What is Storage Class Memory (SCM)? What is SCM Memory?

It is likely that in recent times you have heard of storage class memory or SCM memory, a new type of memory that is postulated between DRAM and NAND in terms of performance, resistance and cost.

SCM memory

In this article we are going to tell you what SCM memory is, how it works and how it differs from NAND and DRAM.

There are many types of memory that are used today. Starting with the processor caches, which are the fastest, and ending with the ones we use in traditional hard drives, there are a multitude of intermediate steps, all with a specific performance, density and manufacturing cost. In the following graph prepared by WD you can see where this storage class memory is located, which we are going to talk about today.

What is SCM memory? SCM stands for Storage Class Memory, as we indicated at the beginning. It is a type of memory whose main faculty is that it includes a power source to ensure that data is not lost when there is a system error or when the power goes out.

Therefore, it is a type of non-volatile memory but it has the peculiarity that it treats the data as if it were normal DRAM memory, and the difference lies in that, that the data is not lost if there is a power cut.

In terms of performance, the SCM memory is placed between the RAM and the Flash NAND of the SSDs, and thanks to this combination there are many types of SCM that are under development by the companies that are dedicated to storage, since many believe that it will be the basis for the digital transformation of how data is stored in computers.

Memory type hierarchy – As you can see from the image memory hierarchy pyramid, SCM memory is considered “memory” as such and not storage (despite its name). In essence, and for us to understand each other, it is a type of memory faster than SSDs but not as much as DRAM, but unlike the latter, it behaves like an SSD in terms of data persistence, that is, it is not volatile.

Storage class memory is a form of storage that is created from NAND Flash. It is an intermediate step between high-performance DRAM and normal hard drives, which are the cheapest to manufacture. It can provide much faster write performance than hard drives, and DRAM-like read performance.

SCM is considered an important component for high-speed data transfers, next-generation in-memory computing, and scale-out clusters for computing and storage.

In some cases, SCM can even be used to replace RAM, albeit logically at slower speeds. In this role, SCM can offer a number of benefits, including much faster restarts on database servers during scheduled maintenance, as well as during power problems and unexpected machine restarts.

Many applications and databases, especially those that require low latency, high durability, and strong data consistency, can take advantage of storage-class memory.

In addition, it also has the potential to accelerate virtual machine storage and deliver better performance to cloud applications that are spread across multiple nodes.