ARM gives next-gen chips a memory boost

Posted by Aharon Etengoff

ARM recently confirmed that its next-gen processor cores will be capable of addressing up to 1TB of physical memory.

As Jonathan Angel of LinuxForDevices notes, the current generation of top-end ARM chips are based on 32-bit designs, and therefore limited to addressing a total of 4GB of RAM.

However, ARM is expected to significantly raise the (supported) core RAM limit by adding a feature known as LPAE - or large physical address extension.

"[The accompanying] operating system or hypervisor will be able to access up to a terabyte of main memory, thanks to a translation of 40-bit physical memory addresses to 32-bit virtual memory addresses," explained Angel.

"Essentially, LPAE will allow large amounts of RAM to be added while making the core 'think' it's just using a 4GB memory space."

Angel added that increased memory capabilities would definitely "come in handy," as future ARMv7-A cores have been tapped to simultaneously run multiple operating systems.

Indeed, a new 'Hyp' mode should allow hypervisors to exercise complete control of virtualized resources, while only "minimally" intervening in routine guest OS tasks.

"ARM [is also expected] to enable full virtualization solutions, where guest operating systems can run without change, [as well as] para-virtualization [scenarios], where guest software is expressly modified."