Competing communities of users and developers of computer software: competition between open source software and commercial software

The open source movement is a group of volunteer programmers that has recently caused quite a stir in the software market. The volunteers of this group develop computer operating systems, programming languages, and other software. They work together in teams that communicate via the Internet. Their goal is to develop useful software that is available for free and that users can change at will. To enable users to change and improve the software, they distribute their software not only in compiled form (that a computer needs to actually run the software), but also in its source code (the lines of code that programmers write). This cooperation breaks through the usual barriers that separate corporate suppliers from their buyers. This may represent the first example where the Internet enables cooperation on a scale that changes market dynamics. This paper studies the interaction between the network dynamics of the open source movement and the dynamics of a commercial software supplier. It makes our first step in identifying conditions that support a successful development of open source software. We focus on one particular set of projects within the open source movement, namely the Linux computer operating system.management and organization theory ;

Enhancing MINIX 3.X input/output performance

MINIX 3.X is an open-source operating system designed to be highly reliable, flexible, and secure. The kernel is extremely small and user processes, specialized servers and device driver runs as user-mode insulated processes. These features, the tiny amount of kernel code, and other aspects greatly enhance system reliability. The drawbacks of running device drivers in user-mode are the performance penalties on input/output ports access, kernel data structures access, interrupt indirect management, memory copy operations, etc.. As MINIX 3.X is based on the message transfer paradigm, device drivers must request those operations to the System Task (a special kernel representative process) sending request messages and waiting for reply messages increasing the system overhead. This article proposes a direct call mechanism that keeps system reliability running device drivers in user-mode but avoiding the message transfer, queuing, dequeuing and scheduling overheadWorkshop de Arquitecturas, Redes y Sistemas Operativos (WARSO)Red de Universidades con Carreras en Informática (RedUNCI

Enhancing MINIX 3 Input/Output performance using a virtual machine approach

MINIX 3 is an open-source operating system designed to be highly reliable, flexible, and secure. The kernel is extremely small and user processes, specialized servers and device drivers run as user-mode insulated processes. These features, the tiny amount of kernel code, and other aspects greatly enhance system reliability. The drawbacks of running device drivers in usermode are the performance penalties on input/output ports access, kernel data structures access, interrupt indirect management, memory copy operations, etc. As MINIX 3 is based on the message transfer paradigm, device drivers must request those operations to the System Task (a special kernel representative process) sending request messages and waiting for reply messages increasing the system overhead. This article proposes a direct call mechanism using a Virtual Machine (VM) approach that keeps system reliability running device drivers in user-mode but avoiding the message transfer, queuing, de-queuing and scheduling overhead.Presentado en el V Workshop Arquitectura, Redes y Sistemas Operativos (WARSO)Red de Universidades con Carreras en Informática (RedUNCI

A file server for the DistriX prototype : a multitransputer UNIX system

Bibliography: pages 90-94.The DISTRIX operating system is a multiprocessor distributed operating system based on UNIX. It consists of a number of satellite processors connected to central servers. The system is derived from the MINIX operating system, compatible with UNIX Version 7. A remote procedure call interface is used in conjunction with a system wide, end-to-end communication protocol that connects satellite processors to the central servers. A cached file server provides access to all files and devices at the UNIX system call level. The design of the file server is discussed in depth and the performance evaluated. Additional information is given about the software and hardware used during the development of the project. The MINIX operating system has proved to be a good choice as the software base, but certain features have proved to be poorer. The Inmos transputer emerges as a processor with many useful features that eased the implementation

Articulating the speed(s) of the Internet: the case of open source/free software

"The Internet is widely considered as a key factor of speeding up social and cultural change. It represents the merging of information and communication technologies and enables flows of information and capital, and communication and co-operation regardless of space and, possibly, time. The paper explores the example of Open Source/Free Software development, i.e. software development in self-organised projects based on a considerable share of voluntary work. Here, we find complex articulations of speeding up and slowing down technological development. Open Source/Free Software projects complement the logic of speeding up technological progress and of obsolescence with a reflexive logic of optionality, variety and sustainability which addresses the accessibility of technology and knowledge as a precondition for future creativity beyond markets and organisations." (author's abstract

Towards a Flexible, Lightweight Virtualization Alternative

In recent times, two virtualization approaches have become dominant: hardware-level and operating system-level virtualization. They differ by where they draw the virtualization boundary between the virtualizing and the virtualized part of the system, resulting in vastly different properties. We argue that these two approaches are extremes in a continuum, and that boundaries in between the extremes may combine several good properties of both. We propose abstractions to make up one such new virtualization boundary, which combines hardware-level flexibility with OS-level resource sharing. We implement and evaluate a first prototype

A comprehensive lightweight inter-domain procedure call mechanism for concurrent computations

Many inter-domain procedure calls (IDPCs) have been developed to provide fast communication services between protection domains. Different techniques have been employed to trade protection for performance. However, few studies have been made to discuss issues for constructing a comprehensive and generally usable IDPC facility. In this paper, we evaluate the tradeoff between protection and performance in a IDPC facility, and introduce a new IDPC mechanism which shows its merits by achieving comprehensiveness with secure protection and a performance that is comparable with some well-known mechanisms.published_or_final_versio

Enhancing MINIX 3 input/output performance using a virtual machine approach

MINIX 3 is an open-source operating system designed to be highly reliable, flexible, and secure. The kernel is extremely small and user processes, specialized servers and device drivers run as user-mode insulated processes. These features, the tiny amount of kernel code, and other aspects greatly enhance system reliability. The drawbacks of running device drivers in usermode are the performance penalties on input/output ports access, kernel data structures access, interrupt indirect management, memory copy operations, etc. As MINIX 3 is based on the message transfer paradigm, device drivers must request those operations to the System Task (a kernel representative process) sending request messages and waiting for reply messages increasing the system overhead. This article proposes a direct call mechanism using a Virtual Machine (VM) approach that keeps system reliability running device drivers in user-mode but avoiding the message transfer, queuing, de-queuing and scheduling overhead.Sociedad Argentina de Informática e Investigación Operativ

Enhancing MINIX 3.X input/output performance

MINIX 3.X is an open-source operating system designed to be highly reliable, flexible, and secure. The kernel is extremely small and user processes, specialized servers and device driver runs as user-mode insulated processes. These features, the tiny amount of kernel code, and other aspects greatly enhance system reliability. The drawbacks of running device drivers in user-mode are the performance penalties on input/output ports access, kernel data structures access, interrupt indirect management, memory copy operations, etc.. As MINIX 3.X is based on the message transfer paradigm, device drivers must request those operations to the System Task (a special kernel representative process) sending request messages and waiting for reply messages increasing the system overhead. This article proposes a direct call mechanism that keeps system reliability running device drivers in user-mode but avoiding the message transfer, queuing, dequeuing and scheduling overheadWorkshop de Arquitecturas, Redes y Sistemas Operativos (WARSO)Red de Universidades con Carreras en Informática (RedUNCI