[Seminar] L4 Micro-Kernel and Beyond
■호스트: 민상렬 교수 ( x7047, 880-7047)
The Operating Systems Research of my group has as its core in L4-micro-kernel-based technology and its applications, some of which have been successfully transferred to commercial usage. I sketch some of these activities and current/future developments.
At the center of the technology are Hybrid Applications and Servers. They are split into components that run on the L4 micro-kernel, but use virtualized Linux for functionality that is complex but not critical. I shortly present the principle and some deployed applications in the domain of security-critical environments and narrate successes and failures, for example of what became known as "Merkel-Phone". Then I address two newer developments:
A major challenge for Hybrid Applications is the effort needed to port existing Linux-applications. An especially elegant way to keep that effort small is to "decouple" Linux processes, i.e. applications are started on Linux and then are decoupled from Linux to run on L4; whenever a Linux-Syscall is made, they are moving back to Linux automatically. Changes to the Linux application are only needed in places where direct L4 system calls are needed.
All usages of the technology require architectural support for isolation, namely user/kernel-mode and virtual memory. That leaves for (heterogeneous) accelerators their usage as devices, aka second class citizens. I present how a novel hardware/kernel architecture (that we called M3) in the spirit of L4-based systems overcomes that limitation and allows accelerators as first class citizens: accelerators directly access services such as a file service, can be augmented by Caches and Virtual Memory and can be chained for streaming applications.
In addition I shortly talk about the operating systems scene at the city of Dresden as it developed over the past years.