Baidu rolls out world's first commercial deployment of Marvell ARM server | Hacker News Reader

Baidu rolls out world's first commercial deployment of Marvell ARM server

marvell.com

35 pointsEcio7810 comments

This article on El Reg gives a better overview I think, including mention of the 40-bit memory addressing on the Armada XP that has been commented on in here already.

http://www.theregister.co.uk/2013/02/20/baidu_marvell_arm_se...

Interestingly I noted that it supports 16GB DDR3 RAM. Since all current ARM cores are 32bit I wonder if they are doing some sort of bank switching to address all the RAM.

Apparently some Marvell CPUs have 64-bit address extension http://www.marvell.com/embedded-processors/armada-xp/

Most likely it's something like x86 PAE, where each process has a 32-bit address space and the page table just has a few extra bits to map into a >4GB physical address space.

I'm a little outside of my area of expertise, but didn't Intel late model 32-bit chips have a form of larger memory addressing? I thought I read somewhere that there was a greater-than-32-bit memory address setup in x86 architectures, but Microsoft products wouldn't take advantage of it, only Linux and other OSs were able to use it.

Even in a modern x86-64 bit architechture, you can do some limited 128 and 256 bit operations. This ARM may have a greater-than 32 bit memory addressing setup, but only support 32 bit opcodes for the main registers.

You're thinking of PAE. It allowed the system as a whole to use more than 4Gib, but it still limited a virtual memory space to 4GiB.

As others have said: with PAE. This is included in ARM's Cortex A15 Core, although AIUI Marvell use their own.