An Introduction to Linux

Linux: An Introduction © Anand Vaidya [email_address] Version: 2.2 Last Updated: 20-Jun-2007

Topics What is Linux? UNIX in 2 slides Why use Linux? Why Not Use Linux? Concerns. Who uses Linux & where? Hands on : Demo Hands on : Commands

What is Linux? Comprises of: Monolithic Kernel by Linus Torvalds & many contributors (since 1991) Various GNU, BSD & other software Started as a hobby/learning experiment since Linus found DOS inadequate and UNIX expensive for his i386 machine Modeled after free educational Minix OS Follows UNIX philosophy Source code freely available

Why Linux? Entire OS source code is free (Gratis) – free as in free chocolate Free = Full freedom to study, modify, redistribute. No payments or restrictions. (Libre') – Free as in Freedom Kernel and many packages follow GNU GPL, LGPL or BSD style license. GPL designed to protect end users & programmers rights. Copyrighted to the author, NOT public domain Open Source (http://www.opensource.org) Strong Community around Linux

Why Linux? Powerful command line (shells) Multitasking, SMP, NUMA protected memory True multiuser capabilities Robust journalled filesystem choices:ext3, JFS, XFS, reiserFS Highly modular & scalable: From embedded systems to IBM mainframes (PDA/watch/mobile phone,pc servers, 1024 CPU SGI and IBM mainframes) Multiple hardware architecture: eg: Debian Linux is supported on 11 archs (eg PPC32/64, IA32/64, ARM, SPARC, x86_64, SH etc)

Why Linux? Scales well SMP: 1000+CPU Itanium2 SGI Altix3000 Clusters 4000+ CPU Itanium2 (PNNL), 10000 CPU clusters are in production Support for a wide array of hardware (SCSI, USB, scanners, printers, VGA, RAID, wireless, network hardware, FPGA, InfiniBand, 1/10GE, Myrinet) X11 windowing system for Graphics - optional Various Desktop Environments: KDE, GNOME, Windowmaker, Blackbox etc

Why Linux? Scripting: Shell (bash, csh, zsh, ksh) Perl, Php, Python, Ruby, tcl/tk, lisp.... Several languages: C, C++, pascal Fortran (GNU f77, f90/f95, intel/ pathscale/ pgi f90) Java (sun, blackdown, ibm JREs), GIJ C# (thru Mono, dotGNU) Smalltalk, ada, haskell Rich Development Environment (tools, IDE, code samples, community) kdevelop, anjuta, Eclipse

Why Linux? Server Applications: Web (Apache) DNS (BIND, djbdns) Mail (sendmail, postfix, qmail, pop3, imap) LDAP (OpenLDAP) Database (MySQL, Postgres, Oracle, DB2) Fileserving (NFS, samba, appletalk) Corporate messaging: Lotus Domino, Bynari Insight, Zimbra IM server Source code mgmt: CVS, SVN, DARCS Too many to list...

Why Linux? Scientific Apps: BLAST, bioperl, biopython, biojava... Accelrys DiscoveryStudio, Materials Studio IBM DiscoveryLink CNS, HMMer, Phrep, Phylip, VMD Over 200 opensource BioInformatics apps listed at www.bioinformatics.org

Why Linux? Scientific Apps: Matlab, Mathematica, GNU Octave, R NAMD, AMBER, MM5, Gaussian Fluent (Fluid dynamics), ANSYS CFX Accelrys Materials Studio, CNX Animation, image processing: PRMan, 3dsmax backburner, maya, blender, gimp, filmgimp More...SourceForge lists 100K+ projects (2007)

Why Linux? Virtualization and Grid computing: Linux runs on IBM pSeries, zSeries hypervisor Xen VMM from Cambridge Univ VMWare – WS, GSX, ESX Servers Parallels VM Intel VT and AMD-V hardware virt assists Linux is hot in the Grid computing market (and I would say #1) Other virtualization solutions: OpenVZ, UserMode Linux, etc

Networking Born and brought up on the Internet Very strong networking support: IPv4, Ipv6 Range of networking apps, drivers VPN Firewall (packet-filtering, mangling) Routing, bridging, QoS, VLAN tagging Wireless (routers, embedded) ADSL, SDSL, ATM, SONET, Ethernet, iSCSI High Performance Interconnects: 10Gb Ethernet, Quadrics, Myrinet, Infinband etc Large set of network hardware drivers and protocols

Secure By Design Designed groundup for multiuser, multitasking Strict separation between user and kernel Chroot, jails, Sane defaults Enhancements: NSA SE linux, RSBAC, file ACLs GrSecurity, Openwall, LIDS patches Non exec stack, canary markers (eg Adamantix Debian). No Execute (x86_64) Advanced package management: just install necessary software, no more. run only necessary server programs Extensive logging: almost every activity is logged Easily securable, auditable

CPU support Supports many CPU architectures: x86 Intel IA32 and clones (AMD, Transmeta, Cyrix, VIA etc) IA64 Intel 64bit Itanium2 AMD64 (Opteron and Athlon64) and Intel EM64T IBM PowerPC 32bit PPC970 (Macs), IBM POWER64 Sun Sparc64, Alpha64, MIPS ARM, Hitachi, SuperH,Motorola Coldfire, Intel XScale and many more embedded processor s

Standards Linux and applications adhere closely to various standards and Linux has some of its own: POSIX, ANSI C, various IEEE, ANSI, W3C IETF RFCs (eg mail, web, routing, dns) FHS, LSB, freestandards.org CORBA, SQL... Emblix (embedded linux -japan), CELF, DataCentre Linux LI18N – Internationalisation

Distributions Distributions: =kernel+applications+branding Select, compile and package applications Test ( some thoroughly) Provide Installer (text/GUI) Technical support: phone, email, web Differences in distros: packaging, support, price, supported architectures, target customers

Distributions Popular distributions: Debian (related: Knoppix, (k)ubuntu, Mepis, Xandros) RedHat (related: Fedora, CentOS) SUSE (related: OpenSUSE) Mandriva Slackware Gentoo Embedded Linuxes Other specialised distros: single floppy, NPACI ROCKS, BioBrew, DSL (damn small linux)

Distros-Which One? My Recommendations: Home usage: (user-friendly, mostly GUI, Multimedia rich) Kubuntu (http://www.kubuntu.org) Other choices: OpenSUSE, Fedora Work: RedHat EL or SUSE EL – for vendor support critical apps eg: Oracle, SAP etc. Follow vendor recommendations Debian/Ubuntu or FreeBSD for all fully OSS apps: DNS, Mail, Firewall, NFS/samba, developer desktop, web, ftp servers, mysql,postgres etc... Power user desktops: Let them choose! (Gentoo, Debian/Ubuntu, SUSE, Redhat)

Distros-Which One? My Recommendations: Thin Clients (eg: Libraries, Kiosks etc) LTSP Emergency Rescue, Security work: Choose from one of the several single cd specialised distro. Watch http://freshmeat.net for announcements or searching. Don't forget to study BSD OSes viz. FreeBSD, OpenBSD and netBSD. Each has significant advantages.

UNIX in 2 Slides Been around for 30+ years, Elegant, simple design Dennis Ritchie, Ken Thompson, AT&T Extensively studied, commented and documented UNIX Philosophy (almost) Everything is a file Build small programs: One well defined function and do it very well All programs accept Input from stdin, write to Output:stdout and write Error: stderr Pipes connect program I/O like plumbing, data flows like water Strict separation between privileged (kernel) and user modes. Thompson and Ritchie, the creators of UNIX, working on a PDP-11 machine.

UNIX in 2 slides Commercial UNIXes: SUN Solaris IBM AIX HP UX SGI IRIX Tru64 Many other flavours... ever heard of unicos?

Concerns Hard to install/use - Situation improving Too many distros, incompatible packages-being addressed by standards-LSB, FHS RPM hell – solved by yum, apt, urpmi etc. Availability of popular desktop applications (eg: MS Office, photoshop, Quicken, Games) Hardware - driver availability eg: USB-ADSL modems, winmodems, WinPrinters, VGA adapters etc. Viability of linux vendors & business Model (– Not a major concern nowadays)

Concerns Support : Home / small user: Who will help me? Enterprise: Who will take the blame when there is a problem?

Concerns Immature - compared to UNIXes SMP Scalability not great - compared to UNIX Fear of Code Forking ( hasn't happened in 10+ years, probably won't) Legal issues: GPL not tested in courts, lawyers have questions regarding strength, though situation improving... (eg several German cases, IBM vs SCO) Unknown/hidden Patents, claims by patent trolls Copyrights violations – so far clean Microsoft's vehement, no holds barred effort to destroy Linux & GPL.

Usage: Who & Where Estimate: 55% internet powered by Linux Research/Education: Clusters: NASA, LLNL, LBNL, CERN etc LANL 2048 CPU cluster 9.2TF (nuclear) OSU, MIT, UCB, UCSD... Singapore: BII, NUS, DSI, Library, NTU, SP, NIE, GIS, IMCB, DSO Grid: US Teragrid runs on Linux, Butterfly.net (Gaming on grid) IBM BlueGene (64000 processor, petaflop capability) to run Linux My observation: It is impossible to find a decent organization NOT using Linux

Who & Where Commercial: Korean Air - flight bookings Telstra (Aussie telecom) Petroleum: Shell & others, Veritas Automotive: Crash simulations (Ford, Merc) Financial: Wall St: Schwab,Fidelity Movie animation industry: Pixar, Weta Digital (Nemo, Titanic, Shrek ...) Burlington's coat factory (POS) Central Bank of India 1100 branches. LIC of India -4000+ branches Boeing, Nokia, Sony, Matsushita, NEC, Fujitsu, Motorola Oracle (RAC, ~ 15000 desktops) ISPs for web/mail/ftp Web, mail, file/print – many SMEs: Too numerous.

Users: Who & Where? Desktop: IBM has about 14000 linux desktop users (2003 – Desktop Linux Conference) Planning to go 50-60K) US DoD uses Linux extensively(see Mitre report) Extremadura, Spain 80K desktops in schools Munich, Germany – entire city-14000 desktops Vienna, Austria -entire city Oracle Corp – moving ALL desktop users to Linux ( est. 8000-15000) Enthusiasts – atleast 20 million? Evaluating: Telstra (AU), UK gov, more... First National Bank (SA) – 12000 desktops

Users: Who & Where? EDU: NIE-BioLab (30), RP, SP, NYP (dualboot), NUS (CompSc, DBS, ComCtr, CBE, MPE, ISS, ...), NTU Research: A-STAR (ICES, BII, IMCB, DSI, GIS, I2R, NGP) Commercial: DB, IBM, Several SMEs Gov: NLB Defense: ?? Indiana State (USA)– 22000 students on Linux desktops - Aug2006

FSF & GNU FSF founded by Richard Stallman Started gcc, emacs and GNU project Wrote GPL, LGPL licenses Most of the commercial licenses are designed to take away or restrict user freedom GPL is designed to protect users' freedom ( to examine, modify, share the code. ) Linux depends on GNU software to a large extent. GNU has no working kernel. Depends on Linus for his kernel. GPL allows commercial for-profit use. GPL restricts monopoly rents.

Remember... MS EULA: Sharing is theft, BSD: Sharing is not theft, GPL: Not sharing is theft.

Linux @ Home? Linux @ Home is Real, Feasible ( and FUN too) Homes need very different applications compared to work: ADSL/Phone dialup vs LAN Rich multimedia & Entertainment apps vs limited intranet, client/server Office apps Connectivity to multitude of (cheap) peripherals – colour printers, scanners, mobile phones, PDA, tablets, joysticks etc

Linux @ Home? Security is equally important Direct connection to Internet at home vs professional firewall, IDS & network admins. e-banking, CPF, e-Library, credit card purchases, e-trading accounts Shared usage @ home vs 1 user/desktop at office Kids, grandma, non-IT literate members vs IT-literate workers at the office (-hopefully smart workers? )

Linux @ Home? Why? Free Learn programming, media file manipulation Secure – no trojans, viruses, worms, backdoors, activex Easy to lockdown (kids) Remote login (eg login while travelling, from office) Great Choice of apps Multiuser No need for frequent hardware/software upgrades Recycle old hw to new uses

Linux @ Home? My 2002 home 'network' (fix this slide)

Sample Apps GIMP-Image Editing

Sample Apps Audio player – XMMS mp3/ogg

Sample Apps VCD/DVD Player – mplayer, xine

Sample Apps PDF xpdf, adobe acrobat

Sample Apps Email -kmail, evolution, mozilla-mail

Sample Apps Browsers: konq, mozilla, opera Note the Tabs.

Strange Names Why does Linux have strange application or distribution names? Because Linux truly belongs to the people of the world, linux names are drawn from all over the world. Some are just cheeky abbreviations

Strange Names Ubuntu is an African word, which has been described as "too beautiful to translate into English". The essence of Ubuntu is that "a person is a person through other people". It describes humanity as "being-with-others" and prescribes what "being-with-others" should be all about. Ubuntu emphasises sharing, consensus, and togetherness. Akonadi is KDE's new storage backend, named after the oracle goddess of justice in Ghana. Khalkhi is designed to be the new contacts framework for KDE 4, which happens to be the Georgian word for "people" Program named “less” does more than program named “more”

Links News: http://lwn.net http://www.linuxjournal.com HW compatibility: http://www.linuxcompatible.org Timewasting Discussion: http://slashdot.org Singapore/ASEAN: http://www.lugs.org.sg http://www.asiaosc.org http://www.linux.org http://www.fsf.org http://www.opensource.org

Links Software Listing: http://freshmeat.net http://sf.net Linux Vendors/Projects: http://www.debian.org http://www.kubuntu.org & http://www.ubuntu.com http://fedoraproject.org Commercial: http://www.canonical.com http://www.redhat.com http://www.suse.com http://www.kde.org http://www.gnome.org

Copying or Redistributing © Copyright Anand Vaidya email: vaidya.anand@gmail.com This presentation can be redistributed as follows: No commercial re-distribution: eg, as part of a for-profit CDROM. Seek my permission first. Must attribute the document creator. Share alike: If you use this document and enhance it or modify, share the modifications or the modified document, which means, I apply: http://creativecommons.org/licenses/by-nc-sa/2.5/ license

Thanks! Thanks for your time. If you have any feedback, corrections or questions please contact me: Anand Vaidya, vaidya.anand@gmail.com This document was created with OpenOffice 2.x on Linux

An Introduction to Linux

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