Network Analysis and Business: Why Bcg Cares
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Filesystem Hierarchy Standard
Filesystem Hierarchy Standard LSB Workgroup, The Linux Foundation Filesystem Hierarchy Standard LSB Workgroup, The Linux Foundation Version 3.0 Publication date March 19, 2015 Copyright © 2015 The Linux Foundation Copyright © 1994-2004 Daniel Quinlan Copyright © 2001-2004 Paul 'Rusty' Russell Copyright © 2003-2004 Christopher Yeoh Abstract This standard consists of a set of requirements and guidelines for file and directory placement under UNIX-like operating systems. The guidelines are intended to support interoperability of applications, system administration tools, development tools, and scripts as well as greater uniformity of documentation for these systems. All trademarks and copyrights are owned by their owners, unless specifically noted otherwise. Use of a term in this document should not be regarded as affecting the validity of any trademark or service mark. Permission is granted to make and distribute verbatim copies of this standard provided the copyright and this permission notice are preserved on all copies. Permission is granted to copy and distribute modified versions of this standard under the conditions for verbatim copying, provided also that the title page is labeled as modified including a reference to the original standard, provided that information on retrieving the original standard is included, and provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one. Permission is granted to copy and distribute translations of this standard into another language, under the above conditions for modified versions, except that this permission notice may be stated in a translation approved by the copyright holder. Dedication This release is dedicated to the memory of Christopher Yeoh, a long-time friend and colleague, and one of the original editors of the FHS. -
Communicating Between the Kernel and User-Space in Linux Using Netlink Sockets
SOFTWARE—PRACTICE AND EXPERIENCE Softw. Pract. Exper. 2010; 00:1–7 Prepared using speauth.cls [Version: 2002/09/23 v2.2] Communicating between the kernel and user-space in Linux using Netlink sockets Pablo Neira Ayuso∗,∗1, Rafael M. Gasca1 and Laurent Lefevre2 1 QUIVIR Research Group, Departament of Computer Languages and Systems, University of Seville, Spain. 2 RESO/LIP team, INRIA, University of Lyon, France. SUMMARY When developing Linux kernel features, it is a good practise to expose the necessary details to user-space to enable extensibility. This allows the development of new features and sophisticated configurations from user-space. Commonly, software developers have to face the task of looking for a good way to communicate between kernel and user-space in Linux. This tutorial introduces you to Netlink sockets, a flexible and extensible messaging system that provides communication between kernel and user-space. In this tutorial, we provide fundamental guidelines for practitioners who wish to develop Netlink-based interfaces. key words: kernel interfaces, netlink, linux 1. INTRODUCTION Portable open-source operating systems like Linux [1] provide a good environment to develop applications for the real-world since they can be used in very different platforms: from very small embedded devices, like smartphones and PDAs, to standalone computers and large scale clusters. Moreover, the availability of the source code also allows its study and modification, this renders Linux useful for both the industry and the academia. The core of Linux, like many modern operating systems, follows a monolithic † design for performance reasons. The main bricks that compose the operating system are implemented ∗Correspondence to: Pablo Neira Ayuso, ETS Ingenieria Informatica, Department of Computer Languages and Systems. -
Linux Kernel and Driver Development Training Slides
Linux Kernel and Driver Development Training Linux Kernel and Driver Development Training © Copyright 2004-2021, Bootlin. Creative Commons BY-SA 3.0 license. Latest update: October 9, 2021. Document updates and sources: https://bootlin.com/doc/training/linux-kernel Corrections, suggestions, contributions and translations are welcome! embedded Linux and kernel engineering Send them to [email protected] - Kernel, drivers and embedded Linux - Development, consulting, training and support - https://bootlin.com 1/470 Rights to copy © Copyright 2004-2021, Bootlin License: Creative Commons Attribution - Share Alike 3.0 https://creativecommons.org/licenses/by-sa/3.0/legalcode You are free: I to copy, distribute, display, and perform the work I to make derivative works I to make commercial use of the work Under the following conditions: I Attribution. You must give the original author credit. I Share Alike. If you alter, transform, or build upon this work, you may distribute the resulting work only under a license identical to this one. I For any reuse or distribution, you must make clear to others the license terms of this work. I Any of these conditions can be waived if you get permission from the copyright holder. Your fair use and other rights are in no way affected by the above. Document sources: https://github.com/bootlin/training-materials/ - Kernel, drivers and embedded Linux - Development, consulting, training and support - https://bootlin.com 2/470 Hyperlinks in the document There are many hyperlinks in the document I Regular hyperlinks: https://kernel.org/ I Kernel documentation links: dev-tools/kasan I Links to kernel source files and directories: drivers/input/ include/linux/fb.h I Links to the declarations, definitions and instances of kernel symbols (functions, types, data, structures): platform_get_irq() GFP_KERNEL struct file_operations - Kernel, drivers and embedded Linux - Development, consulting, training and support - https://bootlin.com 3/470 Company at a glance I Engineering company created in 2004, named ”Free Electrons” until Feb. -
SUSE Linux Enterprise Server 11 SP4 System Analysis and Tuning Guide System Analysis and Tuning Guide SUSE Linux Enterprise Server 11 SP4
SUSE Linux Enterprise Server 11 SP4 System Analysis and Tuning Guide System Analysis and Tuning Guide SUSE Linux Enterprise Server 11 SP4 Publication Date: September 24, 2021 SUSE LLC 1800 South Novell Place Provo, UT 84606 USA https://documentation.suse.com Copyright © 2006– 2021 SUSE LLC and contributors. All rights reserved. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or (at your option) version 1.3; with the Invariant Section being this copyright notice and license. A copy of the license version 1.2 is included in the section entitled “GNU Free Documentation License”. For SUSE trademarks, see http://www.suse.com/company/legal/ . All other third party trademarks are the property of their respective owners. A trademark symbol (®, ™ etc.) denotes a SUSE or Novell trademark; an asterisk (*) denotes a third party trademark. All information found in this book has been compiled with utmost attention to detail. However, this does not guarantee complete accuracy. Neither SUSE LLC, its aliates, the authors nor the translators shall be held liable for possible errors or the consequences thereof. Contents About This Guide xi 1 Available Documentation xii 2 Feedback xiv 3 Documentation Conventions xv I BASICS 1 1 General Notes on System Tuning 2 1.1 Be Sure What Problem to Solve 2 1.2 Rule Out Common Problems 3 1.3 Finding the Bottleneck 3 1.4 Step-by-step Tuning 4 II SYSTEM MONITORING 5 2 System Monitoring Utilities 6 2.1 Multi-Purpose Tools 6 vmstat 7 -
Linux 2.5 Kernel Developers Summit
conference reports This issue’s reports are on the Linux 2.5 Linux 2.5 Kernel Developers Linux development, but I certainly Kernel Developers Summit Summit thought that, in all of this time, someone would have brought this group together OUR THANKS TO THE SUMMARIZER: SAN JOSE, CALIFORNIA before. Rik Farrow, with thanks to La Monte MARCH 30-31, 2001 Yarroll and Chris Mason for sharing their Summarized by Rik Farrow Another difference appeared when the notes. first session started on Friday morning. The purpose of this workshop was to The conference room was set up with cir- provide a forum for discussion of cular tables, each with power strips for changes to be made in the 2.5 release of For additional information on the Linux laptops, and only a few attendees were Linux (a trademark of Linus Torvalds). I not using a laptop. USENIX had pro- 2.5 Kernel Developers Summit, see the assume that many people reading this vided Aeronet wireless setup via the following sites: will be familiar with Linux, and I will hotel’s T1 link, and people were busy <http://lwn.net/2001/features/KernelSummit/> attempt to explain things that might be typing and compiling. Chris Mason of unfamiliar to others. That said, the odd- <http://cgi.zdnet.com/slink?91362:12284618> OSDN noticed that Dave Miller had numbered releases, like 2.3 and now 2.5, <http://www.osdn.com/conferences/kernel/> written a utility to modulate the speed of are development releases where the the CPU fans based upon the tempera- intent is to try out new features or make ture reading from his motherboard. -
Linux Kernel 8.1 Introduction
Page 1 of 6 Linux Kernel 8.1 Introduction: The Linux kernel is a Unix-like operating system kernel used by a variety of operating systems based on it, which are usually in the form of Linux distributions. The Linux kernel is a prominent example of free and open source software. The Linux kernel is released under the GNU General Public License version 2 (GPLv2) (plus some firmware images with various non-free licenses), and is developed by contributors worldwide. Day-to-day development discussions take place on the Linux kernel mailing list. The Linux kernel was initially conceived and created in 1991 by Finnish computer science student Linus Torvalds. Linux rapidly accumulated developers and users who adapted code from other free software projects for use with the new operating system. The Linux kernel has received contributions from thousands of programmers. 8.2 History: History In April 1991, Linus Torvalds, a 21-year-old student at the University of Helsinki, Finland started working on some simple ideas for an operating system. He started with a task switcher in Intel 80386 assembly language and a terminal driver. On 25 August 1991, Torvalds posted the following to comp.os.minix, a newsgroup on Usenet: I'm doing a (free) operating system (just a hobby, won't be big and professional like gnu) for 386(486) AT clones. This has been brewing since April, and is starting to get ready. I'd like any feedback on things people like/dislike in minix, as my OS resembles it somewhat (same physical layout of the file-system (due to practical reasons) among other things). -
Red Hat Enterprise Linux for Real Time 7 Tuning Guide
Red Hat Enterprise Linux for Real Time 7 Tuning Guide Advanced tuning procedures for Red Hat Enterprise Linux for Real Time Radek Bíba David Ryan Cheryn Tan Lana Brindley Alison Young Red Hat Enterprise Linux for Real Time 7 Tuning Guide Advanced tuning procedures for Red Hat Enterprise Linux for Real Time Radek Bíba Red Hat Customer Content Services [email protected] David Ryan Red Hat Customer Content Services [email protected] Cheryn Tan Red Hat Customer Content Services Lana Brindley Red Hat Customer Content Services Alison Young Red Hat Customer Content Services Legal Notice Copyright © 2015 Red Hat, Inc. This document is licensed by Red Hat under the Creative Commons Attribution-ShareAlike 3.0 Unported License. If you distribute this document, or a modified version of it, you must provide attribution to Red Hat, Inc. and provide a link to the original. If the document is modified, all Red Hat trademarks must be removed. Red Hat, as the licensor of this document, waives the right to enforce, and agrees not to assert, Section 4d of CC-BY-SA to the fullest extent permitted by applicable law. Red Hat, Red Hat Enterprise Linux, the Shadowman logo, JBoss, MetaMatrix, Fedora, the Infinity Logo, and RHCE are trademarks of Red Hat, Inc., registered in the United States and other countries. Linux ® is the registered trademark of Linus Torvalds in the United States and other countries. Java ® is a registered trademark of Oracle and/or its affiliates. XFS ® is a trademark of Silicon Graphics International Corp. or its subsidiaries in the United States and/or other countries. -
Linux Kernel Development
Linux Kernel Development Third Edition Developer’s Library ESSENTIAL REFERENCES FOR PROGRAMMING PROFESSIONALS Developer’s Library books are designed to provide practicing programmers with unique, high-quality references and tutorials on the programming languages and technologies they use in their daily work. All books in the Developer’s Library are written by expert technology practitioners who are especially skilled at organizing and presenting information in a way that’s useful for other programmers. Key titles include some of the best, most widely acclaimed books within their topic areas: PHP & MySQL Web Development Python Essential Reference Luke Welling & Laura Thomson David Beazley ISBN 978-0-672-32916-6 ISBN-13: 978-0-672-32978-6 MySQL Programming in Objective-C 2.0 Paul DuBois Stephen G. Kochan ISBN-13: 978-0-672-32938-8 ISBN-13: 978-0-321-56615-7 Linux Kernel Development PostgreSQL Robert Love Korry Douglas ISBN-13: 978-0-672-32946-3 ISBN-13: 978-0-672-33015-5 Developer’s Library books are available at most retail and online bookstores, as well as by subscription from Safari Books Online at safari.informit.com Developer’s Library informit.com/devlibrary Linux Kernel Development Third Edition Robert Love Upper Saddle River, NJ • Boston • Indianapolis • San Francisco New York • Toronto • Montreal • London • Munich • Paris • Madrid Cape Town • Sydney • Tokyo • Singapore • Mexico City Linux Kernel Development Acquisitions Editor Third Edition Mark Taber Development Copyright © 2010 Pearson Education, Inc. Editor All rights reserved. Printed in the United States of America. This publication is protected by Michael Thurston copyright, and permission must be obtained from the publisher prior to any prohibited repro- Technical Editor duction, storage in a retrieval system, or transmission in any form or by any means, elec- Robert P. -
The GNU General Public License (GPL) Does Govern All Other Use of the Material That Constitutes the Autoconf Macro
Notice About this document The following copyright statements and licenses apply to software components that are distributed with various versions of the StorageGRID PreGRID Environment products. Your product does not necessarily use all the software components referred to below. Where required, source code is published at the following location: ftp://ftp.netapp.com/frm-ntap/opensource/ 215-10078_A0_ur001-Copyright 2015 NetApp, Inc. All rights reserved. 1 Notice Copyrights and licenses The following component is subject to the BSD 1.0 • Free BSD - 44_lite BSD 1.0 Copyright (c) 1982, 1986, 1990, 1991, 1993 The Regents of the University of California. All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: 1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. • All advertising materials mentioning features or use of this software must display the following acknowledgement: This product includes software developed by the University of California, Berkeley and its contributors. • Neither the name of the University nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission. THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. -
Fuss, Futexes and Furwocks: Fast Userlevel Locking in Linux
Fuss, Futexes and Furwocks: Fast Userlevel Locking in Linux Hubertus Franke Rusty Russell IBM Thomas J. Watson Research Center IBM Linux Technology Center [email protected] [email protected] Matthew Kirkwood [email protected] Abstract makes it now feasible to deploy even more de- manding enterprise applications such as high Fast userlevel locking is an alternative locking end databases, business intelligence software mechanism to the typically heavy weight ker- and application servers. As a result, whole en- nel approaches such as fcntl locking and Sys- terprise business suites and middleware such 2 tem V semaphores. Here, multiple processes as SAP™, Websphere™, Oracle, DB2™ , etc., communicate locking state through shared are now available for Linux. memory regions and atomic operations. Ker- For these enterprise applications to run effi- nel involvement is only necessary when there ciently on Linux, or on any other operating is contention on a lock, in order to perform system for that matter, the OS must provide queueing and scheduling functions. In this pa- the proper abstractions and services. Enter- per we discuss the issues related to user level prise applications and applications suites are locking by following the history of ideas and increasingly built as multi process / multi- the code to the current day. We present the ef- threaded applications. Multi-threaded appli- ficacy of "futexes" through benchmarks, both cations can take better advantage of SMP synthetic and through adaptations to existing hardware, while multiple processes allows for databases. We conclude by presenting the po- higher degrees of fault tolerance, i.e., a single tential future directions of the "futex" inter- process abort does not necessarily bring the en- face. -
Interaction Between the User and Kernel Space in Linux
1 Interaction Between the User and Kernel Space in Linux Kai Lüke, Technische Universität Berlin F Abstract—System calls based on context switches from user to kernel supported in POSIX as well as System V style. A very space are the established concept for interaction in operating systems. common principle for IPC are sockets, and pipes can be seen On top of them the Linux kernel offers various paradigms for commu- as their most simple case. Besides the popular IP family with nication and management of resources and tasks. The principles and TCP/UDP, the local Unix domain sockets play a big role basic workings of system calls, interrupts, virtual system calls, special for many applications, while Netlink sockets are specific purpose virtual filesystems, process signals, shared memory, pipes, Unix or IP sockets and other IPC methods like the POSIX or System V to the Linux kernel and are not often found in user space message queue and Netlink are are explained and related to each other applications due to portability to other operating systems. in their differences. Because Linux is not a puristic project but home for There have been attempts to bring the D-BUS IPC into many different concepts, only a mere overview is presented here with the kernel with a Netlink implementation, kdbus and then focus on system calls. Bus1, but this will not be covered here. Also comparative studies with other operating systems are out of scope. 1 INTRODUCTION 2 KERNEL AND USER SPACE ERNELS in the Unix family are normally not initiating K any actions with outside effects, but rely on requests The processes have virtualized access to the memory as well from user space to perform these actions. -
Community Notebook Kernel News Zack’S Kernel News
Community Notebook Kernel News Zack’s Kernel News Chronicler Zack Licensing Confusion performing source distribution, a complete An interesting little licensing escapade occurred machine-readable copy of the corresponding Brown reports on recently. Matthew Garrett noticed that CloudLi- source code, to be distributed under the the latest news, nux corporation had released their lve kernel terms of Sections 1 and 2 above on a medium driver under a new, proprietary license, whereas customarily used for software interchange.” views, dilemmas, before, it had been released under the GPL. So apparently, a written offer would be good Technically, nothing too fishy is going on here enough, and the three-week delay might be and developments because the original author of GPL’d code is still legally acceptable. within the Linux free to release that code under other licenses. But Matthew noticed that, in this particular Kernel Development kernel community. case, the driver still pretended to the kernel to Overflow be a GPL’d driver and still used kernel symbols Thomas Gleixner posed an interesting ques- By Zack Brown that were restricted to GPL-only code. tion – all the more interesting in that it was That’s a big no-no, and Matthew submitted taken so seriously. He pointed out that inter- a patch to make the kernel automatically treat est in the kernel was continuing to grow and the lve module as non-GPL, whether it said it that the number of patch submissions from was or not. But that wasn’t the end of the story individuals and corporations was growing as because licensing is a very touchy legal sub- well.