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Sistemi Operativi Real-Time Marco Cesati Lezione R13 Sistemi Operativi Real-Time – II Schema Della Lezione
Sistemi operativi real-time Marco Cesati Lezione R13 Sistemi operativi real-time – II Schema della lezione Caratteristiche comuni VxWorks LynxOS Sistemi embedded e real-time QNX eCos Windows Linux come RTOS 15 gennaio 2013 Marco Cesati Dipartimento di Ingegneria Civile e Ingegneria Informatica Università degli Studi di Roma Tor Vergata SERT’13 R13.1 Sistemi operativi Di cosa parliamo in questa lezione? real-time Marco Cesati In questa lezione descriviamo brevemente alcuni dei più diffusi sistemi operativi real-time Schema della lezione Caratteristiche comuni VxWorks LynxOS 1 Caratteristiche comuni degli RTOS QNX 2 VxWorks eCos 3 LynxOS Windows Linux come RTOS 4 QNX Neutrino 5 eCos 6 Windows Embedded CE 7 Linux come RTOS SERT’13 R13.2 Sistemi operativi Caratteristiche comuni dei principali RTOS real-time Marco Cesati Corrispondenza agli standard: generalmente le API sono proprietarie, ma gli RTOS offrono anche compatibilità (compliancy) o conformità (conformancy) allo standard Real-Time POSIX Modularità e Scalabilità: il kernel ha una dimensione Schema della lezione Caratteristiche comuni (footprint) ridotta e le sue funzionalità sono configurabili VxWorks Dimensione del codice: spesso basati su microkernel LynxOS QNX Velocità e Efficienza: basso overhead per cambi di eCos contesto, latenza delle interruzioni e primitive di Windows sincronizzazione Linux come RTOS Porzioni di codice non interrompibile: generalmente molto corte e di durata predicibile Gestione delle interruzioni “separata”: interrupt handler corto e predicibile, ISR lunga -
The Norwegian State Railway System GTL (1976) Tor Olav Steine
The Norwegian State Railway System GTL (1976) Tor Olav Steine To cite this version: Tor Olav Steine. The Norwegian State Railway System GTL (1976). 4th History of Nordic Com- puting (HiNC4), Aug 2014, Copenhagen, Denmark. pp.290-298, 10.1007/978-3-319-17145-6_30. hal-01301420 HAL Id: hal-01301420 https://hal.inria.fr/hal-01301420 Submitted on 12 Apr 2016 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Distributed under a Creative Commons Attribution| 4.0 International License The Norwegian State Railway System GTL (1976) Tor Olav Steine, with the help of former colleagues [email protected] Abstract. In 1976 the Norwegian State Railway System (NSB) planned a new system to keep track of all its freight cars. Among the duties were these: arranging trains at the shifting station in Alnabru outside Oslo, following (tracking) the trains as they moved along the tracks inside Norway, optimization of car maintenance and statistics. The system could save millions of Norwegian Crowns by better utilization of the car pool. It was named GTL for Gods Transport Ledelse (there is no Divine link; “Gods” simply means cargo in Norwegian). -
Embedded Systems - ECE) I -M.TECH I -Semester (AUTONOMOUS-R18
Presentation on Principles of Distributed Embedded Systems (Embedded Systems - ECE) I -M.TECH I -Semester (AUTONOMOUS-R18) Prepared by, Dr. S. Vinoth Associate Professor UNIT - I REAL TIME ENVIRONMENT 2 UNIT - I REAL-TIME ENVIRONMENT .Real-time computer system requirements .classification of real time systems .simplicity, global time .internal and external clock synchronization .real time model. Real time communication .temporal relations, dependability .power and energy awareness .real time communication .event triggered .rate constrained .time triggered. 3 What is an Embedded system? 4 What is a real-time system? . A real-time system is any information processing system which has to respond to externally generated input stimuli within a finite and specified period –the correctness depends not only on the logical result but also the time it was delivered –failure to respond is as bad as the wrong response! . The computer is a component in a larger engineering system => EMBEDDED COMPUTER SYSTEM 99% of all processors are for the embedded systems market 5 Terminology • Hard real-time — systems where it is absolutely imperative that responses occur within the required deadline. E.g. Flight control systems. • Soft real-time — systems where deadlines are important but which will still function correctly if deadlines are occasionally missed. E.g. Data acquisition system. • Real real-time — systems which are hard real-time and which the response times are very short. E.g. Missile guidance system. • Firm real-time — systems which are soft real-time but in which there is no benefit from late delivery of service. A single system may have all hard, soft and real real-time subsystems In reality many systems will have a cost function associated with missing each deadline. -
Answers to Exercises
Answers to Exercises A bird does not sing because he has an answer, he sings because he has a song. —Chinese Proverb Intro.1: abstemious, abstentious, adventitious, annelidous, arsenious, arterious, face- tious, sacrilegious. Intro.2: When a software house has a popular product they tend to come up with new versions. A user can update an old version to a new one, and the update usually comes as a compressed file on a floppy disk. Over time the updates get bigger and, at a certain point, an update may not fit on a single floppy. This is why good compression is important in the case of software updates. The time it takes to compress and decompress the update is unimportant since these operations are typically done just once. Recently, software makers have taken to providing updates over the Internet, but even in such cases it is important to have small files because of the download times involved. 1.1: (1) ask a question, (2) absolutely necessary, (3) advance warning, (4) boiling hot, (5) climb up, (6) close scrutiny, (7) exactly the same, (8) free gift, (9) hot water heater, (10) my personal opinion, (11) newborn baby, (12) postponed until later, (13) unexpected surprise, (14) unsolved mysteries. 1.2: A reasonable way to use them is to code the five most-common strings in the text. Because irreversible text compression is a special-purpose method, the user may know what strings are common in any particular text to be compressed. The user may specify five such strings to the encoder, and they should also be written at the start of the output stream, for the decoder’s use. -
Ir^Is*»?.'2R-£
DENSITY ADD MAGNETIC FIELD MEASUREMENTS IN THE TOHHAC IV-c PLASMA ;.ir^is*»?.'2r-£ John Halter Coonrod, Jr. ^riSSKSss-*"*! Lawrence Berkeley Laboratory Berkeley, California 94720 lO DiSTmm-narLT — -iii- TABLE OF CONTENTS ABSTRACT vii PREFACE ix 1. INTRODUCTION 1 1.1 Tormac Concept 1 1.2 Tormac IV . 5 1.3 Experimental Sequence 5 1.4 Motivation for Tormac IV-c 7 1.5 Diagnostics 9 1.5.1 Table of Typical Tormac IV-c Values . 10 1.6 Questions and Conclusions 11 1.7 References 13 2. EXPERIMENTAL DATA AND ANALYSIS 15 2.1 Data Summary 15 2.2 Overall Picture 16 2.3 Spectral Measurements 17 2.3.1 Reconstruction Technique 18 2.3.4 Problems with Reconstruction ..... 24 2.3.3 Do Profiles and Density 25 2.3.4 He 4686 Profiles and Fluctuations ... 37 2.4 Thomson Scattering 44 2.5 Magnetic Measurements 48 2.5.1 Flux Exclusion 50 2.5.2 Description of Small Probes 55 2.5.3 Small Probe Data 59 2.6 Interferometer Measurements 73 2.6.1 Description and Access 73 2.6.2 Alignment and Calibration Procedure . 77 2.6.3 Analysis Technique 78 2.6.4 Radial Density Profiles 79 2.7 Overall Particle Accounting ... 79 2.8 References 105 3. EXPERIMENT LAYOUT AND CONSTRUCTION 107 3.1 Glass Vessel 107 3.2 Cusp Winding 110 3.3 Cusp Bank and Switches 113 3.4 Bias Circuit 116 3.5 Pre-ionize Circuit 116 3.6 Heater Circuit 117 3.7 Floor Plan 118 3.8 Vacuum System 118 3.9 Safety Interlocks 122 3.10 References 123 -iv- 4. -
Lawrence Berkeley National Laboratory Lawrence Berkeley National Laboratory
Lawrence Berkeley National Laboratory Lawrence Berkeley National Laboratory Title SOFTWARE CATALOG Permalink https://escholarship.org/uc/item/7vp4q4x1 Author Beyers, Evelyn Publication Date 2013-06-27 eScholarship.org Powered by the California Digital Library University of California LBL·l 081 1 <! . UC-4 NATIONAL RESOURCE FOR COMPUTATION "--"" IN CHEMISTRY TWO-WEEK LOAN COPY This is a Library Circulating Copy wh may be borrowed for two weeks. For a retention copy, call Tech. Divisiony Ext. 6782. Vol. 1 February 1 for the U.S. Department of under Contract W-7405-ENG-48 and the National Science Foundation under Agreement CHE-7721305 DISCLAIMER This document was prepared as an account of work sponsored by the United States Govemment. While this document is believed to contain correct information, neither the United States Government nor any agency thereof, nor the Regents of the University of California, nor any of their employees, makes any wan·anty, express or implied, or assumes any legal responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by its trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Govemment or any agency thereof, or the Regents of the University of Califomia. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof or the Regents of the University of California. -
SINTRAN III NODAL Systems
THE SIHTIAN III NODAL SYSTEM Oslo University Varsion T.B. Skuli Institute of Physics University of Oslo FOB 1048, Blindern, Oslo 3, Norway Report 80-17 October 1980 The SINTRAN III NODAL System Oslo University Version T.B. Skaali Institute of Physics, University of Oslo POB 1046, Blindern, Oslo 3, Norway October 198O -ooOoo- 1. Introduction , 2. Basic Features of NODAL i 3. The NODILER Preinterpreter 2 4. Implementation under SINTRAN III 4 4.1 Background NODAL 5 4.2 Real Time NODAL Programs o 4.2.1 Interactive RT NODAL Programs 7 4.2.2 File-driven RT NODAL Programs 7 4.3 Oslo University Revisions to the NODAL System ... b 5. NODAL-SINTRAN III Fi...-i.ions 10 b.i RT Program Control 10 5.2 "Escape" Control Functions 11 5.3 General RT Functions 11 5.4 CAMAC Functions 15 5.5 Magnetic Tape and Floppy Disc Handling 16 5.6 Input/Output and I/O Buffer Functions 17 3.7 Functions for Fast Input/Output of Integers Arrays . 1C- 5.8 SINTRAN III Monitor Calls - NODAL Functions . 21 6. Functions for Double Precision Integers 22 7. Display Functions 23 6. TEKPLOT Program Package 24 References 25 Appendix: A Examples on the RT Use of NODAL 26 Throughout the report, replace the characters Æ and Å with [ and ], respectively. October 198O Introduction This report describes the Oalo University implementation of the NODAL system under the operating system 3INTRAN III. At present, the NODAL system has been installed on two NORD-'O.S computers at the Physics Department and on a NORD-'OO at the Chemistry Department, University of Oslo. -
Opensource Software Im Alltag
OpensourceOpensource SoftwareSoftware imim AlltagAlltag -- IstIst dasdas möglich?möglich? Willkommen zum Xing Stammtisch Alexander Demmler – 25.11.2016 © A. Demmler 2016 www.lacunasolutions.com 1 Marktanteile Desktop Systeme 2016 © A. Demmler 2016 www.lacunasolutions.com 2 Webserver Systeme © A. Demmler 2016 www.lacunasolutions.com 3 Einsatz von OSS in US Unternehmen: Northbridge Eine Venture Capital Company. Game changers disrupt existing markets. They also create new multi-billion dollar markets and have the potential to change the way we live and work. http://www.northbridge.com © A. Demmler 2016 www.lacunasolutions.com 4 Was bedeutet OpenSource? • OpenSource Software (OSS) ist professionelle Software unter einer alternativen Entwicklungs- und Vertriebsform • OpenSource ist nicht Linux - aber Linux ist auch OpenSource! • OpenSource bedeutet ein Stück Freiheit: - freie Auswahl - Freiheit ob und wieviel man bezahlt - Freiheit in der Nutzung © A. Demmler 2016 www.lacunasolutions.com 5 Was ist die Community? • Die Community besteht aus - Entwicklern + Beratern + Anwendern + Hobbyisten - grossen Unternehmen (HP, IBM, SUN) - Distributoren wie SUSE, RedHat, Ubuntu u.a. • Die Community entwickelt und pflegt gemeinsam die Software und bietet Unterstützung (Support) • Die Community ist kein Club von Hackern, Freaks und anderen Bösewichten! © A. Demmler 2016 www.lacunasolutions.com 6 Das Geschäftsmodell Freie Software Dienstleistungen (Kosten) Basis Version Erweiterungen Download im WWW Service + Support Online Support Schulungen Zusatzeinkünfte Werbung + Sponsoren © A. Demmler 2016 www.lacunasolutions.com 7 Lizenzrechtliches • Softwarecode (Quellen) sind offen gelegt: - Verbreitung und Nutzung sind ausdrücklich erlaubt - Veränderung (Anpassung, Erweiterung) erlaubt - Quellcode muss offengelegt werden • Es gibt historisch bedingt verschiedene Lizenzmodelle. (GPL, OSL, CPL, EPL u.a) • EU Initiative um Lizenzen vereinen: http://ec.europa.eu ACHTUNG: Auch hier gelten Vorschriften! Computerwoche: http://www.computerwoche.de © A. -
Norsk Data AS, the Fenomenon (Brief) Content
Norsk Data AS, The Fenomenon (brief) Tor Olav Steine, with the help of former colleaguesi . Abstract. Norsk Data was a remarkable company that went in just 20 years from a glimmer in the eyes of some computer enthusiasts to become number 2 in stock value at Oslo Stock Exchange. Then within a few years it collapsed, without obvious reason. How was this tremendous success possible and why did it collapse? NOTE: This history brief of the Norsk Data Company is based upon a Springer Verlag publication resulting from the HINC3 Conference in Stockholm 2010. It is ONLY for personal use, and not allowed for distribution or publishing. Content 1 The beginning ................................................................................................................................................. 2 2. The demanding customers .............................................................................................................................. 4 3 The years of fast growth ................................................................................................................................. 7 4. Crisis and downfall ......................................................................................................................................... 9 6. About the Author .......................................................................................................................................... 11 7. References ................................................................................................................................................... -
04 Pascal Newsletter July 1976
.-:'a· July 1976 PASCAL NEWSLETTER Number 4 FROM THE EDITOR The fourth newsletter is long qverdue, the third being published in February 1975. There have been many significant events that need announcing. The highlights are: Release 2 of PASCAL 6000-3.4 has beeh made available by Dr. Urs Ammann at Eiqgenossische Technische Hochschule in Zurich, Switzerland. It is also available from Mr. George Richmond at the University of Colorado Computing Center in Boulder, Colorado and Mr. Carroll Morgan at the Basser Department of Computer Science, University of Sydney, Australia. Many improvements have been made over Release 1 and future developments are promised. See page 73. Mr. Carroll Morgan of the Basser Department of Computer Science at the University of Sydney, Australia has kindly agreed to distribute ETH Pascal and portable Pascal for Australia and neighboring regions. Interested parties should contact Mr. Morgan for more informa~ion. Mr. Andy Mickel of the University of Minnesota kindly agreed to take over editorial control and publication of the Pascal Newsletter commencing wi'th issue Number 5 in September 1976. He is also organizing a User's Group. See pages 88 and 89. An improved portable Pascal has been released from ETH, , zur ich. See page 81. News of Pascal compilers for numerous machines has been received. See pages 96 and following. An expanded bibliography .of Pascal literature has. been compiled. See pages 100 and following. I have enjoyed producing the first four newsletters but I have found it to be very time consuming. I am grateful to Andy for taking over these duties with enthusiasm. -
Appendix a Information Theory
Appendix A Information Theory This appendix serves as a brief introduction to information theory, the foundation of many techniques used in data compression. The two most important terms covered here are entropy and redundancy (see also Section 2.3 for an alternative discussion of these concepts). A.1 Information Theory Concepts We intuitively know what information is. We constantly receive and send information in the form of text, sound, and images. We also feel that information is an elusive nonmathematical quantity that cannot be precisely defined, captured, or measured. The standard dictionary definitions of information are (1) knowledge derived from study, experience, or instruction; (2) knowledge of a specific event or situation; intelligence; (3) a collection of facts or data; (4) the act of informing or the condition of being informed; communication of knowledge. Imagine a person who does not know what information is. Would those definitions make it clear to them? Unlikely. The importance of information theory is that it quantifies information. It shows how to measure information, so that we can answer the question “how much information is included in this piece of data?” with a precise number! Quantifying information is based on the observation that the information content of a message is equivalent to the amount of surprise in the message. If I tell you something that you already know (for example, “you and I work here”), I haven’t given you any information. If I tell you something new (for example, “we both received a raise”), I have given you some information. If I tell you something that really surprises you (for example, “only I received a raise”), I have given you more information, regardless of the number of words I have used, and of how you feel about my information. -
08 Pascal Newsletter May 1977
PASCAL USER'S GROUP USER'S GROUP PASCALNEWSLETTER NUMBER 8 COMMUNICATIONS ABOUT THE PROGRAMMING LANGUAGE PASCAL BY PASCALERS MAY} 1977 TAB LEO F CON TEN T S # a POLICY .EDITOR'S CONTRIBUTION ..... "# # 2 HERE AND TffEREWITH PASCAL. * 2 News .'.* . 3 Conferences # 6 Books and Articles # * 7 Applications * # 8 ARTICLES * 8 "Development of a Pascal Compiler for the C. I.1. IRIS 50. A Parti al History. II # '. .. Olivier Lecarme # * * 11 "A Further Defence of Formatted Iriput" '" # # .c'.' .' " - B. A. E. 'Meeki ngs ~" 'J' ; .,* 12 ilPt6~6:~al S fo~P:~~ca 1" * # . - heorge H. Richmond # 15 "A Proposal for Increased Security in the Use of Variant * Records"- William Barabash, Charles R. Hill, and * # Richard B. Kieburtz . # * 16 "Update on UCSD Pascal, Activities" * #' - Kenneth L. Bowl es * 18 # 19 * 22 # 40 40 * 40 # 40 " 40 * 42 * # 44 / # * 64 * # 65 ALL PURPOSE COUPON "'.~SCl~L USER 'S GROUP POLl (1 ES Purposes - are to promote the use of the programming language Pascal as well as the ideas behind Pascal. Pascal is a practical, general purpose language \,/ith a small and systematic structure being used for: ' * teaching programming concepts . * developing reliable "production" software * implementing software efficiently on today's machines * writing portable software Membership - is open to anyone: particularly the Pasc~l user, teacher, maihtainer, I impl ementor, di stributor, or just pl ai nfan. Institutional membershi ps, ' especially libraries, are encouraged. Membership is per academic year end~ June 30. Anyone joining for a particular year will receivea1l 4 quarterl} issues of FMC.a£. NeLIJI.>R.e:Ue.1t for that year. {In other words, back issues ar sent automatically.} First time members receive a receipt for membership; renewers do not to save PUG postage.