Pratap Subrahmanyam

The evolution of an x86 virtual machine monitor

Twelve years have passed since VMware engineers first virtualized the x86 architecture. This technological breakthrough kicked off a transformation of an entire industry, and virtualization is now (once again) a thriving business with a wide range of solutions being deployed, developed and proposed. But at the base of it all, the fundamental quest is still the same: running virtual machines as well as we possibly can on top of a virtual machine monitor. We review how the x86 architecture was originally virtualized in the days of the Pentium II (1998), and follow the evolution of the virtual machine monitor forward through the introduction of virtual SMP, 64 bit (x64), and hardware support for virtualization to finish with a contemporary challenge, nested virtualization.

Remote memory in the age of fast networks

As the latency of the network approaches that of memory, it becomes increasingly attractive for applications to use remote memory---random-access memory at another computer that is accessed using the virtual memory subsystem. This is an old idea whose time has come, in the age of fast networks. To work effectively, remote memory must address many technical challenges. In this paper, we enumerate these challenges, discuss their feasibility, explain how some of them are addressed by recent work, and indicate other promising ways to tackle them. Some challenges remain as open problems, while others deserve more study. In this paper, we hope to provide a broad research agenda around this topic, by proposing more problems than solutions.