demands and challenges. Furthermore, products are available in several capacities and may be used in a regular or broad temperature range. They are handy for starting up devices and storing data. In essence, we prioritise compatibility, endurance, and usefulness, and our SSDs guarantee excellence and innovation.