The Linux Operating System
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RCU Usage in the Linux Kernel: One Decade Later
RCU Usage In the Linux Kernel: One Decade Later Paul E. McKenney Silas Boyd-Wickizer Jonathan Walpole Linux Technology Center MIT CSAIL Computer Science Department IBM Beaverton Portland State University Abstract unique among the commonly used kernels. Understand- ing RCU is now a prerequisite for understanding the Linux Read-copy update (RCU) is a scalable high-performance implementation and its performance. synchronization mechanism implemented in the Linux The success of RCU is, in part, due to its high perfor- kernel. RCU’s novel properties include support for con- mance in the presence of concurrent readers and updaters. current reading and writing, and highly optimized inter- The RCU API facilitates this with two relatively simple CPU synchronization. Since RCU’s introduction into the primitives: readers access data structures within RCU Linux kernel over a decade ago its usage has continued to read-side critical sections, while updaters use RCU syn- expand. Today, most kernel subsystems use RCU. This chronization to wait for all pre-existing RCU read-side paper discusses the requirements that drove the devel- critical sections to complete. When combined, these prim- opment of RCU, the design and API of the Linux RCU itives allow threads to concurrently read data structures, implementation, and how kernel developers apply RCU. even while other threads are updating them. This paper describes the performance requirements that 1 Introduction led to the development of RCU, gives an overview of the RCU API and implementation, and examines how ker- The first Linux kernel to include multiprocessor support nel developers have used RCU to optimize kernel perfor- is not quite 20 years old. -
Dell Inspiron 7391 Setup and Specifications
Inspiron 7391 2n1 Setup and Specifications Regulatory Model: P113G Regulatory Type: P113G001 Notes, cautions, and warnings NOTE: A NOTE indicates important information that helps you make better use of your product. CAUTION: A CAUTION indicates either potential damage to hardware or loss of data and tells you how to avoid the problem. WARNING: A WARNING indicates a potential for property damage, personal injury, or death. © 2018 - 2019 Dell Inc. or its subsidiaries. All rights reserved. Dell, EMC, and other trademarks are trademarks of Dell Inc. or its subsidiaries. Other trademarks may be trademarks of their respective owners. 2019 - 07 Rev. A00 Contents 1 Set up your Inspiron 7391 2n1.........................................................................................................4 2 Views of Inspiron 7391 2n1............................................................................................................ 6 Right........................................................................................................................................................................................6 Left.......................................................................................................................................................................................... 6 Base......................................................................................................................................................................................... 7 Display.................................................................................................................................................................................... -
BEA TUXEDO Reference Manual Section 5 - File Formats and Data Descriptions
BEA TUXEDO Reference Manual Section 5 - File Formats and Data Descriptions BEA TUXEDO Release 6.5 Document Edition 6.5 February 1999 Copyright Copyright © 1999 BEA Systems, Inc. All Rights Reserved. Restricted Rights Legend This software and documentation is subject to and made available only pursuant to the terms of the BEA Systems License Agreement and may be used or copied only in accordance with the terms of that agreement. It is against the law to copy the software except as specifically allowed in the agreement. This document may not, in whole or in part, be copied photocopied, reproduced, translated, or reduced to any electronic medium or machine readable form without prior consent, in writing, from BEA Systems, Inc. Use, duplication or disclosure by the U.S. Government is subject to restrictions set forth in the BEA Systems License Agreement and in subparagraph (c)(1) of the Commercial Computer Software-Restricted Rights Clause at FAR 52.227-19; subparagraph (c)(1)(ii) of the Rights in Technical Data and Computer Software clause at DFARS 252.227-7013, subparagraph (d) of the Commercial Computer Software--Licensing clause at NASA FAR supplement 16-52.227-86; or their equivalent. Information in this document is subject to change without notice and does not represent a commitment on the part of BEA Systems. THE SOFTWARE AND DOCUMENTATION ARE PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND INCLUDING WITHOUT LIMITATION, ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. FURTHER, BEA Systems DOES NOT WARRANT, GUARANTEE, OR MAKE ANY REPRESENTATIONS REGARDING THE USE, OR THE RESULTS OF THE USE, OF THE SOFTWARE OR WRITTEN MATERIAL IN TERMS OF CORRECTNESS, ACCURACY, RELIABILITY, OR OTHERWISE. -
INT 09H (9) Keyboard
INT 09h (9) Keyboard The keyboard generates an INT 9 every time a key is pushed or released. Notes: This is a hardware interrupt (IRQ 1) activated by the make or break of every keystroke. The default INT 9 handler in the ROM reads the make and break scan codes from the keyboard and converts them into actions or key codes as follows: ş For ASCII keys, when a make code is encountered, the ASCII code and the scan code for the key are placed in the 32-byte keyboard buffer, which is located at 0:41Eh. The ASCII code and scan code are placed in the buffer at the location addressed by the Keyboard Buffer Tail Pointer (0:041Ch). The Keyboard Buffer Tail Pointer is then incremented by 2, and if it points past the end of the buffer, it is adjusted so that it points to the beginning of the buffer. ş If Ctrl, Alt, or Shift has been pressed, the Shift Status (0:0417h) and Extended Shift Status (0:0418h) bytes are updated. ş If the Ctrl-Alt-Del combination has been pressed, the Reset Flag (0:0472h) is set to 1234h and control is given to the power-on self test (POST). Because the Reset Flag is 1234h, the POST routine bypasses the memory test. ş If the Pause key sequence has been entered, this interrupt enters an indefinite loop. The loop is broken as soon as a valid ASCII keystroke is entered. (The PC Convertible issues an INT 15h, Service 41h (Wait on External Event), to execute its pause loop.) ş If the Print Screen key sequence is entered, an INT 05h (Print Screen) is executed. -
Networking Telnet
IBM i Version 7.2 Networking Telnet IBM Note Before using this information and the product it supports, read the information in “Notices” on page 99. This edition applies to IBM i 7.2 (product number 5770-SS1) and to all subsequent releases and modifications until otherwise indicated in new editions. This version does not run on all reduced instruction set computer (RISC) models nor does it run on CISC models. This document may contain references to Licensed Internal Code. Licensed Internal Code is Machine Code and is licensed to you under the terms of the IBM License Agreement for Machine Code. © Copyright International Business Machines Corporation 1998, 2013. US Government Users Restricted Rights – Use, duplication or disclosure restricted by GSA ADP Schedule Contract with IBM Corp. Contents Telnet................................................................................................................... 1 What's new for IBM i 7.2..............................................................................................................................1 PDF file for Telnet........................................................................................................................................ 1 Telnet scenarios...........................................................................................................................................2 Telnet scenario: Telnet server configuration.........................................................................................2 Telnet scenario: Cascaded Telnet -
LMAX Disruptor
Disruptor: High performance alternative to bounded queues for exchanging data between concurrent threads Martin Thompson Dave Farley Michael Barker Patricia Gee Andrew Stewart May-2011 http://code.google.com/p/disruptor/ 1 Abstract LMAX was established to create a very high performance financial exchange. As part of our work to accomplish this goal we have evaluated several approaches to the design of such a system, but as we began to measure these we ran into some fundamental limits with conventional approaches. Many applications depend on queues to exchange data between processing stages. Our performance testing showed that the latency costs, when using queues in this way, were in the same order of magnitude as the cost of IO operations to disk (RAID or SSD based disk system) – dramatically slow. If there are multiple queues in an end-to-end operation, this will add hundreds of microseconds to the overall latency. There is clearly room for optimisation. Further investigation and a focus on the computer science made us realise that the conflation of concerns inherent in conventional approaches, (e.g. queues and processing nodes) leads to contention in multi-threaded implementations, suggesting that there may be a better approach. Thinking about how modern CPUs work, something we like to call “mechanical sympathy”, using good design practices with a strong focus on teasing apart the concerns, we came up with a data structure and a pattern of use that we have called the Disruptor. Testing has shown that the mean latency using the Disruptor for a three-stage pipeline is 3 orders of magnitude lower than an equivalent queue-based approach. -
A Thread Synchronization Model for the PREEMPT RT Linux Kernel
A Thread Synchronization Model for the PREEMPT RT Linux Kernel Daniel B. de Oliveiraa,b,c, R^omulo S. de Oliveirab, Tommaso Cucinottac aRHEL Platform/Real-time Team, Red Hat, Inc., Pisa, Italy. bDepartment of Systems Automation, UFSC, Florian´opolis, Brazil. cRETIS Lab, Scuola Superiore Sant'Anna, Pisa, Italy. Abstract This article proposes an automata-based model for describing and validating sequences of kernel events in Linux PREEMPT RT and how they influence the timeline of threads' execu- tion, comprising preemption control, interrupt handling and control, scheduling and locking. This article also presents an extension of the Linux tracing framework that enables the trac- ing of kernel events to verify the consistency of the kernel execution compared to the event sequences that are legal according to the formal model. This enables cross-checking of a kernel behavior against the formalized one, and in case of inconsistency, it pinpoints possible areas of improvement of the kernel, useful for regression testing. Indeed, we describe in details three problems in the kernel revealed by using the proposed technique, along with a short summary on how we reported and proposed fixes to the Linux kernel community. As an example of the usage of the model, the analysis of the events involved in the activation of the highest priority thread is presented, describing the delays occurred in this operation in the same granularity used by kernel developers. This illustrates how it is possible to take advantage of the model for analyzing the preemption model of Linux. Keywords: Real-time computing, Operating systems, Linux kernel, Automata, Software verification, Synchronization. -
Security in Ordinary Operating Systems
39 C H A P T E R 4 Security in Ordinary Operating Systems In considering the requirements of a secure operating system,it is worth considering how far ordinary operating systems are from achieving these requirements. In this chapter, we examine the UNIX and Windows operating systems and show why they are fundamentally not secure operating systems. We first examine the history these systems, briefly describe their protection systems, then we show, using the requirements of a secure operating system defined in Chapter 2, why ordinary operating systems are inherently insecure. Finally, we examine common vulnerabilities in these systems to show the need for secure operating systems and the types of threats that they will have to overcome. 4.1 SYSTEM HISTORIES 4.1.1 UNIX HISTORY UNIX is a multiuser operating system developed by Dennis Ritchie and Ken Thompson at AT&T Bell Labs [266]. UNIX started as a small project to build an operating system to play a game on an available PDP-7 computer. However, UNIX grew over the next 10 to 15 years into a system with considerable mindshare, such that a variety of commercial UNIX efforts were launched. The lack of coherence in these efforts may have limited the market penetration of UNIX, but many vendors, even Microsoft, had their own versions. UNIX remains a significant operating system today, embodied in many systems, such as Linux, Sun Solaris, IBM AIX, the various BSD systems, etc. Recall from Chapter 3 that Bell Labs was a member of the Multics consortium. However, Bell Labs dropped out of the Multics project in 1969, primarily due to delays in the project. -
AXEL Platine Terminal Ethernet TCP/IP Models
AXEL Platine Terminal Ethernet TCP/IP Models User's Guide May 1997 - Ref.: TCPUE105/701-2 The reproduction or the translation of this material, in part or whole, is strictly prohibited. For additional information, please contact: AXEL Zone d'activité d'Orsay-Courtabœuf 16 Avenue du Québec BP 728 91962 LES ULIS Cedex France Tel.: (33) 1 69 28 27 27 Fax: (33) 1 69 28 82 04 The information in this document is subject to change without notice. AXEL assumes no responsibility for any errors that may appear in this document. All trademarks and registered trademarks are the property of their respective holders. © - 1995-1997 - AXEL - All Rights Reserved. 1 - TCP/IP SET-UP ..........................................................................................1 2 - TERMINAL SET-UP ...................................................................................4 2.1 - GENERAL FEATURES.........................................................................5 2.1.1 - Enter Terminal Set-Up Mode ..........................................................5 2.1.2 - Set-Up Screens ..............................................................................6 2.1.3 - Predefined Set-Up..........................................................................6 2.1.4 - Local and Global Parameters .........................................................6 2.1.5 - Exit Set-Up.....................................................................................7 2.2 - SCREEN...............................................................................................8 -
Review Der Linux Kernel Sourcen Von 4.9 Auf 4.10
Review der Linux Kernel Sourcen von 4.9 auf 4.10 Reviewed by: Tested by: stecan stecan Period of Review: Period of Test: From: Thursday, 11 January 2018 07:26:18 o'clock +01: From: Thursday, 11 January 2018 07:26:18 o'clock +01: To: Thursday, 11 January 2018 07:44:27 o'clock +01: To: Thursday, 11 January 2018 07:44:27 o'clock +01: Report automatically generated with: LxrDifferenceTable, V0.9.2.548 Provided by: Certified by: Approved by: Account: stecan Name / Department: Date: Friday, 4 May 2018 13:43:07 o'clock CEST Signature: Review_4.10_0_to_1000.pdf Page 1 of 793 May 04, 2018 Review der Linux Kernel Sourcen von 4.9 auf 4.10 Line Link NR. Descriptions 1 .mailmap#0140 Repo: 9ebf73b275f0 Stephen Tue Jan 10 16:57:57 2017 -0800 Description: mailmap: add codeaurora.org names for nameless email commits ----------- Some codeaurora.org emails have crept in but the names don't exist for them. Add the names for the emails so git can match everyone up. Link: http://lkml.kernel.org/r/[email protected] 2 .mailmap#0154 3 .mailmap#0160 4 CREDITS#2481 Repo: 0c59d28121b9 Arnaldo Mon Feb 13 14:15:44 2017 -0300 Description: MAINTAINERS: Remove old e-mail address ----------- The ghostprotocols.net domain is not working, remove it from CREDITS and MAINTAINERS, and change the status to "Odd fixes", and since I haven't been maintaining those, remove my address from there. CREDITS: Remove outdated address information ----------- This address hasn't been accurate for several years now. -
Linux Foundation Collaboration Summit 2010
Linux Foundation Collaboration Summit 2010 LTTng, State of the Union Presentation at: http://www.efficios.com/lfcs2010 E-mail: [email protected] Mathieu Desnoyers April 15th, 2010 1 > Presenter ● Mathieu Desnoyers ● EfficiOS Inc. ● http://www.efficios.com ● Author/Maintainer of ● LTTng, LTTV, Userspace RCU ● Ph.D. in computer engineering ● Low-Impact Operating System Tracing Mathieu Desnoyers April 15th, 2010 2 > Plan ● Current state of LTTng ● State of kernel tracing in Linux ● User requirements ● Vertical vs Horizontal integration ● LTTng roadmap for 2010 ● Conclusion Mathieu Desnoyers April 15th, 2010 3 > Current status of LTTng ● LTTng dual-licensing: GPLv2/LGPLv2.1 ● UST user-space tracer – Userspace RCU (LGPLv2.1) ● Eclipse Linux Tools Project LTTng Integration ● User-space static tracepoint integration with gdb ● LTTng kernel tracer – maintainance-mode in 2009 (finished my Ph.D.) – active development restarting in 2010 Mathieu Desnoyers April 15th, 2010 4 > LTTng dual-licensing GPLv2/LGPLv2.1 ● LGPLv2.1 license is required to share code with user-space tracer library. ● License chosen to allow tracing of non-GPL applications. ● Headers are licensed under BSD: – Demonstrates that these headers can be included in non-GPL code. ● Applies to: – LTTng, Tracepoints, Kernel Markers, Immediate Values Mathieu Desnoyers April 15th, 2010 5 > User-space Tracing (UST) (1) ● LTTng port to user-space ● Re-uses Tracepoints and LTTng ring buffer ● Uses Userspace RCU for control synchronization ● Shared memory map with consumer daemon ● Per-process per-cpu ring buffers Mathieu Desnoyers April 15th, 2010 6 > User-space Tracing (UST) (2) ● The road ahead – Userspace trace clock for more architectures ● Some require Linux kernel vDSO support for trace clock – Utrace ● Provide information about thread creation, exec(), etc.. -
The Gold Standard for Patent Brokerage™
The Gold Standard for Patent Brokerage™ A proven record of success with more than 2500 patents sold. Executive Summary for the Sale of Enterprise Malware Removal & Restoration patent portfolio by Google 29 Assets Total · Full Patent Brokerage · Strategic IP Advisory EXECUTIVE SUMMARY FOR THE SALE OF Enterprise Malware Removal & Restoration Solutions By GOOGLE 29 TOTAL ASSETS EXECUTIVE SUMMARY FOR THE SALE OF Enterprise Malware Removal & Restoration Solutions 12 Families, 13 US Patents & their 16 family members in 8 other Jurisdictions Priority Issue Expiry Bwd/ Fwd Patent Number Patent Title Date Date Date Citations FAMILY 1 Discrete, background determination of the adequacy of Aug 19, Jun 8, Aug 18, US 6748544 10/41 security features of a computer system 1999 2004 2019 FAMILY 2 US 7114184 Oct 27, (This patent has been System and method for restoring computer systems damaged Mar 30, Sep 26, mapped against 2022 15/85 by a malicious computer program 2001 2006 representative (PTA 576) industry offerings) System and method for restoring computer systems damaged Mar 30, Aug 23, EP1374017 by a malicious computer program 2001 2006 System and method for restoring a computer system which has Mar 30, Jul 26, DE60214147 been damaged by a malicious computer program 2001 2007 System and method for restoring a computer system which as Mar 30, ZA 200306411 been damaged by a malicious computer program 2001 System And Method For Restoring Computer Systems Mar 30, Dec 3, IL157542 Damaged By A Malicious Computer Program 2001 2007 System And Method For Restoring Computer Systems Mar 30, IL157542D0 Damaged By A Malicious Computer Program 2001 FAMILY 3 Oct 26, Method and apparatus for multicast delivery of program Aug 25, Jan 4, US 7865723 2028(PTA1 6/17 information 2004 2011 172) Method and apparatus for multicast transmission of program Aug 25, Jan 26, DE102005039361 2/0 information 2004 2017 FAMILY 4 Sep 30, Sep 11, Sep 19, US 8266684 Tokenized resource access 18/35 2008 2012 2030 © 2018 Tangible IP, LLC.