A Plan 9 / Linux Distribution
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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. -
CSE 220: Systems Programming Input and Output
CSE 220: Systems Programming Input and Output Ethan Blanton Department of Computer Science and Engineering University at Buffalo Introduction Unix I/O Standard I/O Buffering Summary References I/O Kernel Services We have seen some text I/O using the C Standard Library. printf() fgetc() … However, all I/O is built on kernel system calls. In this lecture, we’ll look at those services vs. standard I/O. © 2020 Ethan Blanton / CSE 220: Systems Programming Introduction Unix I/O Standard I/O Buffering Summary References Everything is a File These services are particularly important on Unix systems. On Unix, “everything is a file”. Many devices and services are accessed by opening device nodes. Device nodes behave like (but are not) files. Examples: /dev/null: Always readable, contains no data. Always writable, discards anything written to it. /dev/urandom: Always readable, reads a cryptographically secure stream of random data. © 2020 Ethan Blanton / CSE 220: Systems Programming Introduction Unix I/O Standard I/O Buffering Summary References File Descriptors All access to files is through file descriptors. A file descriptor is a small integer representing an open file in a particular process. There are three “standard” file descriptors: 0: standard input 1: standard output 2: standard error …sound familiar? (stdin, stdout, stderr) © 2020 Ethan Blanton / CSE 220: Systems Programming Introduction Unix I/O Standard I/O Buffering Summary References System Call Failures Kernel I/O (and most other) system calls return -1 on failure. When this happens, the global variable errno is set to a reason. Include errno.h to define errno in your code. -
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. -
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 Unix
Introduction to Unix Rob Funk <[email protected]> University Technology Services Workstation Support http://wks.uts.ohio-state.edu/ University Technology Services Course Objectives • basic background in Unix structure • knowledge of getting started • directory navigation and control • file maintenance and display commands • shells • Unix features • text processing University Technology Services Course Objectives Useful commands • working with files • system resources • printing • vi editor University Technology Services In the Introduction to UNIX document 3 • shell programming • Unix command summary tables • short Unix bibliography (also see web site) We will not, however, be covering these topics in the lecture. Numbers on slides indicate page number in book. University Technology Services History of Unix 7–8 1960s multics project (MIT, GE, AT&T) 1970s AT&T Bell Labs 1970s/80s UC Berkeley 1980s DOS imitated many Unix ideas Commercial Unix fragmentation GNU Project 1990s Linux now Unix is widespread and available from many sources, both free and commercial University Technology Services Unix Systems 7–8 SunOS/Solaris Sun Microsystems Digital Unix (Tru64) Digital/Compaq HP-UX Hewlett Packard Irix SGI UNICOS Cray NetBSD, FreeBSD UC Berkeley / the Net Linux Linus Torvalds / the Net University Technology Services Unix Philosophy • Multiuser / Multitasking • Toolbox approach • Flexibility / Freedom • Conciseness • Everything is a file • File system has places, processes have life • Designed by programmers for programmers University Technology Services -
Storage Devices, Basic File System Design
CS162 Operating Systems and Systems Programming Lecture 17 Data Storage to File Systems October 29, 2019 Prof. David Culler http://cs162.eecs.Berkeley.edu Read: A&D Ch 12, 13.1-3.2 Recall: OS Storage abstractions Key Unix I/O Design Concepts • Uniformity – everything is a file – file operations, device I/O, and interprocess communication through open, read/write, close – Allows simple composition of programs • find | grep | wc … • Open before use – Provides opportunity for access control and arbitration – Sets up the underlying machinery, i.e., data structures • Byte-oriented – Even if blocks are transferred, addressing is in bytes What’s below the surface ?? • Kernel buffered reads – Streaming and block devices looks the same, read blocks yielding processor to other task • Kernel buffered writes Application / Service – Completion of out-going transfer decoupled from the application, File descriptor number allowing it to continue - an int High Level I/O streams • Explicit close Low Level I/O handles 9/12/19 The cs162file fa19 L5system abstraction 53 Syscall registers • File File System descriptors File Descriptors – Named collection of data in a file system • a struct with all the info I/O Driver Commands and Data Transfers – POSIX File data: sequence of bytes • about the files Disks, Flash, Controllers, DMA Could be text, binary, serialized objects, … – File Metadata: information about the file • Size, Modification Time, Owner, Security info • Basis for access control • Directory – “Folder” containing files & Directories – Hierachical -
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. -
File and Console I/O
File and Console I/O CS449 Spring 2016 What is a Unix(or Linux) File? • File: “a resource for storing information [sic] based on some kind of durable storage” (Wikipedia) • Wider sense: “In Unix, everything is a file.” (a.k.a “In Unix, everything is a stream of bytes.”) – Traditional files, directories, links – Inter-process communication (pipes, shared memory, sockets) – Devices (interactive terminals, hard drives, printers, graphic card) • Usually mounted under /dev/ directory – Process Links (for getting process information) • Usually mounted under /proc/ directory Stream of Bytes Abstraction • A file, in abstract, is a stream of bytes • Can be manipulated using five system calls: – open: opens a file for reading/writing and returns a file descriptor • File descriptor: index into an OS array called open file table – read: reads current offset through file descriptor – write: writes current offset through file descriptor – lseek: changes current offset in file – close: closes file descriptor • Some files do not support certain operations (e.g. a terminal device does not support lseek) C Standard Library Wrappers • C Standard Library wraps file system calls in library functions – For portability across multiple systems – To provide additional features (buffering, formatting) • All C wrappers buffered by default – Buffering can be controlled using “setbuf” or “setlinebuf” calls (remember those?) • Works on FILE * instead of file descriptor – FILE is a library data structure that abstracts a file – Contains file descriptor, current offset, buffering mode etc. Wrappers for the Five System Calls Function Prototype Description FILE *fopen(const char *path, const Opens the file whose name is the string pointed to char *mode); by path and associates a stream with it. -
A Platform Architecture for Sensor Data Processing and Verification in Buildings
A Platform Architecture for Sensor Data Processing and Verification in Buildings Jorge Ortiz Electrical Engineering and Computer Sciences University of California at Berkeley Technical Report No. UCB/EECS-2013-196 http://www.eecs.berkeley.edu/Pubs/TechRpts/2013/EECS-2013-196.html December 3, 2013 Copyright © 2013, by the author(s). All rights reserved. Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. To copy otherwise, to republish, to post on servers or to redistribute to lists, requires prior specific permission. A Platform Architecture for Sensor Data Processing and Verification in Buildings by Jorge Jose Ortiz A dissertation submitted in partial satisfaction of the requirements for the degree of Doctor of Philosophy in Computer Science in the Graduate Division of the University of California, Berkeley Committee in charge: Professor David E. Culler, Chair Professor Randy H. Katz Professor Paul Wright Fall 2013 A Platform Architecture for Sensor Data Processing and Verification in Buildings Copyright 2013 by Jorge Jose Ortiz 1 Abstract A Platform Architecture for Sensor Data Processing and Verification in Buildings by Jorge Jose Ortiz Doctor of Philosophy in Computer Science University of California, Berkeley Professor David E. Culler, Chair This thesis examines the state of the art of building information systems and evaluates their architecture in the context of emerging technologies and applications for deep analysis of the built environment. -
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.. -
Workstation Operating Systems Mac OS 9
15-410 “Now that we've covered the 1970's...” Plan 9 Nov. 25, 2019 Dave Eckhardt 1 L11_P9 15-412, F'19 Overview “The land that time forgot” What style of computing? The death of timesharing The “Unix workstation problem” Design principles Name spaces File servers The TCP file system... Runtime environment 3 15-412, F'19 The Land That Time Forgot The “multi-core revolution” already happened once 1982: VAX-11/782 (dual-core) 1984: Sequent Balance 8000 (12 x NS32032) 1985: Encore MultiMax (20 x NS32032) 1990: Omron Luna88k workstation (4 x Motorola 88100) 1991: KSR1 (1088 x KSR1) 1991: “MCS” paper on multi-processor locking algorithms 1995: BeBox workstation (2 x PowerPC 603) The Land That Time Forgot The “multi-core revolution” already happened once 1982: VAX-11/782 (dual-core) 1984: Sequent Balance 8000 (12 x NS32032) 1985: Encore MultiMax (20 x NS32032) 1990: Omron Luna88k workstation (4 x Motorola 88100) 1991: KSR1 (1088 x KSR1) 1991: “MCS” paper on multi-processor locking algorithms 1995: BeBox workstation (2 x PowerPC 603) Wow! Why was 1995-2004 ruled by single-core machines? What operating systems did those multi-core machines run? The Land That Time Forgot Why was 1995-2004 ruled by single-core machines? In 1995 Intel + Microsoft made it feasible to buy a fast processor that fit on one chip, a fast I/O bus, multiple megabytes of RAM, and an OS with memory protection. Everybody could afford a “workstation”, so everybody bought one. Massive economies of scale existed in the single- processor “Wintel” universe.