Openbsd Frequently Asked Questions

Total Page:16

File Type:pdf, Size:1020Kb

Openbsd Frequently Asked Questions OpenBSD Frequently Asked Questions Language: en [teams] de fr nl pl pt Documentation and Frequently Other Documents Asked Questions Upgrade Guide Following -current Commonly Encountered Issues Recent updates Port Testing Guide Using AnonCVS Stable This FAQ is supplemental documentation to the man pages, available both in the installed Using CVSup system and online. The FAQ covers the active release of OpenBSD, currently v3.8. There Manual pages are likely features and changes to features in the development version (-current) of Bug Reporting OpenBSD that are not covered in this FAQ. Mail lists PF User's Guide The FAQ in PDF and plain text form is available in the pub/OpenBSD/doc directory OpenSSH FAQ from the FTP mirrors, along with other documents. PDF files OpenBSD FAQ PF User's Guide 1 - Introduction to OpenBSD Text files ● 1.1 - What is OpenBSD? ● OpenBSD FAQ 1.2 - On what systems does OpenBSD run? ● PF User's Guide 1.3 - Is OpenBSD really free? ● 1.4 - Why might I want to use OpenBSD? ● 1.5 - How can I help support OpenBSD? Back to OpenBSD ● 1.6 - Who maintains OpenBSD? ● 1.7 - When is the next release of OpenBSD? ● 1.8 - What is included with OpenBSD? ● 1.9 - What is new in OpenBSD 3.8? ● 1.10 - Can I use OpenBSD as a desktop system? ● 1.11 - Why is/isn't ProductX included? 2 - Other OpenBSD Information Resources ● 2.1 - Web Pages ● 2.2 - Mailing Lists ● 2.3 - Manual Pages ● 2.4 - Reporting Bugs 3 - Obtaining OpenBSD ● 3.1 - Buying an OpenBSD CD set ● 3.2 - Buying OpenBSD T-Shirts ● 3.3 - Does OpenBSD provide an ISO image for download? http://www.openbsd.org/faq/index.html (1 of 7) [19/04/2006 23:03:44] OpenBSD Frequently Asked Questions ● 3.4 - Downloading via FTP, HTTP or AFS ● 3.5 - Obtaining Current Source Code 4 - OpenBSD 3.8 Installation Guide ● 4.1 - Overview of the OpenBSD installation procedure. ● 4.2 - Pre-installation checklist ● 4.3 - Creating bootable OpenBSD install media ● 4.4 - Booting OpenBSD install media ● 4.5 - Performing an install ● 4.6 - What files are needed for Installation? ● 4.7 - How much space do I need for an OpenBSD installation? ● 4.8 - Multibooting OpenBSD ● 4.9 - Sending your dmesg to [email protected] after the install ● 4.10 - Adding a file set after install ● 4.11 - What is 'bsd.rd'? ● 4.12 - Common installation problems ● 4.13 - Customizing the install process ● 4.14 - How can I install a number of similar systems? ● 4.15 - How can I get a dmesg(8) to report an install problem? ● 4.16 - Upgrading/reinstalling OpenBSD/i386 using bsd.rd-a.out. 5 - Building the System from Source ● 5.1 - OpenBSD's Flavors ● 5.2 - Why should I build my system from source? ● 5.3 - Building OpenBSD from source ● 5.4 - Building a release ● 5.5 - Building X ● 5.6 - Why do I need a custom kernel? ● 5.7 - Building a custom kernel ● 5.8 - Boot-time configuration ● 5.9 - Using config(8) to change your kernel ● 5.10 - Getting more verbose output during boot ● 5.11 - Common Problems when Compiling and Building 6 - Networking ● 6.1 - Before we go any further ● 6.2 - Initial network setup ● 6.3 - How do I filter and firewall with OpenBSD? ● 6.4 - Dynamic Host Configuration Protocol (DHCP) ● 6.5 - Point to Point Protocol ● 6.6 - Tuning networking parameters ● 6.7 - Using NFS ● 6.9 - Setting up a bridge with OpenBSD ● 6.10 - How do I boot using PXE? ● 6.11 - The Common Address Redundancy Protocol (CARP) ● 6.12 - Using OpenNTPD http://www.openbsd.org/faq/index.html (2 of 7) [19/04/2006 23:03:44] OpenBSD Frequently Asked Questions ● 6.13 - What are my wireless networking options? 7 - Keyboard and Display Controls ● 7.1 - How do I remap the keyboard? (wscons) ● 7.2 - Is there console mouse support in OpenBSD? ● 7.3 - How do I clear the console each time a user logs out? ● 7.4 - Accessing the console scrollback buffer. (amd64, i386, some Alpha) ● 7.5 - How do I switch consoles? (amd64, i386, Zaurus, some Alpha) ● 7.6 - How can I use a console resolution of 80x50? (amd64, i386) ● 7.7 - How do I use a serial console? ● 7.8 - How do I blank my console? (wscons) ● 7.9 - EVERYTHING I TYPE AT THE LOGIN PROMPT IS IN CAPS! 8 - General Questions ● 8.1 - I forgot my root password... What do I do! ● 8.2 - X won't start, I get lots of error messages ● 8.3 - Can I use programming language "L" on OpenBSD? ● 8.8 - Is there any way to use my floppy drive if it's not attached during boot? ● 8.9 - OpenBSD Bootloader (i386 amd64 specific) ● 8.10 - Using S/Key on your OpenBSD system ● 8.12 - Does OpenBSD support SMP? ● 8.13 - I sometimes get Input/output error when trying to use my tty devices ● 8.14 - What web browsers are available for OpenBSD? ● 8.15 - How do I use the mg editor? ● 8.16 - Ksh does not appear to read my .profile! ● 8.17 - Why does my /etc/motd file get written over when I modified it? ● 8.18 - Why does www.openbsd.org run on Solaris? ● 8.20 - Antialiased and TrueType fonts in X ● 8.21 - Does OpenBSD support any journaling filesystems? ● 8.22 - Reverse DNS or Why is it taking so long for me to log in? ● 8.23 - Why do the OpenBSD web pages not conform to HTML4/XHTML? ● 8.24 - Why is my clock off by twenty-some seconds? ● 8.25 - Why is my clock off by several hours? 9 - Migrating to OpenBSD ● 9.1 - Tips for users of other Unix-like Operating Systems ● 9.2 - Dual boot of Linux and OpenBSD ● 9.3 - Converting your Linux (or other Sixth Edition-style) password file to BSD- style. ● 9.4 - Running Linux binaries on OpenBSD ● 9.5 - Accessing your Linux files from OpenBSD 10 - System Management ● 10.1 - When I try to su to root it says that I'm in the wrong group http://www.openbsd.org/faq/index.html (3 of 7) [19/04/2006 23:03:44] OpenBSD Frequently Asked Questions ● 10.2 - How do I duplicate a filesystem? ● 10.3 - How do I start daemons with the system? (Overview of rc(8)) ● 10.4 - Why do users get relaying access denied when they are remotely sending mail through my OpenBSD system? ● 10.5 - I've set up POP, but I get errors when accessing my mail through POP. What can I do? ● 10.6 - Why does Sendmail ignore /etc/hosts file? ● 10.7 - Setting up a Secure HTTP Server using SSL(8) ● 10.8 - I made changes to /etc/passwd with vi(1), but the changes didn't seem to take place. Why? ● 10.9 - How do I add a user? or delete a user? ● 10.10 - How do I create a ftp-only account? ● 10.11 - Setting up user disk quotas ● 10.12 - Setting up KerberosV Clients and Servers ● 10.13 - Setting up an Anonymous FTP Server ● 10.14 - Confining users to their home directories in ftpd(8). ● 10.15 - Applying patches in OpenBSD. ● 10.16 - Tell me about chroot() Apache? ● 10.17 - Can I change the root shell? ● 10.18 - What else can I do with ksh? 12 - Platform-Specific Questions ● 12.1 - General hardware notes ● 12.2 - DEC Alpha ● 12.3 - AMD 64 ● 12.4 - CATS ARM development board ● 12.5 - HP 9000 series 300, 400 ● 12.6 - HPPA ● 12.7 - i386 ● 12.8 - Mac68k ● 12.9 - MacPPC ● 12.10 - MVME68k ● 12.11 - MVME88k ● 12.12 - SPARC ● 12.13 - UltraSPARC ● 12.14 - DEC VAX 13 - Multimedia ● 13.1 - How do I configure my audio device? ● 13.2 - Playing different kinds of audio ● 13.3 - How can I play audio CDs in OpenBSD? ● 13.4 - Can I use OpenBSD to record audio samples? ● 13.5 - Tell me about Ogg Vorbis and MP3 encoding? ● 13.6 - How can I playback video DVDs in OpenBSD? ● 13.7 - How do I burn CDs and DVDs? ● 13.8 - But I want my media files in format FOO. ● 13.9 - Is it possible to play streaming media under OpenBSD? ● 13.10 - Can I have Java and/or Flash plugins in my web browser? (i386 only) http://www.openbsd.org/faq/index.html (4 of 7) [19/04/2006 23:03:44] OpenBSD Frequently Asked Questions 14 - Disk Setup ● 14.1 - Using OpenBSD's disklabel(8) ● 14.2 - Using OpenBSD's fdisk(8) ● 14.3 - Adding extra disks in OpenBSD ● 14.4 - How to swap to a file ● 14.5 - Soft Updates ● 14.6 - How does OpenBSD/i386 boot? ● 14.7 - What are the issues regarding large drives with OpenBSD? ● 14.8 - Installing Bootblocks - i386 specific ● 14.9 - Preparing for disaster: Backing up and Restoring from tape. ● 14.10 - Mounting disk images in OpenBSD ● 14.11 - Help! I'm getting errors with IDE DMA! ● 14.13 - RAID options with OpenBSD ● 14.14 - Why does df(1) tell me I have over 100% of my disk used? ● 14.15 - Recovering partitions after deleting the disklabel ● 14.16 - Can I access data on filesystems other than FFS? ● 14.17 - Can I use a flash memory device with OpenBSD? ● 14.18 - Optimizing disk performance ● 14.19 - Why aren't we using async mounts? 15 - The OpenBSD packages and ports system ● 15.1 - Introduction ● 15.2 - Package management ● 15.3 - Working with ports ● 15.4 - FAQ ● 15.5 - Reporting problems ● 15.6 - Helping us PF User's Guide ● Basic Configuration ❍ Getting Started ❍ Lists and Macros ❍ Tables ❍ Packet Filtering ❍ Network Address Translation ❍ Traffic Redirection (Port Forwarding) ❍ Shortcuts For Creating Rulesets ● Advanced Configuration ❍ Runtime Options ❍ Scrub (Packet Normalization) ❍ Anchors ❍ Packet Queueing and Prioritization ❍ Address Pools and Load Balancing ❍ Packet Tagging (Policy Filtering) ● Additional Topics http://www.openbsd.org/faq/index.html (5 of 7) [19/04/2006 23:03:44] OpenBSD Frequently Asked Questions ❍ Logging ❍ Performance ❍ Issues with FTP ❍ Authpf: User Shell for Authenticating Gateways ❍ Firewall Redundancy with CARP and pfsync ● Example Rulesets ❍ Firewall for Home or Small Office Commonly Encountered Issues ● Common Installation Problems ● How do I upgrade my system? ● Packet Filter ● Should I use Ports or Packages? ● How do I set up a multi-boot system? ● Hard disk DMA errors ● Wireless networking options Recent Updates ● FAQ 8 - Can I use programming language "L" on OpenBSD? - new ● Upgrade Guide - new ● FAQ 15 - Packages and Ports - new ● FAQ 13 - using Java and Flash - new ● FAQ 14 - Can I access data on filesystems other than FFS? - new ● FAQ 14 - Can I use a flash memory device with OpenBSD? - new ● FAQ 13 - Multimedia - new The FAQ maintainers are Nick Holland, Joel Knight, and Steven Mestdagh.
Recommended publications
  • Educational Directory, 1
    DEPARTMENT OF THEINTERIOR BUREAU OF EDUCATION BULLETIN, 1922, No.50, EDUCATIONALDIRECTORY 1922-1923 WASHINGTON GOVERNMENT PRINTING OFFICE 1923 A u ADDITIONAL COPIES OP THIS PUBLICATION MAY BE PROCURED rams THE SUPERINTENDENT OF DOCUMENTS GOVERNMENT PRINTING OFFICE WASHINGTON, AT 115 CENTS PER COPY PURCHASER AGREES NOT TO RESELL 1SR DISTRIBUTE THIS COPT TOR PROT1T.-P1111. RES. S7, APPROVED MAY 11, 1923 IL CONTENTS. I. The United StatesBureau of Education Page: II. Principal State school officers 1 III. County and other local 3 superintendents of schools.- 13 IV. Superintendents of prIblic schools in cities and towns. 46 V. Presidents of universities andcolleges VI. Presidents of junior 67 77 VII. Heads 9f departm nts ofeducation 78 N111 I. Presidentsor deans of schools of theology 87 IX. Presidents or deans of schools of law 90 X. Presidents or deans of schools of tiielicine 92 XI. Presidents or deans of schools of dentistry 94 Presidents or deans of schools of pharmacy.. XII I. Presidents of schools of 94' osteopathy 96 X IV. Presidents or deans of srliools of veterinary medicine 96 XV. Presidents, etc.. of institutionsfor the training of teachers: 1. Presidents of teachers' colleges. 96 II. Principals of normal training schools: 1. Public normal sclu 99 2. Private normal selfols 104 'III. Directors of kindergarten training incolleges, normal schools, and kindergarten training 84110eild 105 XVI. Directors of.summer schools 109 XVII. Librarians of Public and society Librai 126 XVIII. Executive officers of State library 151 X IX. Directors of librafy schools 152 X X. Educational boards and foundations X X I. Church. educational boards and 152 societies.
    [Show full text]
  • Gigabit Ethernet - CH 3 - Ethernet, Fast Ethernet, and Gigabit Ethern
    Switched, Fast, and Gigabit Ethernet - CH 3 - Ethernet, Fast Ethernet, and Gigabit Ethern.. Page 1 of 36 [Figures are not included in this sample chapter] Switched, Fast, and Gigabit Ethernet - 3 - Ethernet, Fast Ethernet, and Gigabit Ethernet Standards This chapter discusses the theory and standards of the three versions of Ethernet around today: regular 10Mbps Ethernet, 100Mbps Fast Ethernet, and 1000Mbps Gigabit Ethernet. The goal of this chapter is to educate you as a LAN manager or IT professional about essential differences between shared 10Mbps Ethernet and these newer technologies. This chapter focuses on aspects of Fast Ethernet and Gigabit Ethernet that are relevant to you and doesn’t get into too much technical detail. Read this chapter and the following two (Chapter 4, "Layer 2 Ethernet Switching," and Chapter 5, "VLANs and Layer 3 Switching") together. This chapter focuses on the different Ethernet MAC and PHY standards, as well as repeaters, also known as hubs. Chapter 4 examines Ethernet bridging, also known as Layer 2 switching. Chapter 5 discusses VLANs, some basics of routing, and Layer 3 switching. These three chapters serve as a precursor to the second half of this book, namely the hands-on implementation in Chapters 8 through 12. After you understand the key differences between yesterday’s shared Ethernet and today’s Switched, Fast, and Gigabit Ethernet, evaluating products and building a network with these products should be relatively straightforward. The chapter is split into seven sections: l "Ethernet and the OSI Reference Model" discusses the OSI Reference Model and how Ethernet relates to the physical (PHY) and Media Access Control (MAC) layers of the OSI model.
    [Show full text]
  • The Title Title: Subtitle March 2007
    sub title The Title Title: Subtitle March 2007 Copyright c 2006-2007 BSD Certification Group, Inc. Permission to use, copy, modify, and distribute this documentation for any purpose with or without fee is hereby granted, provided that the above copyright notice and this permission notice appear in all copies. THE DOCUMENTATION IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS DOCUMENTATION INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CON- SEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEG- LIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS DOCUMENTATION. NetBSD and pkgsrc are registered trademarks of the NetBSD Foundation, Inc. FreeBSD is a registered trademark of the FreeBSD Foundation. Contents Introduction vii 1 Installing and Upgrading the OS and Software 1 1.1 Recognize the installation program used by each operating system . 2 1.2 Recognize which commands are available for upgrading the operating system 6 1.3 Understand the difference between a pre-compiled binary and compiling from source . 8 1.4 Understand when it is preferable to install a pre-compiled binary and how to doso ...................................... 9 1.5 Recognize the available methods for compiling a customized binary . 10 1.6 Determine what software is installed on a system . 11 1.7 Determine which software requires upgrading . 12 1.8 Upgrade installed software . 12 1.9 Determine which software have outstanding security advisories .
    [Show full text]
  • BSD – Alternativen Zu Linux
    ∗BSD { Alternativen zu Linux Karl Lockhoff March 19, 2015 Inhaltsverzeichnis I Woher kommt BSD? I Was ist BSD? I Was ist sind die Unterschiede zwischen FreeBSD, NetBSD und OpenBSD? I Warum soll ich *BSD statt Linux einsetzen? I Chuck Haley und Bill Joy entwickeln den vi in Berkeley I Bill Joy erstellt eine Sammlung von Tools, 1BSD I Unix Version 7 erscheint I 2BSD erscheint (Basis f¨urdie Weiterentwicklung PDP-11) I 3BSD erscheint (erstmalig mit einen eigenen Kernel) I 4BSD erscheint (enth¨altdas fast file system (ffs)) I Bill Joy wechselt zu Sun Microsystems I Kirk McKusick ¨ubernimmt die Entwicklung von BSD I 1978 I 1979 I 1980 I 1981 Woher kommt BSD? I 1976 I Unix Version 6 erscheint I 2BSD erscheint (Basis f¨urdie Weiterentwicklung PDP-11) I 3BSD erscheint (erstmalig mit einen eigenen Kernel) I 4BSD erscheint (enth¨altdas fast file system (ffs)) I Bill Joy wechselt zu Sun Microsystems I Kirk McKusick ¨ubernimmt die Entwicklung von BSD I Bill Joy erstellt eine Sammlung von Tools, 1BSD I Unix Version 7 erscheint I 1979 I 1980 I 1981 Woher kommt BSD? I 1976 I Unix Version 6 erscheint I 1978 I Chuck Haley und Bill Joy entwickeln den vi in Berkeley I 2BSD erscheint (Basis f¨urdie Weiterentwicklung PDP-11) I 3BSD erscheint (erstmalig mit einen eigenen Kernel) I 4BSD erscheint (enth¨altdas fast file system (ffs)) I Bill Joy wechselt zu Sun Microsystems I Kirk McKusick ¨ubernimmt die Entwicklung von BSD I Unix Version 7 erscheint I 1979 I 1980 I 1981 Woher kommt BSD? I 1976 I Unix Version 6 erscheint I 1978 I Chuck Haley und Bill Joy entwickeln den
    [Show full text]
  • Active-Active Firewall Cluster Support in Openbsd
    Active-Active Firewall Cluster Support in OpenBSD David Gwynne School of Information Technology and Electrical Engineering, University of Queensland Submitted for the degree of Bachelor of Information Technology COMP4000 Special Topics Industry Project February 2009 to leese, who puts up with this stuff ii Acknowledgements I would like to thank Peter Sutton for allowing me the opportunity to do this work as part of my studies at the University of Queensland. A huge thanks must go to Ryan McBride for answering all my questions about pf and pfsync in general, and for the many hours working with me on this problem and helping me test and debug the code. Thanks also go to Theo de Raadt, Claudio Jeker, Henning Brauer, and everyone else at the OpenBSD network hackathons who helped me through this. iii Abstract The OpenBSD UNIX-like operating system has developed several technologies that make it useful in the role of an IP router and packet filtering firewall. These technologies include support for several standard routing protocols such as BGP and OSPF, a high performance stateful IP packet filter called pf, shared IP address and fail-over support with CARP (Common Address Redundancy Protocol), and a protocol called pfsync for synchronisation of the firewalls state with firewalls over a network link. These technologies together allow the deployment of two or more computers to provide redundant and highly available routers on a network. However, when performing stateful filtering of the TCP protocol with pf, the routers must be configured in an active-passive configuration due to the current semantics of pfsync.
    [Show full text]
  • BSD UNIX Toolbox: 1000+ Commands for Freebsd, Openbsd and Netbsd Christopher Negus, Francois Caen
    To purchase this product, please visit https://www.wiley.com/en-bo/9780470387252 BSD UNIX Toolbox: 1000+ Commands for FreeBSD, OpenBSD and NetBSD Christopher Negus, Francois Caen E-Book 978-0-470-38725-2 April 2008 $16.99 DESCRIPTION Learn how to use BSD UNIX systems from the command line with BSD UNIX Toolbox: 1000+ Commands for FreeBSD, OpenBSD and NetBSD. Learn to use BSD operation systems the way the experts do, by trying more than 1,000 commands to find and obtain software, monitor system health and security, and access network resources. Apply your newly developed skills to use and administer servers and desktops running FreeBSD, OpenBSD, NetBSD, or any other BSD variety. Become more proficient at creating file systems, troubleshooting networks, and locking down security. ABOUT THE AUTHOR Christopher Negus served for eight years on development teams for the UNIX operating system at the AT&T labs, where UNIX was created and developed. He also worked with Novell on UNIX and UnixWare development. Chris is the author of the bestselling Fedora and Red Hat Linux Bible series, Linux Toys II, Linux Troubleshooting Bible, and Linux Bible 2008 Edition. Francois Caen hosts and manages business application infrastructures through his company Turbosphere LLC. As an open- source advocate, he has lectured on OSS network management and Internet services, and served as president of the Tacoma Linux User Group. He is a Red Hat Certified Engineer (RHCE). To purchase this product, please visit https://www.wiley.com/en-bo/9780470387252.
    [Show full text]
  • Love Hörnquist-Åstrand Assar Westerlund Harald Barth
    Arla A Free AFS implementation from KTH Edition 0.1, for version 0.34 1999 - 2000 Love H¨ornquist-Astrand˚ Assar Westerlund Harald Barth last updated $Date: 2000/10/01 19:18:41 $ Copyright (c) 1998 - 1999 Kungliga Tekniska H¨ogskolan (Royal Institute of Technology, Stock- holm, Sweden). 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 condi- tions and the following disclaimer in the documentation and/or other materials provided with the distribution. 3. All advertising materials mentioning features or use of this software must display the following acknowledgement: This product includes software developed by Kungliga Tekniska H¨ogskolan and its contributors. 4. Neither the name of the Institute 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 INSTITUTE AND CONTRIBUTORS \AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PAR- TICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THE- ORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (IN- CLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
    [Show full text]
  • Debugging Kernel Problems
    Debugging Kernel Problems by GregLehey Edition for AsiaBSDCon 2004 Taipei, 13 March 2004 Debugging Kernel Problems by GregLehey([email protected]) Copyright © 1995-2004 GregLehey 3Debugging Kernel Problems Preface Debugging kernel problems is a black art. Not manypeople do it, and documentation is rare, in- accurate and incomplete. This document is no exception: faced with the choice of accuracyand completeness, I chose to attempt the latter.Asusual, time was the limiting factor,and this draft is still in beta status. This is a typical situation for the whole topic of kernel debugging: building debug tools and documentation is expensive,and the people who write them are also the people who use them, so there'satendencytobuild as much of the tool as necessary to do the job at hand. If the tool is well-written, it will be reusable by the next person who looks at a particular area; if not, it might fall into disuse. Consider this book a starting point for your own develop- ment of debugging tools, and remember: more than anywhere else, this is an area with ``some as- sembly required''. Debugging Kernel Problems 4 1 Introduction Operating systems fail. All operating systems contain bugs, and theywill sometimes cause the system to behave incorrectly.The BSD kernels are no exception. Compared to most other oper- ating systems, both free and commercial, the BSD kernels offer a large number of debugging tools. This tutorial examines the options available both to the experienced end user and also to the developer. In this tutorial, we’ll look at the following topics: • Howand whykernels fail.
    [Show full text]
  • Ethernet and Wifi
    Ethernet and WiFi hp://xkcd.com/466/ CSCI 466: Networks • Keith Vertanen • Fall 2011 Overview • Mul?ple access networks – Ethernet • Long history • Dominant wired technology – 802.11 • Dominant wireless technology 2 Classic Ethernet • Ethernet – luminferous ether through which electromagne?c radiaon once thought to propagate – Carrier Sense, Mul?ple Access with Collision Detec?on (CSMA/CD) – IEEE 802.3 Robert Metcalfe, co- inventor of Ethernet 3 Classic Ethernet • Ethernet – Xerox Ethernet standardized as IEEE 802.3 in 1983 – Xerox not interested in commercializing – Metcalfe leaves and forms 3Com 4 Ethernet connec?vity • Shared medium – All hosts hear all traffic on cable – Hosts tapped the cable – 2500m maximum length – May include repeaters amplifying signal – 10 Mbps bandwidth 5 Classic Ethernet cabling Cable aSer being "vampire" tapped. Thick Ethernet cable (yellow), 10BASE-5 transceivers, cable tapping tool (orange), 500m maximum length. Thin Ethernet cable (10BASE2) with BNC T- connector, 185m maximum length. 6 Ethernet addressing • Media Access Control address (MAC) – 48-bit globally unique address • 281,474,976,710,656 possible addresses • Should last ?ll 2100 • e.g. 01:23:45:67:89:ab – Address of all 1's is broadcast • FF:FF:FF:FF:FF:FF 7 Ethernet frame format • Frame format – Manchester encoded – Preamble products 10-Mhz square wave • Allows clock synch between sender & receiver – Pad to at least 64-bytes (collision detec?on) Ethernet 802.3 AlternaWng 0's 48-bit MAC and 1's (except addresses SoF of 11) 8 Ethernet receivers • Hosts listens to medium – Deliver to host: • Any frame with host's MAC address • All broadcast frames (all 1's) • Mul?cast frames (if subscribed to) • Or all frames if in promiscuous mode 9 MAC sublayer • Media Access Control (MAC) sublayer – Who goes next on a shared medium – Ethernet hosts can sense if medium in use – Algorithm for sending data: 1.
    [Show full text]
  • Master Boot Record Vs Guid Mac
    Master Boot Record Vs Guid Mac Wallace is therefor divinatory after kickable Noach excoriating his philosophizer hourlong. When Odell perches dilaceratinghis tithes gravitated usward ornot alkalize arco enough, comparatively is Apollo and kraal? enduringly, If funked how or following augitic is Norris Enrico? usually brails his germens However, half the UEFI supports the MBR and GPT. Following your suggested steps, these backups will appear helpful to restore prod data. OK, GPT makes for playing more logical choice based on compatibility. Formatting a suit Drive are Hard Disk. In this guide, is welcome your comments or thoughts below. Thus, making, or paid other OS. Enter an open Disk Management window. Erase panel, or the GUID Partition that, we have covered the difference between MBR and GPT to care unit while partitioning a drive. Each record in less directory is searched by comparing the hash value. Disk Utility have to its important tasks button activated for adding, total capacity, create new Container will be created as well. Hard money fix Windows Problems? MBR conversion, the main VBR and the backup VBR. At trial three Linux emergency systems ship with GPT fdisk. In else, the user may decide was the hijack is unimportant to them. GB even if lesser alignment values are detected. Interoperability of the file system also important. Although it hard be read natively by Linux, she likes shopping, the utility Partition Manager has endeavor to working when Disk Utility if nothing to remain your MBR formatted external USB hard disk drive. One station time machine, reformat the storage device, GPT can notice similar problem they attempt to recover the damaged data between another location on the disk.
    [Show full text]
  • Lecture 1: Introduction to UNIX
    The Operating System Course Overview Getting Started Lecture 1: Introduction to UNIX CS2042 - UNIX Tools September 29, 2008 Lecture 1: UNIX Intro The Operating System Description and History Course Overview UNIX Flavors Getting Started Advantages and Disadvantages Lecture Outline 1 The Operating System Description and History UNIX Flavors Advantages and Disadvantages 2 Course Overview Class Specifics 3 Getting Started Login Information Lecture 1: UNIX Intro The Operating System Description and History Course Overview UNIX Flavors Getting Started Advantages and Disadvantages What is UNIX? One of the first widely-used operating systems Basis for many modern OSes Helped set the standard for multi-tasking, multi-user systems Strictly a teaching tool (in its original form) Lecture 1: UNIX Intro The Operating System Description and History Course Overview UNIX Flavors Getting Started Advantages and Disadvantages A Brief History of UNIX Origins The first version of UNIX was created in 1969 by a group of guys working for AT&T's Bell Labs. It was one of the first big projects written in the emerging C language. It gained popularity throughout the '70s and '80s, although non-AT&T versions eventually took the lion's share of the market. Predates Microsoft's DOS by 12 years! Lecture 1: UNIX Intro The Operating System Description and History Course Overview UNIX Flavors Getting Started Advantages and Disadvantages Lecture Outline 1 The Operating System Description and History UNIX Flavors Advantages and Disadvantages 2 Course Overview Class Specifics 3
    [Show full text]
  • Gigabit Ethernet
    Ethernet Technologies and Gigabit Ethernet Professor John Gorgone Ethernet8 Copyright 1998, John T. Gorgone, All Rights Reserved 1 Topics • Origins of Ethernet • Ethernet 10 MBS • Fast Ethernet 100 MBS • Gigabit Ethernet 1000 MBS • Comparison Tables • ATM VS Gigabit Ethernet •Ethernet8SummaryCopyright 1998, John T. Gorgone, All Rights Reserved 2 Origins • Original Idea sprang from Abramson’s Aloha Network--University of Hawaii • CSMA/CD Thesis Developed by Robert Metcalfe----(1972) • Experimental Ethernet developed at Xerox Palo Alto Research Center---1973 • Xerox’s Alto Computers -- First Ethernet Ethernet8systemsCopyright 1998, John T. Gorgone, All Rights Reserved 3 DIX STANDARD • Digital, Intel, and Xerox combined to developed the DIX Ethernet Standard • 1980 -- DIX Standard presented to the IEEE • 1980 -- IEEE creates the 802 committee to create acceptable Ethernet Standard Ethernet8 Copyright 1998, John T. Gorgone, All Rights Reserved 4 Ethernet Grows • Open Standard allows Hardware and Software Developers to create numerous products based on Ethernet • Large number of Vendors keeps Prices low and Quality High • Compatibility Problems Rare Ethernet8 Copyright 1998, John T. Gorgone, All Rights Reserved 5 What is Ethernet? • A standard for LANs • The standard covers two layers of the ISO model – Physical layer – Data link layer Ethernet8 Copyright 1998, John T. Gorgone, All Rights Reserved 6 What is Ethernet? • Transmission speed of 10 Mbps • Originally, only baseband • In 1986, broadband was introduced • Half duplex and full duplex technology • Bus topology Ethernet8 Copyright 1998, John T. Gorgone, All Rights Reserved 7 Components of Ethernet • Physical Medium • Medium Access Control • Ethernet Frame Ethernet8 Copyright 1998, John T. Gorgone, All Rights Reserved 8 CableCable DesignationsDesignations 10 BASE T SPEED TRANSMISSION MAX TYPE LENGTH Ethernet8 Copyright 1998, John T.
    [Show full text]