Plan9 Operating System
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Venti Analysis and Memventi Implementation
Master’s thesis Venti analysis and memventi implementation Designing a trace-based simulator and implementing a venti with in-memory index Mechiel Lukkien [email protected] August 8, 2007 Committee: Faculty of EEMCS prof. dr. Sape J. Mullender DIES, Distributed and Embedded Systems ir. J. Scholten University of Twente ir. P.G. Jansen Enschede, The Netherlands 2 Abstract [The next page has a Dutch summary] Venti is a write-once content-addressed archival storage system, storing its data on magnetic disks: each data block is addressed by its 20-byte SHA-1 hash (called score). This project initially aimed to design and implement a trace-based simula- tor matching Venti behaviour closely enough to be able to use it to determine good configuration parameters (such as cache sizes), and for testing new opti- misations. A simplistic simulator has been implemented, but it does not model Venti behaviour accurately enough for its intended goal, nor is it polished enough for use. Modelled behaviour is inaccurate because the advanced optimisations of Venti have not been implemented in the simulator. However, implementation suggestions for these optimisations are presented. In the process of designing the simulator, the Venti source code has been investigated, the optimisations have been documented, and disk and Venti per- formance have been measured. This allowed for recommendations about per- formance, even without a simulator. Beside magnetic disks, also flash memory and the upcoming mems-based storage devices have been investigated for use with Venti; they may be usable in the near future, but require explicit support. The focus of this project has shifted towards designing and implementing memventi, an alternative implementation of the venti protocol. -
Java Implementation of the Graphical User Interface of the Octopus Distributed Operating System
Java implementation of the graphical user interface of the Octopus distributed operating system Submitted by Aram Sadogidis Advisor Prof. Spyros Lalis University of Thessaly Volos, Greece October 2012 Acknowledgements I am sincerely grateful for all the people that supported me during my Uni- versity studies. Special thanks to professor Spyros Lalis, my mentor, who had decisive influence in shaping my character as an engineer. Also many thanks to my family and friends, whose support all these years, encouraged me to keep moving forward. 1 Contents 1 Introduction 4 2 System software technologies 6 2.1 Inferno OS . 6 2.2 JavaSE and Android framework . 8 2.3 Synthetic file systems . 10 2.3.1 Styx . 10 2.3.2 Op . 12 3 Octopus OS 14 3.1 UpperWare architecture . 14 3.2 Omero, a filesystem based window system . 16 3.3 Olive, the Omero viewer . 19 3.4 Ox, the Octopus shell . 21 4 Java Octopus Terminal 23 4.1 JOlive . 24 4.2 Desktop version . 25 4.2.1 Omero package . 26 4.2.2 ui package . 27 4.3 Android version . 28 4.3.1 com.jolive.Omero . 28 4.3.2 com.jolive.ui . 29 4.3.3 Pull application's UI . 30 5 Future perspective 33 5.1 GPS resources . 33 5.2 JOp . 34 5.3 Authentication device . 34 5.4 Remote Voice commander . 34 5.5 Conclusion . 35 6 Thesis preview in Greek 38 2 List of Figures 2.1 An application operates on a synthetic file as if it is a disk file, effectively communicating with a synthetic file system server. -
Persistent 9P Sessions for Plan 9
Persistent 9P Sessions for Plan 9 Gorka Guardiola, [email protected] Russ Cox, [email protected] Eric Van Hensbergen, [email protected] ABSTRACT Traditionally, Plan 9 [5] runs mainly on local networks, where lost connections are rare. As a result, most programs, including the kernel, do not bother to plan for their file server connections to fail. These programs must be restarted when a connection does fail. If the kernel’s connection to the root file server fails, the machine must be rebooted. This approach suffices only because lost connections are rare. Across long distance networks, where connection failures are more common, it becomes woefully inadequate. To address this problem, we wrote a program called recover, which proxies a 9P session on behalf of a client and takes care of redialing the remote server and reestablishing con- nection state as necessary, hiding network failures from the client. This paper presents the design and implementation of recover, along with performance benchmarks on Plan 9 and on Linux. 1. Introduction Plan 9 is a distributed system developed at Bell Labs [5]. Resources in Plan 9 are presented as synthetic file systems served to clients via 9P, a simple file protocol. Unlike file protocols such as NFS, 9P is stateful: per-connection state such as which files are opened by which clients is maintained by servers. Maintaining per-connection state allows 9P to be used for resources with sophisticated access control poli- cies, such as exclusive-use lock files and chat session multiplexers. It also makes servers easier to imple- ment, since they can forget about file ids once a connection is lost. -
HTTP-FUSE Xenoppix
HTTP-FUSE Xenoppix Kuniyasu Suzaki† Toshiki Yagi† Kengo Iijima† Kenji Kitagawa†† Shuichi Tashiro††† National Institute of Advanced Industrial Science and Technology† Alpha Systems Inc.†† Information-Technology Promotion Agency, Japan††† {k.suzaki,yagi-toshiki,k-iijima}@aist.go.jp [email protected], [email protected] Abstract a CD-ROM. Furthermore it requires remaking the entire CD-ROM when a bit of data is up- dated. The other solution is a Virtual Machine We developed “HTTP-FUSE Xenoppix” which which enables us to install many OSes and ap- boots Linux, Plan9, and NetBSD on Virtual plications easily. However, that requires in- Machine Monitor “Xen” with a small bootable stalling virtual machine software. (6.5MB) CD-ROM. The bootable CD-ROM in- cludes boot loader, kernel, and miniroot only We have developed “Xenoppix” [1], which and most part of files are obtained via Internet is a combination of CD/DVD bootable Linux with network loopback device HTTP-FUSE “KNOPPIX” [2] and Virtual Machine Monitor CLOOP. It is made from cloop (Compressed “Xen” [3, 4]. Xenoppix boots Linux (KNOP- Loopback block device) and FUSE (Filesys- PIX) as Host OS and NetBSD or Plan9 as Guest tem USErspace). HTTP-FUSE CLOOP can re- OS with a bootable DVD only. KNOPPIX construct a block device from many small block is advanced in automatic device detection and files of HTTP servers. In this paper we describe driver integration. It prepares the Xen environ- the detail of the implementation and its perfor- ment and Guest OSes don’t need to worry about mance. lack of device drivers. -
Bell Labs, the Innovation Engine of Lucent
INTERNSHIPS FOR RESEARCH ENGINEERS/COMPUTER SCIENTISTS BELL LABS DUBLIN (IRELAND) – BELL LABS STUTTGART (GERMANY) Background Candidates are expected to have some experience related to the following topics: Bell Laboratories is a leading end-to-end systems and • Operating systems, virtualisation and computer solutions research lab working in the areas of cloud architectures. and distributed computing, platforms for real-time • big-data streaming and analytics, wireless networks, Software development skills (C/C++, Python). • semantic data access, services-centric operations and Computer networks and distributed systems. thermal management. The lab is embedded in the • Optimisation techniques and algorithms. great traditions of the Bell Labs systems research, in- • Probabilistic modelling of systems performance. ternationally renowned as the birthplace of modern The following skills or interests are also desirable: information theory, UNIX, the C/C++ programming • languages, Awk, Plan 9 from Bell Labs, Inferno, the Experience with OpenStack or OpenNebula or Spin formal verification tool, and many other sys- other cloud infrastructure management software. • tems, languages, and tools. Kernel-level programming (drivers, scheduler,...). • Xen, KVM and Linux scripting/administration. We offer summer internships in our Cloud • Parallel and distributed systems programming Computing team, spread across the facilities in Dublin (Ireland) and Stuttgart (Germany), focusing (MPI, OpenMP, CUDA, MapReduce, StarSs, …). • on research enabling future cloud -
Introduction to Computer System
Chapter 1 INTRODUCTION TO COMPUTER SYSTEM 1.0 Objectives 1.1 Introduction –Computer? 1.2 Evolution of Computers 1.3 Classification of Computers 1.4 Applications of Computers 1.5 Advantages and Disadvantages of Computers 1.6 Similarities Difference between computer and Human 1.7 A Computer System 1.8 Components of a Computer System 1.9 Summary 1.10 Check your Progress - Answers 1.11 Questions for Self – Study 1.12 Suggested Readings 1.0 OBJECTIVES After studying this chapter you will be able to: Learn the concept of a system in general and the computer system in specific. Learn and understand how the computers have evolved dramatically within a very short span, from very huge machines of the past, to very compact designs of the present with tremendous advances in technology. Understand the general classifications of computers. Study computer applications. Understand the typical characteristics of computers which are speed, accuracy, efficiency, storage capacity, versatility. Understand limitations of the computer. Discuss the similarities and differences between the human and the computer. Understand the Component of the computer. 1.1 INTRODUCTION- Computer Today, almost all of us in the world make use of computers in one way or the other. It finds applications in various fields of engineering, medicine, commercial, research and others. Not only in these sophisticated areas, but also in our daily lives, computers have become indispensable. They are present everywhere, in all the dev ices that we use daily like cars, games, washing machines, microwaves etc. and in day to day computations like banking, reservations, electronic mails, internet and many more. -
The Strange Birth and Long Life of Unix - IEEE Spectrum Page 1 of 6
The Strange Birth and Long Life of Unix - IEEE Spectrum Page 1 of 6 COMPUTING / SOFTWARE FEATURE The Strange Birth and Long Life of Unix The classic operating system turns 40, and its progeny abound By WARREN TOOMEY / DECEMBER 2011 They say that when one door closes on you, another opens. People generally offer this bit of wisdom just to lend some solace after a misfortune. But sometimes it's actually true. It certainly was for Ken Thompson and the late Dennis Ritchie, two of the greats of 20th-century information technology, when they created the Unix operating system, now considered one of the most inspiring and influential pieces of software ever written. A door had slammed shut for Thompson and Ritchie in March of 1969, when their employer, the American Telephone & Telegraph Co., withdrew from a collaborative project with the Photo: Alcatel-Lucent Massachusetts Institute of KEY FIGURES: Ken Thompson [seated] types as Dennis Ritchie looks on in 1972, shortly Technology and General Electric after they and their Bell Labs colleagues invented Unix. to create an interactive time- sharing system called Multics, which stood for "Multiplexed Information and Computing Service." Time-sharing, a technique that lets multiple people use a single computer simultaneously, had been invented only a decade earlier. Multics was to combine time-sharing with other technological advances of the era, allowing users to phone a computer from remote terminals and then read e -mail, edit documents, run calculations, and so forth. It was to be a great leap forward from the way computers were mostly being used, with people tediously preparing and submitting batch jobs on punch cards to be run one by one. -
The Strange Birth and Long Life of Unix - IEEE Spectrum
The Strange Birth and Long Life of Unix - IEEE Spectrum http://spectrum.ieee.org/computing/software/the-strange-birth-and-long-li... COMPUTING / SOFTWARE FEATURE The Strange Birth and Long Life of Unix The classic operating system turns 40, and its progeny abound By WARREN TOOMEY / DECEMBER 2011 They say that when one door closes on you, another opens. People generally offer this bit of wisdom just to lend some solace after a misfortune. But sometimes it's actually true. It certainly was for Ken Thompson and the late Dennis Ritchie, two of the greats of 20th-century information technology, when they created the Unix operating system, now considered one of the most inspiring and influential pieces of software ever written. A door had slammed shut for Thompson and Ritchie in March of 1969, when their employer, the American Telephone & Telegraph Co., withdrew from a collaborative project with the Photo: Alcatel-Lucent Massachusetts Institute of KEY FIGURES: Ken Thompson [seated] types as Dennis Ritchie looks on in 1972, shortly Technology and General Electric after they and their Bell Labs colleagues invented Unix. to create an interactive time-sharing system called Multics, which stood for "Multiplexed Information and Computing Service." Time-sharing, a technique that lets multiple people use a single computer simultaneously, had been invented only a decade earlier. Multics was to combine time-sharing with other technological advances of the era, allowing users to phone a computer from remote terminals and then read e-mail, edit documents, run calculations, and so forth. It was to be a great leap forward from the way computers were mostly being used, with people tediously preparing and submitting batch jobs on punch cards to be run one by one. -
Plan 9 from Bell Labs
Plan 9 from Bell Labs “UNIX++ Anyone?” Anant Narayanan Malaviya National Institute of Technology FOSS.IN 2007 What is it? Advanced technology transferred via mind-control from aliens in outer space Humans are not expected to understand it (Due apologies to lisperati.com) Yeah Right • More realistically, a distributed operating system • Designed by the creators of C, UNIX, AWK, UTF-8, TROFF etc. etc. • Widely acknowledged as UNIX’s true successor • Distributed under terms of the Lucent Public License, which appears on the OSI’s list of approved licenses, also considered free software by the FSF What For? “Not only is UNIX dead, it’s starting to smell really bad.” -- Rob Pike (circa 1991) • UNIX was a fantastic idea... • ...in it’s time - 1970’s • Designed primarily as a “time-sharing” system, before the PC era A closer look at Unix TODAY It Works! But that doesn’t mean we don’t develop superior alternates GNU/Linux • GNU’s not UNIX, but it is! • Linux was inspired by Minix, which was in turn inspired by UNIX • GNU/Linux (mostly) conforms to ANSI and POSIX requirements • GNU/Linux, on the desktop, is playing “catch-up” with Windows or Mac OS X, offering little in terms of technological innovation Ok, and... • Most of the “modern ideas” we use today were “bolted” on an ancient underlying system • Don’t believe me? A “modern” UNIX Terminal Where did it go wrong? • Early UNIX, “everything is a file” • Brilliant! • Only until people started adding “features” to the system... Why you shouldn’t be working with GNU/Linux • The Socket API • POSIX • X11 • The Bindings “rat-race” • 300 system calls and counting.. -
Squinting at Power Series
Squinting at Power Series M. Douglas McIlroy AT&T Bell Laboratories Murray Hill, New Jersey 07974 ABSTRACT Data streams are an ideal vehicle for handling power series. Stream implementations can be read off directly from simple recursive equations that de®ne operations such as multiplication, substitution, exponentiation, and reversion of series. The bookkeeping that bedevils these algorithms when they are expressed in traditional languages is completely hidden when they are expressed in stream terms. Communicating processes are the key to the simplicity of the algorithms. Working versions are presented in newsqueak, the language of Pike's ``squint'' system; their effectiveness depends critically on the stream protocol. Series and streams Power series are natural objects for stream processing. Pertinent computations are neatly describable by recursive equations. CSP (communicating sequential process) languages1, 2 are good vehicles for implementation. This paper develops the algorithmic ideas and reduces them to practice in a working CSP language,3 not coincidentally illustrating the utility of concurrent programming notions in untangling the logic of some intricate computations on sequences. This elegant approach to power series computation, ®rst demonstrated but never published by Kahn and MacQueen as an application of their data stream system, is still little known.4 Power series are represented as streams of coef®cients, the exponents being given implicitly by ordinal position. (This is an in®nite analogue of the familiar representation of a polynomial as an array of coef®cients.) Thus the power series for the exponential function ∞ 1 1 1 e x = Σ x n / n! = 1 + x + __ x 2 + __ x 3 + ___ x 4 + . -
Uma Introdução À Computação: História E Ciência Editora Ixtlan - São Paulo – 2016
São Paulo – 2016 Copyright © Autores diversos Projeto gráfico: Editora Ixtlan Revisão: Eduardo Telmo Fonseca Santos Milena Montenegro Pereira Diagramação: Márcia Todeschini Capa: Gabriel Polizello Uma introdução à computação: história e ciência Editora Ixtlan - São Paulo – 2016 ISBN: 978-85-8197-510-8 1.Ciência da computação 2.história CDD 000 Editora Ixtlan - CNPJ 11.042.574/0001-49 - I.E. 456166992117 [email protected] – www.editoraixtlan.com DIREITOS PRESERVADOS – É proibida a reprodução total ou parcial, de qualquer forma ou por qualquer meio. A violação dos direitos de autor (Lei Federal 9.610/1998) é crime previsto no art. 184 do Código Penal. Sumário 1. Início da computação - 3 2. Software - 19 3. Representação da Informação - 27 4. Ciência da Computação é Ciência? - 35 5. Rede de Computadores - 37 6. Exercícios Complementares - 49 7. Bibliografia - 53 Cap´ıtulo 1 Início da computação Para entender os fundamentos da computação atual é preciso olhar para o passado e ver como essa disciplina/área foi fundada e como vem se desenvolvendo até a atualidade [5]. Uma das bases da computação é a Matemática. Desde os primórdios o ser humano percebeu a necessidade de desenvolver algo para auxiliá-lo nas mais diversas operações. Essa necessidade é a responsável pelo surgimento desde as máquinas de calcular até as mais diversas máquinas utilizadas no mundo todo. Em torno de 2600 anos a.C., surgiu um dos primeiros instrumentos manuais voltados para ajudar o homem a calcular quantias numéricas. Esse instrumento usado para representação dos números era o ábaco chinês, que apesar do tempo em que surgiu, ainda é comumente utilizado em certas localidades. -
Universidad Nacional Autónoma De México, Por Permitirme El Honor De Formar Parte De Ella
Universidad Nacional Autónoma de México FACULTAD DE INGENIERÍA “SISTEMA DE MONITOREO DE SERVIDORES UNIX” T E S I S Que para obtener el Título de: INGENIERO EN COMPUTACIÓN P r e s e n t a: EDGAR CRISTÓBAL RAMÍREZ MIRANDA Director de Tesis: Ing. Noé Cruz Marín Agradecimientos Más que gracias, mi eterno amor a mi padre, mi madre y a mis hermanos a los cuales les debo lo que soy. Papá te admiro y respeto profundamente por la rectitud y honradez con la que te conduces a cada paso de tu vida, por el apoyo y dirección que siempre de ti he recibido, por todas las enseñanzas que desde chico recibí de ti y espero seguir recibiendo. Mamá te amo por todos los años de dedicación que me has dado, por los desvelos, por las lágrimas, por los cariños, por tu inmensa ternura y compasión, por que no encuentro ni encontraré jamás la forma de pagarte todo lo que me has dado, gracias. A mi hermano Emilio por ser mi amigo, por enseñarme a defenderme, por ser mi ídolo, por ensañarme a no desistir nunca hasta alcanzar las metas, porque a tu lado siempre me sentí protegido, por alentarme a ser ingeniero. A mi hermano Joaquín, por que de ti aprendí a ser más sereno a pensar antes de actuar, por siempre protegerme de todos sin importarte nada, por estar conmigo en las buenas y en las malas, por tu tolerancia, por ser mi amigo en los tiempos difíciles. Gracias por aguantarme, soportarme, cuidarme y quererme de la forma en la que lo hacen, estoy y siempre estaré orgulloso de pertenecer a la familia Ramírez Miranda.