ITU team honoured for research paper on SSDs

Professor Phillippe Bonnet and his former PhD students Matias Bjørling and Javier Gonzalez were honoured for their work on Solid State Drives (SSDs) at the 9th Annual Non-Volatile Memories Workshop hosted by the University of California, San Diego.

Computer Science DepartmentResearchdata storagePhilippe Bonnet

The paper, ‘LightNVM: The Linux Open-Channel SSD Subsystem’  by Matias Bjørling, Javier Gonzalez  and Philippe Bonnet was one of six finalists for the Memorable Paper Award selected from over 80 papers submitted to the Non-Volatile Memories Workshop.

The workshop, which this year took place from March 11-13, is the world’s premier venue for research into how to use non-volatile memory technology to improve the performance, reliability, and efficiency of computing systems.  

The Memorable Paper Award is given annually to outstanding research published in the last two years that is expected to have substantial impact on the study of non-volatile memories. To be eligible, the paper must have been published in peer-reviewed venue in the last two years and the lead researcher must have been a student at the time.

This paper is based on the work that Matias Bjørling did during his PhD study at ITU and further developed together with Javier Gonzalez at CNEX Labs in Copenhagen. CNEX Labs is now working closely with Microsoft on Project Denali, which builds on the success of the LightNVM system presented in the paper.

Summary of the paper:

Solid State Drives (SSDs) have become the storage of choice in the cloud. Despite their success due to superior performance, SSDs suffer a well-documented problem: their performance degrades significantly, from time to time, in a way that is not predictable. Such latency variability causes delays for users that interact with online services. It is a key issue for cloud service providers.

This issue is not due to hardware limitations. Indeed, the non-volatile memory chips inside SSDs provide predictable high-performance. It is how tens of non-volatile memory chips are managed within a SSD that causes the problem. What is worse for cloud service providers, they do not control how SSDs are managed.

Open-Channel SSDs address this issue. They let hosts control the way data is placed and accessed on SSDs. This way, cloud service providers can make sure that different services accessing data on a same SSD in parallel, without interferences. We present LightNVM, the Open-Channel SSD subsystem in the Linux kernel. LightNVM is the first open, generic subsystem for managing Open-Channel SSDs. LightNVM provides a host-based Flash Translation Layer, called pblk, that exposes Open-Channel SSDs as traditional block devices. Our experimental results show that LightNVM achieves high performance and can be tuned to control latency variability. LightNVM has been part of Linux since 2016. The second version of the Open-Channel SSD Specification was released on January 29, 2018. You can follow progress on the software ecosystem as well as announcements of available hardware at

The full paper is available here.

Further information

Philippe Bonnet, Professor, email

Vibeke Arildsen, Press Officer, phone 2555 0447, email