Understanding WORM Functionality and its role within Data Storage

What is WORM functionality?

WORM stands for “Write Once, Ready Many.” It is a data storage technology that allows data to be written to a storage device once and then be read multiple times. Importantly, that data cannot be overwritten, erased, or altered in any way.

What are the advantages of WORM functionality?

Once stored on a WORM-compliant device, data becomes immutable, i.e., only authorized users can read it and nobody can change it. By rendering data immutable, WORM prevents bad actors from erasing or modifying critical data after it’s been stored—and prevents teams from accidentally doing the same.

This makes WORM highly advantageous for industries that are subject to strict data compliance requirements, including finance, healthcare, legal, government, and archiving. WORM ensures sensitive records are stored in a secure, immutable format that is compliant with regulatory requirements. Additionally, WORM functionality proves valuable for the distribution of copyright-protected data, such as PC and console games.

What are the four main WORM implementations?

There are four forms of WORM implementations, which are often used alongside other data storage technologies to ensure data integrity and longevity.

1. True/Physical WORM: on traditional tape drives that are never-ever erasable
2. Hardware WORM: on a flash controller through an activated e-Fuse bit
3. Firmware-Extension WORM: in the firmware on a flash controller
4. Software WORM: on the host OS

Physical WORM vs Software WORM: How do they differ?

True/physical WORM is the original technology, where WORM is implemented on tape drives.

Data is written to a tape with a specialized photosensitive coating. The tape is then heated by a laser, changing the physical state of the coating and permanently writing the data to the tape. Once “burned” to the tape, the data can never be erased, modified, or overwritten.

Software WORM is most often implemented in large-scale server settings.

Typically, software WORM attaches storage drives to a host system, using access rights to implement WORM functionality. The system administrator can then control what is written on the storage (though all administrator activity must be logged to ensure proof and non-repudiation).

What are the Pros and Cons of Physical and Software WORM

Today, true/physical WORM is no longer suitable for all use cases (e.g., holding personal data), as it may not conform with GDPR. (Hardware WORM and software- and firmware-extension WORM implementations can circumvent this issue.)

Software WORM, however, presents its own challenges. Because it allows each software vendor to vary their implementation, this approach is the most diverse in terms of quality and reliability.

In many cases, a firmware based WORM approach is a strong candidate. Compared to software WORM on the OS, a firmware-based approach is resistant to malware. Firmware WORM can also be used as removable media, which is not a possibility when WORM functionality is provided by the host. 

How can the NAND Flash Controller enables WORM functionality? 

There are two ways the NAND flash controller can enable WORM functionality:

1. In the hardware via an activated e-Fuse, which is a type of non-volatile memory with OTP (One-Time Programmable) capacity.
2. Through firmware extensions, where the controller’s firmware includes a write-protection flag.

One method of implementing write protection is to use a firmware-based approach. In this case, the flash controller firmware can implement a write-protection flag that is set when data is written to the memory. Once the write-protection flag is set, any attempts to modify or erase the data will be blocked by the controller. The benefits of a firmware-based approach in comparison to a software WORM on the OS is that it is resistant against malware on the host OS. Furthermore, it could be used as removeable media, which is not possible if the WORM functionality is given by the host.

Optimizing WORM with Hyperstone flash controllers: Why your choice of flash controller is so important.

As data threats continue to grow, WORM data storage is an increasingly attractive technology for industrial applications that demand robust data security and integrity. Considering the drawbacks of both true/physical WORM and software WORM, achieving optimal WORM functionality today is often with a firmware-based approach enabled by the flash controller.

Hyperstone’s flash controllers are designed with security customization and use case optimization in mind. Its API empowers engineers to develop individual, undisclosed firmware and enable WORM and other secure functionality in their drives. This allows teams to not only benefit from Hyperstone’s high-end flash management but also optimize their drive securely and independently from third parties to ensure reliable, immutable storage of critical data across applications.