Sony confirmed a while back that the PS5 would be backward compatible with PS4 software, and since then, they’ve spoken about how important that functionality is going to be their new system, and how they plan to use it to bridge the gap between two generations for new consumers.
In a patent that was filed by them a couple years ago, but was published only recently, they’ve spoken about how they plan on going about it. More specifically, the patent focuses on the issues that often arise with systems that attempt backward compatibility due to the differences in their hardware, and that of the system whose native software they attempt to run, and how Sony plans to address this issue with the PS5.
“Differences in performance of the hardware components of a new device and a legacy device can cause errors in synchronization on the new device, which may cause a legacy application to crash or produce incorrect output when running on a new device architecture,” the patent explains. “Such differences in performance can arise, e.g., from differences in hardware architecture between the new and legacy devices.”
Sony plans to enable developers to run old games on new hardware without altering the game’s base code, while also not having to sacrifice anything in performance, to essentially achieve the same (or similar) performance as the games did on the older hardware they natively ran on. This, as per the patent, can be done by tuning several operating parameters of the new hardware, including things such as the clock frequencies of the new device, the number of available general purpose registers (GPRs), instruction launch rates, and more.
“The performance of an application on a new device may be closely matched to the performance of that same application on the legacy device by tuning the operating parameters of the new device,” the patent explains. “Examples of operating parameters include, among other things, the clock frequencies of the new device, the number of available general purpose registers (GPRs), instruction launch rates, and the like. The application may be run repeatedly on the new system while tuning its operating parameters to adjust the application-specific performance characteristics.
“After a sufficient number of tests on the new system one can analyze how the performance characteristics of the application on the new system converge as the operating parameters change. A new set of operating parameters can be created based on the convergence analysis. This process may be repeated until the operating parameters are set optimally for the application on the new system. To further optimize, one can adjust the execution of the new hardware to see if the application can be run faster on the new hardware without causing it to fail.”
This isn’t the first patent for backward compatibility filed by Sony and lead PS5 architect Mark Cerny. Previous patents have spoken about automatic upscaling, ID spoofing, and enhanced simulation.