The realities of minimalism.
There isn't much to go on here, and a search for +Mendel +Rosenblum "virtual client" doesn't reveal much. Did that man just say "remove the OS and replace it with VMware"?
Well - if you really wanted to, you can do it now. Strip down your Xen-based, paravirtualised FreeBSD or Linux kernel so it's just a scheduler, a memory mapper and a filesystem. Virtualize your storage with a whatever appliance or SAN, and just boot Oracle over that very thin layer.
Okay, you could make a whole new lightweight framework for plugging in just those things. And of course Andy Tanenbaum will love this notion. And of course we're practically there already. Oracle plug their ocfs2 into Linux quite nicely.
The trouble with the minimalist approach starts when you want to manage needs that accumulate in production. Suddenly you start to need filesystem management tools, debuggers, profilers, scripting languages, SNMP services, compilers, test harnesses, firewalls, volume management, development tools and so forth. And before you know it you've got a general-purpose OS. And it's not so bad, because you're getting work done. But why reinvent that wheel? For each new application? Sounds like a an exercise in accumulating multiple, inconsistent system management models like moss.
I realise that being a Professor doesn't have anything to do with the dirty intricacies of managing real-world production systems. In this case it sounds like an compulsion to creating the cleanest possible software stack, hang the consequences and realities. Which I'm sure we all recognise as a classic nerd urge. And I'm sure every manager recognises as a problem, not a solution.
Still, his point seems moot. With good packaging models you *can* strip it an existing system down almost trivially. And if you have a competent sysadmin they can do this now with Solaris, BSD, Linux - at both userland and kernel level. And with a braver admin, with Win2003.