The Case for UBUNTU Linux Operating System Performance and Usability for Use in Higher Education in a Virtualized Environment

The use of Linux based Operating Systems (OS) in the classroom is increasing, but there is little research to address usability differences between Windows and Linux based OSs. Moreover, studies related to the ability for students to navigate effectively between Ubuntu 14.04 Long Term Support (LTS) and Windows 8 OSs are scant. This research aims to bridge the gap between modern Linux and Windows Oss, as the former represents a viable alternative to eliminate licensing costs for educational institutions. Preliminary findings, based on the analysis of the System Usability Scale results from a sample of 14 students, demonstrated that Ubuntu users did not require technical support to use the system, while the majority found little inconsistency in the system and regarded it as well integrated

Efficient Packet Processing in User-Level Operating Systems: A Study of UML

International audienceNetwork server consolidation has become popular through recent virtualization technology that builds secure, isolated network systems on shared hardware. One of the virtualization techniques used is that of User-level Operating Systems. (ULOSes) However, the isolation and security they bring comes at the price of performance, as virtualization introduces a number of overheads into the system. Such overheads can be surprisingly large, especially for complex OS modules like network protocol stacks. Our studies of the TCP/IP stack in User-mode Linux (UML), an implementation of a ULOS, attribute the resulting slow-downs to three main sources: the execution of privileged code, memory management across layers, and additional instructions to execute. To mitigate these bottlenecks, we present five optimization techniques, improving the network performance significantly, reducing packet processing latency by 60% and increasing network throughput by three folds. Furthermore, the network throughput of the improved ULOS is comparable to that of native Linux up to gigabit speeds

Accounting Per-VM Resource Usage for I/O Activities in Virtualized Environment

Computer EngineeringVirtualization technology in Cloud computing environment offers efficient resource and power utilization through enabling multiple operating system instances to run concurrently within virtual machines on a single physical machine. Virtualization layers provide the billing system of clouds for business purpose. Current cloud computing systems focus processor utilization or number of virtual machines allocated by each user for billing. However, the billing system based on processor utilization may be unfair when several virtual machines that run on single physical machine have different workloads respectively. To improve fairness of billing and resource provisioning, the system has to consider about not only processer but also I/O resource utilization. The Xen virtual machine monitor follows a split device driver model to handle I/O requests from guest domains. Virtualized system has a driver domain, which performs I/O operations on behalf of guest domains and uses their native device to access I/O device directly. For this reason, the driver domain executes delegated instructions to processing I/O activities from guest domains. But the delegated instructions are not considered for scheduling domains or accounting. This paper presents the profiling technique of delegated processor usage to the driver domain for I/O operations per virtual machine in virtualized environment by Xen. And we introduce relationship between network utilization of guest domains and delegated processor utilization.ope

Differential virtualization for large-scale system modeling

Today’s computer networks become more complex than ever with a vast number of connected host systems running a variety of different operating systems and services. Academia and industry alike realize that education in managing such complex systems is extremely important for computer professionals because, with computers, there are many levels of detailed configuration. Configuration points can occur during all facets of computer systems including system design, implementation, and maintenance stages. In order to explore various hypotheses regarding configurations, system modeling is employed – computer professionals and researchers build test environments. Modeling environments require observable systems that are easily configurable at an accelerated rate. Observation abilities increase through re-use and preservation of models. Historical modeling solutions do not efficiently utilize computing resources and require high preservation or restoration cost as the number of modeled systems increases. This research compares a workstation-oriented, virtualization modeling solution using system differences to a workstation-oriented, imaging modeling solution using full system states. The solutions are compared based on computing resource utilization and administrative cost with respect to the number of modeled systems. Our experiments have shown that upon increasing the number of models from 30 to 60, the imaging solution requires an additional 75 minutes; whereas, the difference-based virtualization solution requires an additional three (3) minutes. The imaging solution requires 151 minutes to prepare 60 models, while the difference-based, virtualization solution requires 7 minutes to prepare 60 models. Therefore, the cost for model archival and restoration in the difference-based virtualization modeling solution is lower than that in the full system imaging-based modeling solution. In addition, by using a virtualization solution, multiple systems can be modeled on a single workstation, thus increasing workstation resource utilization. Since virtualization abstracts hardware, virtualized models are less dependent on physical hardware. Thus, by lowering hardware dependency, a virtualized model is further re-usable than a traditional system image. If an organization must perform system modeling and the organization has sufficient workstation resources, using a differential virtualization approach will decrease the time required for model preservation, increase resource utilization, and therefore provide an efficient, scalable, and modular modeling solution

Flexible multi-layer virtual machine design for virtual laboratory in distributed systems and grids.

We propose a flexible Multi-layer Virtual Machine (MVM) design intended to improve efficiencies in distributed and grid computing and to overcome the known current problems that exist within traditional virtual machine architectures and those used in distributed and grid systems. This thesis presents a novel approach to building a virtual laboratory to support e-science by adapting MVMs within the distributed systems and grids, thereby providing enhanced flexibility and reconfigurability by raising the level of abstraction. The MVM consists of three layers. They are OS-level VM, queue VMs, and components VMs. The group of MVMs provides the virtualized resources, virtualized networks, and reconfigurable components layer for virtual laboratories. We demonstrate how our reconfigurable virtual machine can allow software designers and developers to reuse parallel communication patterns. In our framework, the virtual machines can be created on-demand and their applications can be distributed at the source-code level, compiled and instantiated in runtime. (Abstract shortened by UMI.) Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis2005 .K56. Source: Masters Abstracts International, Volume: 44-03, page: 1405. Thesis (M.Sc.)--University of Windsor (Canada), 2005

Suorituskyvyn turvaaminen virtualisoidussa ympäristössä

Palvelintenlaitteistojen tehokkaampi hyödyntäminen on yksi tärkeimmistä syistä miksi viimeisten vuosien aikana julkisuudessa on puhuttu paljon virtualisoinnista ja virtuaalikoneista. Virtualisointi tehdään lisäämällä palvelimelle laitteiston ja käyttöjärjestelmän väliin kerros joka mahdollistaa usean käyttöjärjestelmän ajamisen samanaikaisesti toisistaan tietämättä. Tutkielmassa perehdytään virtuaalikoneen määritelmään, virtualisoinnin historiaan, haasteisiin ja käyttökohteisiin. Usein virtualisointia harkittaessa pohditaan säilyykö sovelluksen suorituskyky uudessa ympäristössä. Tutkielmassa myös selvitetään miten paljon virtualisointi vaikuttaa sovelluksen suorituskykyyn ja millaista suorituskykyä voidaan todellisuudessa odottaa kun monta virtuaalikonetta jakaa saman fyysisen laitteen resurssit. Tutkimuksessa selvisi, että virtualisoinnilla on selkeästi havaittava vaikutus suorituskykyyn, joka tulee ottaa huomioon virtualisointialustan laitevalinnoissa. Selvisi myös että kun yksi virtuaalikone yrittää kuluttaa kaikki jaetut resurssit kykenee virtualisointialusta turvaamaan muiden virtuaalikoneiden suorituskyvyn. Sen sijaan ääritilanteessa, jossa useampi virtuaalikone yrittää samanaikaisesti käyttää kaikki resurssit, vaatii suorituskyvyn säilyttäminen etukäteen määriteltyä virtuaalikoneiden priorisointia