Operating System Behavior Research Articles

The Influence of Temporal Disturbances in EKF Calculations on the Achieved Parameters of Flight Control and Stabilization of UAVs.

This article investigates the causes of occasional flight instability observed in Unmanned Aerial Vehicles (UAVs). The issue manifests as unexpected oscillations that can lead to emergency landings. The analysis focuses on delays in the Extended Kalman Filter (EKF) algorithm used to estimate the drone's attitude, position, and velocity. These delays disrupt the flight stabilization process. The research identifies two potential causes for the delays. First cause is magnetic field distrurbances created by UAV motors and external magnetic fields (e.g., power lines) that can interfere with magnetometer readings, leading to extended EKF calculations. Second cause is EKF fusion step implementation of the PX4-ECL library combining magnetometer data with other sensor measurements, which can become computionally expensive, especially when dealing with inconsistent magnetic field readings. This can significantly increase EKF processing time. The authors propose a solution of moving the magnetic field estimation calculations to a separate, lower-priority thread. This would prevent them from blocking the main EKF loop and causing delays. The implemented monitoring techniques allow for continuous observation of the real-time operating system's behavior. Since addressing the identified issues, no significant problems have been encountered during flights. However, ongoing monitoring is crucial due to the infrequent and unpredictable nature of the disturbances.

SABDTM: Security-first architecture-based dynamic trusted measurement scheme for operating system of the virtual computing node

In the cloud environment, the virtual computing node has become the dominant form of cloud services used by users. Hence, it is increasingly critical to guarantee the trusted operation of the virtual computing node's operating system (VCNOS). However, previous schemes suffer a lot, such as insufficient consideration of the comprehensive of the measured objects, ignoring the dynamic of trusted, and the trusted measurement mechanisms rarely consider their security. Thus, a three-dimensional dynamic trusted measurement model SABDTM, which integrates the integrity measurement of kernel static data, trusted evaluation of operating system behavior (OSB), and the feedback trust of interacting nodes, is proposed. First, SABDTM divided OSB into multiple atomic behaviors and introduced the Bayesian decision theory to predict trusted expectations of OSBs. Second, the feedback trust of interacting nodes is considered to improve the comprehensiveness of the trusted measurement and evaluate its value based on the Euclidean distance function to reduce the impact of inaccurate feedback from malicious nodes. Subsequently, we set the appropriate weight for trusted measurement values of different moments based on Induced Ordered Weighted Averaging to accurately portray the actual state of VCNOS. Moreover, we designed a lightweight and independent subsystem to perform the trusted measurement, which guarantees the security of the measurement service. The security of our model is proved rigorously based on the non-interference theory. Finally, the experiments and comparative analysis demonstrated our model has better functionality and superiority.

Execution trace‐based model verification to analyze multicore and real‐time systems

AbstractAs a key part of model‐driven development, modeling allows users to represent the application workflow or to automatically generate source code. This is convenient for developers, particularly to create or improve real‐time applications embedded in complex systems. Multicore systems are difficult to debug because the concurrently running processes can interfere with each other. In real‐time systems, timing constraints add to the complexity, invalidating results when a deadline is missed. Tracing is usually the most accurate and reliable tool to study the runtime behaviour of those applications. However, the interpretation of voluminous detailed execution traces requires a deep understanding of the operating system and application behaviour, and time to dig through the millions of trace events.In this paper, we present the use of model‐based constraints on top of user‐space and kernel traces to provide weighted analysis results. Our algorithms have been applied to multiple traces showing common problems for multi‐core real‐time systems. The experimental results show that our algorithms can quickly identify many different types of problems with a low runtime, even for traces with millions of events, thus helping to save time when analyzing thousands of trace events for complex systems.

Error Detection and Correction System (EDAC) of On Board Data Handling (OBDH) in Real Time Operating System Behaviour

The satellite requires the support of a robust sub system. On Board Data Handling (OBDH) is the core function of the satellite subsystem and has to be error free in managing the operation of the satellite. It should withstand the harsh environmental conditions in space that has a lot of hazards caused by radiations. In view of these two conditions, the OBDH design should be able to manage the operation and overcome the hazards of radiation. In order to manage the operation Real Time Operating System (RTOS) was applied. RTOS was able to manage the task efficiently and effectively. In the aerospace domain, RTOS has become popular because of its strength in managing the operating system. Error Detection and Correction System (EDAC) system was applied to make OBDH more robust. This paper discusses the implementation of the EDAC system in tandem with the RTOS behaviour to manage the operation and increase the robustness of the system. The findings show that OBDH can be programmed successfully using RTOS to handle critical and robust operations.

Автоматизация обнаружения и анализа ошибок в гиперконвергентных системах

The paper is devoted to the problem of early error detection and analysis in hyperconverged systems. One approach to organizing hyperconverged systems is to install on each physical server a separate instance of an operating system (OS) that carries virtualization tools and tools for administering and using a distributed data warehouse. Errors can occur both at the level of a single OS instance and at the level of the entire cluster. For example, incorrect control element commands from one infrastructure node can cause software failure on another node. In addition, errors from the subsystems of the cluster can provoke abnormal situations inside virtual machines. The complexity of the architecture of hyperconverged systems makes it difficult to analyze the errors that occur in them. To simplify such an analysis and increase its effectiveness, it is necessary to automate the process of detecting problems and collecting data necessary for their study and correction. Existing approaches for automation of error detection are described and various improvements are suggested to adopt them for systems where distributed storage and virtualization technologies are actively used. Improvements include log collection from the whole cluster just after the error occurred, additional analysis of guest operating system behaviour inside virtual machines, usage of a knowledge base for automated crash recovery and duplicate detection. Finally, a real-life scenario of error handling process in Virtuozzo company products is described starting from error detection and ending with fix deployment.

Ransomware behavioural analysis on windows platforms

Ransomware infections have grown exponentially during the recent past to cause major disruption in operations across a range of industries including the government. Through this research, we present an analysis of 14 strains of ransomware that infect Windows platforms, and we do a comparison of Windows Application Programming Interface (API) calls made through ransomware processes with baselines of normal operating system behaviour. The study identifies and reports salient features of ransomware as referred through the frequencies of API calls.

Error Detection and Correction System (EDAC) of On Board Data Handling (OBDH) in Real Time Operating System Behaviour

The satellite requires the support of a robust sub system. On Board Data Handling (OBDH) is the core function of the satellite subsystem and has to be error free in managing the operation of the satellite. It should withstand the harsh environmental conditions in space that has a lot of hazards caused by radiations. In view of these two conditions, the OBDH design should be able to manage the operation and overcome the hazards of radiation. In order to manage the operation Real Time Operating System (RTOS) was applied. RTOS was able to manage the task efficiently and effectively. In the aerospace domain, RTOS has become popular because of its strength in managing the operating system. Error Detection and Correction System (EDAC) system was applied to make OBDH more robust. This paper discusses the implementation of the EDAC system in tandem with the RTOS behaviour to manage the operation and increase the robustness of the system. The findings show that OBDH can be programmed successfully using RTOS to handle critical and robust operations.

Impact of Operating System Behavior on Battery Life

Impact of Operating System Behavior on Battery Life

Checking process-oriented operating system behaviour using CSP and refinement

Process orientation is an approach to concurrency that uses concepts of processes and message-passing communication, with whole systems constructed from layered and dynamically evolving networks of communicating processes. The work described in this paper relates to the automatic model generation and verification of systems developed in processoriented languages. We discuss some early applications of this technique to our experimental operating system, RMoX, as a means to giving a guarantee of correct system behaviour at a range of levels.

Tracing Time Operating System State Determination

In recent years, tracing operating system behavior by recording kernel events has proven to be a particularly ef- fective tool. However, when used to characterize the system's behavior through time, including its state, the list of state transitions that the kernel events represent is not sufficient to characterize the state for the entire data acquisition period. The initial operating system state, when tracing starts, is also required. The challenge lies in obtaining a complete snapshot of the initial state, while minimizing the impact on the system being traced. This impact may be in terms of CPU or disk I/O consumption, instrumentation memory, or burst activity at trace start time detrimental to the real-time response. Such impact is especially disturbing on small real-time limited resources embedded systems. In this paper, we will propose an efficient approach to extract such initial state information and discuss the software mod- ule we have developed to provide the aforementioned data to the LTTng tracing tool and its accompanying viewer, LTTV. This module not only improves LTTV's accuracy by providing the initial state of all processes in the system, but also pro- vides an inventory of relevant kernel objects at minimal cost, without increasing noticeably the interrupt latency.

An analysis of operating system behavior on a simultaneous multithreaded architecture

This paper presents the first analysis of operating system execution on a simultaneous multithreaded (SMT) processor. While SMT has been studied extensively over the past 6 years, previous research has focused entirely on user-mode execution. However, many of the applications most amenable to multithreading technologies spend a significant fraction of their time in kernel code. A full understanding of the behavior of such workloads therefore requires execution and measurement of the operating system, as well as the application itself.To carry out this study, we (1) modified the Digital Unix 4.0d operating system to run on an SMT CPU, and (2) integrated our SMT Alpha instruction set simulator into the SimOS simulator to provide an execution environment. For an OS-intensive workload, we ran the multithreaded Apache Web server on an 8-context SMT. We compared Apache's user- and kernel-mode behavior to a standard multiprogrammed SPECInt workload, and compared the SMT processor to an out-of-order superscalar running both workloads. Overall, our results demonstrate the microarchitectural impact of an OS-intensive workload on an SMT processor and provide insight into the OS demands of the Apache Web server. The synergy between the SMT processor and Web and OS software produced a greater throughput gain over superscalar execution than seen on any previously examined workloads, including commercial databases and explicitly parallel programs.

An analysis of operating system behavior on a simultaneous multithreaded architecture

This paper presents the first analysis of operating system execution on a simultaneous multithreaded (SMT) processor. While SMT has been studied extensively over the past 6 years, previous research has focused entirely on user-mode execution. However, many of the applications most amenable to multithreading technologies spend a significant fraction of their time in kernel code. A full understanding of the behavior of such workloads therefore requires execution and measurement of the operating system, as well as the application itself.To carry out this study, we (1) modified the Digital Unix 4.0d operating system to run on an SMT CPU, and (2) integrated our SMT Alpha instruction set simulator into the SimOS simulator to provide an execution environment. For an OS-intensive workload, we ran the multithreaded Apache Web server on an 8-context SMT. We compared Apache's user- and kernel-mode behavior to a standard multiprogrammed SPECInt workload, and compared the SMT processor to an out-of-order superscalar running both workloads. Overall, our results demonstrate the microarchitectural impact of an OS-intensive workload on an SMT processor and provide insight into the OS demands of the Apache Web server. The synergy between the SMT processor and Web and OS software produced a greater throughput gain over superscalar execution than seen on any previously examined workloads, including commercial databases and explicitly parallel programs.

An analysis of operating system behavior on a simultaneous multithreaded architecture

This paper presents the first analysis of operating system execution on a simultaneous multithreaded (SMT) processor. While SMT has been studied extensively over the past 6 years, previous research has focused entirely on user-mode execution. However, many of the applications most amenable to multithreading technologies spend a significant fraction of their time in kernel code. A full understanding of the behavior of such workloads therefore requires execution and measurement of the operating system, as well as the application itself.To carry out this study, we (1) modified the Digital Unix 4.0d operating system to run on an SMT CPU, and (2) integrated our SMT Alpha instruction set simulator into the SimOS simulator to provide an execution environment. For an OS-intensive workload, we ran the multithreaded Apache Web server on an 8-context SMT. We compared Apache's user- and kernel-mode behavior to a standard multiprogrammed SPECInt workload, and compared the SMT processor to an out-of-order superscalar running both workloads. Overall, our results demonstrate the micro-architectural impact of an OS-intensive workload on an SMT processor and provide insight into the OS demands of the Apache Web server. The synergy between the SMT processor and Web and OS software produced a greater throughput gain over superscalar execution than seen on any previously examined workloads, including commercial databases and explicitly parallel programs.

Tradeoffs in supporting two page sizes

As computer system main memories get larger and processor cycles-per-instruction (CPIs) get smaller, the time spent in handling translation lookaside buffer (TLB) misses could become a performance bottleneck. We explore relieving this bottleneck by (a) increasing the page size and (b) supporting two page sizes. We discuss how to build a TLB to support two page sizes and examine both alternatives experimentally with a dozen uniprogrammed, user-mode traces for the SPARC architecture. Our results show that increasing the page size to 32KB causes both a significant increase in average working set size (e.g., 60%) and a significant reduction in the TLB's contribution to CPI, CPI TLB , (namely a factor of eight) compared to using 4KB pages. Results for using two page sizes, 4KB and 32KB pages, on the other hand, show a small increase in working set size (about 10%) and variable decrease in CPI TLB , (from negligible to as good as found with the 32KB page size). CPI TLB when using two page sizes is consistently better for fully associative TLBs than for set-associative ones. Our results are preliminary, however, since (a) our traces do not include multiprogramming or operating system behavior, and (b) our page-size assignment policy may not reflect a real operating system's policy.

SPAM: a microcode based tool for tracing operating sytsem events

We have developed a tool called SPAM ( for System Performance Analysis using Microcode), based on microcode modifications to a VAX 8600, that traces operating system events as a side-effect to normal execution. This trace of interrupts, exceptions, system calls and context switches can then be processed to analyze operating system behavior for the purpose of debugging, tuning or development. SPAM allows measurement to be made on a fully operating UNIX system with little perturbation (typically less than 10%) and without the need for modifying the kernel.

Performance monitoring in a time-sharing system

A software measurement facility which is part of a general purpose time-sharing system is described. The Data Collection Facility (DCF) has been implemented in the Michigan Terminal System (MTS) for the System/360 model 67. It exists for the purpose of monitoring operating system and user program behavior and performance. The overall structure of MTS is outlined in order to explain the implementation of the DCF. Events in the system are identified and recorded from within the supervisor, and dumped to magnetic tape by an auxiliary program for off-line processing. Events in user programs which are unrelated to system actions are recorded with a supervisor call. The time of occurrence of each event is accurately recorded, and data items are further identified by job and type. The overhead associated with data collection and its interference with normal jobs is carefully analyzed, and both are shown to be minimal. Several examples are given of information obtained with the facility and of applications in which it has been useful. Some general guidelines are offered for the construction of future monitoring programs.