PinOS is an extension of the Pin dynamic instrumentation framework for whole-system instrumentation, i.e., to instrument both kernel and user-level code. It achieves this by interposing between the subject system and hardware using virtualization techniques. Specifically, PinOS is built on top of the Xen virtual machine monitor with Intel VT technology to allow instrumentation of unmodified OSes. PinOS is based on software dynamic translation and hence can perform pervasive fine-grain instrumentation. By inheriting the powerful instrumentation API from Pin, plus introducing some new API for system-level instrumentation, PinOS can be used to write system-wide instrumentation tools for tasks like program analysis and architectural studies. As of today, PinOS can boot Linux on IA-32 in uniprocessor mode, and can instrument complex applications such as database and web servers.

Emerging Web services, such as email, photo sharing, and web site archives, must preserve large volumes of quickly accessible data indefinitely into the future. The costs of doing so often determine whether the service is economically viable. We make the case that these applications' demands on large scale storage systems over long time horizons require us to reevaluate traditional system designs. We examine threats to long-lived data from an end-to-end perspective, taking into account not just hardware and software faults but also faults due to humans and organizations. We present a simple model of long-term storage failures that helps us reason about various strategies for addressing some of these threats. Using this model we show that the most important strategies for increasing the reliability of long-term storage are detecting latent faults quickly, automating fault repair to make it cheaper and faster, and increasing the independence of data replicas.