Presented by Western Digital


Automakers continue to roll out vehicles outfitted with advanced driver assistance systems (ADAS) to help cars become safer, smarter, and more enjoyable. Vehicle operations now largely involve electronic systems centered around processors or system on chips (SoCs). Because of this, digital storage has moved into a more important role that is ramping up next-generation vehicles. Simply put, today’s modern cars — electric, self-driving, hybrid, autonomous, you name it — work as they do because of storage.

Data demands are expanding

The automotive market is driving storage growth. According to the NAND Quarterly Market Monitor, Q1 2021, from Yole Développement (Yole), automotive data demand will skyrocket. The market research and strategy consulting company, Yole, estimates the NAND-based automotive storage demand will increase to 4EB in 2021, and should jump to 24EB by 2024, rising further to 78EB by 2027. Autonomous Level 5 vehicles will only be a small percentage of the vehicle shipments in 2027, so the NAND storage growth will be driven mainly by L2-L4 vehicles, which will represent roughly 85% of vehicles shipped. The feature-rich L2-L4 vehicles will provide advanced levels of safety, connectivity, and entertainment — all requiring higher capacity storage. Overall, the anticipation is a 270% CAGR from 2019 to 2027.

Vehicles today are using more data for over-the-air updates, rich mapping systems, high-quality infotainment applications, and advanced driver assist systems that detect roadway activity.

Here’s what automakers should consider when implementing vehicle data storage.

The right storage is important

In the past, vehicles relied on storage for their infotainment systems — mainly for storing the OS and map data. But today, the use cases are very different and the architectures are changing so the type of storage needs to be carefully considered.

Automotive-grade storage is a must. Automotive-grade devices can withstand wider temperature ranges from -40C to 105C and have gone through a more stringent testing flow at the manufacturer making them less susceptible to physical failures.

There are also SD, e.MMC, UFS, and PCIe interfaces available. Which one to choose is in part dictated by the SoC and the interfaces it supports. It also comes down to performance requirements. If high performance is not a requirement, e.MMC will likely be your best choice because you can avoid the challenges of routing and signal integrity that come with high-speed designs.

UFS is the next step up in performance and is gaining popularity as storage capacity points increase with shared storage applications. PCIe is on the horizon and will definitely be an interface used to support the high performance needed in domains and zonal architectures.

Know your workload

Selecting the right capacity and interface are fairly straight forward, but one thing that is often overlooked is how the device will be written to. When vehicle systems are being designed, it is critical to calculate data workload accurately. The endurance of the storage device depends on the amount of data written, measured in terabytes written (TBW), and varies based on the capacity of storage. Every device has a limit, so it is important to determine the data write requirements based on real system workloads.

The write amplification factor (WAF) is an important consideration that is sometimes forgotten when calculating the system workload and TBW.

WAF is the amount of data that is actually written to the NAND versus the amount of data sent to the NAND by the system. There are several factors that affect the WAF but the main one is that data is written in pages and erased in blocks. Simply put, if a lot of random data is sent to the storage device, the pages might not be completely full causing “empty” space that is not fillable unless the data is moved and combined to another page, thus causing additional writes to free up space. Think defragmenting a hard drive to make space and make the HDD perform better. Similarly, this can happen in flash where data may need to be rewritten to different areas to free up storage space. This causes additional writes as data is moved about to maximize storage area and increases the WAF.

Serial data will provide basically a WAF of 1 since it is fills each page completely. What this means is that if 50TBs of data are sent from the host and the WAF is 3.0, the actual TBW to the NAND is 150TB.

There are things that can be done on the host side to reduce this, but if you were to calculate your useful life based on a WAF of 1.0 but it really was 3.0, your actual useful life would only be 1/3 of that and may cause the system to fail unexpectedly. This is just one example of why it is important to understand how your system will be accessing the storage device and analyzing its impact on the life of the product. You may not even be aware of some writes the system is doing. Taking traces and analyzing them will help better understand your work loads.

Digital storage drives innovation

Vehicles today are essentially computers on wheels that will become servers on wheels in the future. With a range of built-in sensors, cameras, and internal networks, they will be able to seamlessly detect everything that’s happening on the road —  including cars, cyclists, pedestrians, and street signs.

As cars continue to be upgraded with more advanced features, they will have smarter functions and technology that will require more storage and generate even more data. This is why proper data storage and knowing your workload is so critical.

Improved vehicle intelligence can help drivers stay steady on the road. ADAS and other features require a lot of application and operating system software that must be stored on reliable storage devices. Additionally, over-the-air (OTA) software updates from manufacturers can be pushed to add new features and benefits, which will increase the need for storage even more. This means that manufacturers will need to plan long term for additional storage space to handle the increased lines of software code.

Next big step

As cars develop more autonomous features and more amounts of data are created, the need for storage capacity and performance to manage all these applications requires strategic planning, careful coordination, and smart execution. We are still in the beginning of the next chapter for the automotive revolution. Within that, data storage’s role in enhancing how people travel will continue to increase.

Russel Ruben is Global Automotive Segment Marketing Director at Western Digital.


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