Auflistung nach Autor:in "Lohmann, Daniel"
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- KonferenzbeitragArchitecture challenges for internal software ecosystems: A large-scale industry case study(Software-engineering and management 2015, 2015) Schultis, Klaus-Benedikt; Elsner, Christoph; Lohmann, DanielThe idea of software ecosystems encourages organizations to open software projects for external businesses, governing the cross-organizational development by architectural and other measures. Even within a single organization, this paradigm can be of high value for large-scale decentralized software projects that involve various internal, yet self-contained organizational units. However, this intra-organizational decentralization causes architecture challenges that must be understood to reason about suitable architectural measures. In our FSE paper, we present an in-depth case study on collaboration and architecture challenges in two of these large-scale software projects at Siemens. We performed a total of 46 hours of semi-structured interviews with 17 leading software architects from all involved organizational units. Our major findings are: (1) three collaboration models on a continuum that ranges from high to low coupling, (2) a classification of architecture challenges, together with (3) a qualitative and quantitative exposure of recurring issues along each collaboration model. We identified compliant software development as the core challenge. It targets cross-cutting regulations and architecture governance to assist and check for compliance. In addition to our study results, we outline a framework along with tool support that allows to manage these regulations and their violations throughout the life cycle. Internal Software Ecosystems We have investigated two large-scale software projects (about 500 and 950 developers) within Siemens [SEL14]. These projects involve a set of internal organizational units that are self-contained profit centers with own business objectives, organizational independent with own product management, and have to a wide extent autonomous processes and software-engineering life cycles. Thus, the view on the organizational structure moves from strict hierarchies towards more decentralized topologies. We define those systems as internal software ecosystems (ISECOs) [SEL14]. ISECOs comprise a keystone organizational unit that provides a platform and multiple client organizational units that build applications upon it. The keystone acts in a creative role but does not have power to direct. Our talk is laid out as follows: First, we outline our study results. Second, we present our current work, a framework that addresses the compliant software development challenge. 114 Case Study Results:
- KonferenzbeitragFail*: towards a versatile fault-injection experiment framework(ARCS 2012 Workshops, 2012) Schirmeier, Horst; Hoffmann, Martin; Kapitza, Rüdiger; Lohmann, Daniel; Spinczyk, OlafMany years of research on dependable, fault-tolerant software systems yielded many tool implementations for vulnerability analysis and experimental validation of resilience measures. We identify two disjoint classes of fault-injection (FI) experiment tools in the field, and argue that both are plagued by inherent deficiencies, such as insufficient target state access, little or no means to switch to another target system, and non-reusable experiment code. In this article, we present a novel design approach for a FI infrastructure that aims at combining the strengths of both classes. Our FAIL* experiment framework provides carefully-chosen abstractions simplifying both the implementation of different simulator/hardware target backends and the reuse of experiment code, while retaining the ability for deep target-state access for specialized FI experiments. An exemplary report on first experiences with a prototype implementation based on existing X86 and ARM simulators demonstrates the tool's versatility.
- KonferenzbeitragFailure by design: Influence of the RTOS interface on memory fault resilience(INFORMATIK 2013 – Informatik angepasst an Mensch, Organisation und Umwelt, 2013) Hoffmann, Martin; Dietrich, Christian; Lohmann, DanielSoft errors are emerging with the ongoing reduction of structure sizes in current and future hardware designs. This problematic is generally tackled by employing fault detection or tolerance measures from an applications' point of view. At the same time, research commences to harden the operating system, often considered as remaining single point of failure. Certainly, these measures can effectively treat the symptoms of hardware faults. However, we argue that the operating system design per se can offer an intrinsic resilience against errors. Dynamic operating system designs, often resembling Unix-like interfaces, are obliged to cope with pointers and list-based data structures to provide the demanded flexibility. In contrast, especially in the domain of embedded systems this flexibility is often not needed. Here, static system designs can be deployed, which allow to avoid error-prone pointer-based memory operations. We believe, that a fully static system design can enhance the resilience against memory errors solely by reduced memory consumption and inherently more robust data structures. This paper studies the influences of memory faults on both, a dynamic and a fully static embedded operating system. Extensive injection campaigns, covering the entire fault space within the kernel data structures, will show that even when applying hardware-based fault detection mechanisms to a dynamic kernel, a static kernel design is still more than 75 percent less susceptible to silent data corruptions.
- KonferenzbeitragEine Infrastruktur für modellgetriebene hierarchische Produktlinien(Software Engineering 2009, 2009) Elsner, Christoph; Lohmann, Daniel; Schwanninger, ChristaDie Entwicklung von Software durch den Produktlinienansatz hat zu beachtlichen Effizienzsteigerungen geführt. Die klassische Vorgehensweise stößt jedoch an Grenzen, wenn sehr breite Produktportfolios abgedeckt werden sollen. In großen Unternehmen ergeben sich daher zunehmend so genannte hierarchische Produktlinien, bei denen auf einer Basisplattform je nach zu entwickelnder Produktgruppe weitere Produktlinienplattformen aufsetzen. Diese stellen sowohl in organisatorischer als auch in technischer Hinsicht Herausforderungen im gesamten Software-Lebenszyklus. Um die Variabilität in der Anforderungsspezifikation, der Architektur und der Implementierung einer solchen Produktlinie zu verknüpfen, stellen wir in dieser Veröffentlichung unser Konzept der modellgetriebenen hierarchischen Produktlinie vor. Um deren einfache Entwicklung zu ermöglichen, beschreiben wir zudem unseren Ansatz einer generischen Infrastruktur, welche die Entwicklung von modellgetriebenen hierarchischen Produktlinien unterstützt.
- KonferenzbeitragThe List is the Process: Reliable Pre-Integration Tracking of Commits on Mailing Lists(Software Engineering 2020, 2020) Ramsauer, Ralf; Lohmann, Daniel; Mauerer, WolfgangInternational Conference on Software Engineering 2019, Technical Track. Artifact evaluation: available and evaluated. Code+Data available as reproducible OSS. Research on software evolution often focuses on mining changes in software repositories, but omits their pre-integration history. Our work allows for tracking this invisible evolution of software changes on mailing lists (used by many low-level system components) by connecting all early revisions of changes to their final version in repositories. Since only updates to fragments (i.e., patches) are available, identifying semantically similar changes is a non-trivial task that we solve language-independently. We evaluate our method on high-profile OSS projects like the Linux kernel, and validate its high accuracy using an elaborately created ground truth. Our approach can quantify properties of OSS development processes, which is an essential requirement for using OSS in reliable or safety-critical industrial products. We can also quantitatively determine if an open development process effectively aligns with given formal process requirements. We will report on integration of our results in workflows of the Linux Foundation, one of the largest non-profit technology consortia for open source, and joint work with the automotive industry to deploy our results in practise.
- TextdokumentSilentium! Run-Analyse-Eradicate the Noise out of the DB/OS Stack(BTW 2021, 2021) Mauerer, Wolfgang; Ramsauer, Ralf; Lucas, Edson; Lohmann, Daniel; Scherzinger, StefanieWhen multiple tenants compete for resources, database performance tends to suffer. Yet there are several scenarios where guaranteed sub-millisecond latencies are crucial, such as in real-time scenarios, IoT, or when operating in safety-critical environments. In this paper, we study how to make query latencies deterministic in the face of noise (whether caused by other tenants or unrelated operating systems tasks). We perform controlled experiments with an in-memory database in a multi-tenant setting, where we successively eradicate noisy interference from within the system software stack, to the point where the engine runs close to bare-metal on the underlying hardware. We show that we can achieve query latencies comparable to the database engine running as the sole tenant, but without noticeably impacting the workload of competing tenants. We discuss these results in the context of ongoing efforts to build custom operating systems for database workloads, and point out that for certain use cases, the margin for improvement is rather narrow. In fact, for scenarios like ours, existing operating systems might just be good enough, provided that they are expertly configured. We then critically discuss these findings in the light of a broader family of database systems (e.g., including disk-based), and the technological disruption of the advances in modern hardware.