Institut für Betriebssysteme und Rechnerverbund

Promotion Jan Schlichter

Am 14. August 2025 hat Jan Schlichter seine Promotion mit der Verteidigung seiner Dissertationsschrift erfolgreich abgeschlossen.

ParPerOS: Second Funding Phase confirmed

The DFG has approved the second funding phase of ParPerOS. ParPerOS explores novel operating system mechanisms for parallel and persistent main memory technologies. It is part of the DFG Priority Programme SPP 2377 – Disruptive Memory Technologies, which investigates the systematic integration of emerging memory technologies into computer architectures, operating systems, and applications.

Cumulus: DFG Funding confirmed

The DFG has confirmed funding the project Cumulus, a collaboration with Viktor Leis. It pioneers unikernel-based OS kernels co-designed with cloud-native database systems. Unikernels streamline performance by collapsing isolation barriers: no system-call overhead, full hardware access, leaner code. This unlocks a fresh chance to reimagine and revive beyond-their-time POSIX abstractions and craft novel, high-performance OS–DB interfaces for the cloud era.

VSS@EuroSys'25: Fast Shrinking and Growing of Virtual Machines

In our paper, HyperAlloc: Efficient VM Memory De/Inflation via Hypervisor-Shared Page-Frame Allocators, presented at the renowned EuroSys conference, we address a major challenge in virtualization—provisioning the right amount of DRAM to virtual machines (VMs). Many VMs face highly volatile memory demands, leading to either overprovisioning or poor quality of service during peak demand. While techniques like memory hotplugging and ballooning exist, they often fail to be DMA-safe or flexible enough.

We introduce HyperAlloc, a DMA-safe memory reclamation technique that significantly accelerates VM de/inflation, shrinking virtual machines up to 362 times faster the state of the art. HyperAlloc’s automatic memory reclamation also reduces the average memory footprint of a virtual machine by 17% compared to existing methods.