Memory health monitoring software supplies protection for SSDs

Solid State Disks Limited (SSDL) provides health monitoring software for use with its new solid-state-based removable media assemblies (RMAs).

The software is Windows-based and monitors the number of PE cycles executed and the number of remaining spare blocks. These contribute to an overall percentage, with 100% denoting healthiest.

“Although solid-state memory is inherently more reliable than rotating disk technology, it will eventually fail, largely as a result of memory wear,” comments Brian McSloy, SSDL’s chief technology officer. “Specifically, NAND memory will only support a finite number of Program-Erase, or PE, cycles.”

The company will be supplying the NATO Airborne Early Warning and Control Force (NAEW&CF) with the software on its AWACS aircraft. Whereas the original AWACS RMAs used electromechanical HDDs, that were over 20 years old and no longer produced, the new RMAs (supplied by the company) employ removable NAND-based CFast cards for data storage.

Card health is also denoted through a colour scheme the software’s GUI uses, with green indicating healthiest. As the card’s remaining life shortens, the GUI’s colour changes, with amber reflecting wear, but no immediate action is needed. Red indicates that the monitoring frequency should be increased, and a replacement card should be procured. Black warns the user that the card has failed or is about to fail.

“Helping prolong the life of the CFast cards is the fact that they employ single-level cell NAND Flash technology,” adds McSloy. “This means up to 100,000 Program-Erase cycles should be possible. The cards we supply err on the side of caution, though, and we state up to 60,000 PE cycles. However, for important applications, it is wise not to be overly reliant on theoretical or even advised PE cycle limits, and our software enables users to retire wearing cards in plenty of time.”

The CFast health monitoring software developed by the company builds on SMART, which was developed for computer HDDs in the 1980s and was subsequently expanded to cater for SSDs and their failure modes.

“The monitoring software we developed for NATO provides a view into the health of the solid-state memory that the operator never had with their old HDD-based RMAs,” concludes McSloy, “Also, our software can be repurposed and made user-bespoke for many other high-security applications in which solid-state memory is relied upon.”