Chapter Ten Networking with UNIX. Brief History of UNIX System V (1960’s) Versions of UNIX that come from Bell Labs Versions of UNIX that come from Bell.

Chapter TenChapter TenNetworkingNetworking

with UNIXwith UNIX

Brief History of UNIXBrief History of UNIX

System V (1960’s)System V (1960’s) Versions of UNIX that come from Bell LabsVersions of UNIX that come from Bell Labs Antitrust law prohibited saleAntitrust law prohibited sale

BSD (Berkeley Software Division)BSD (Berkeley Software Division) Versions of UNIX from researchers at the University of Versions of UNIX from researchers at the University of

California at BerkeleyCalifornia at Berkeley Added TCP/IPAdded TCP/IP

Caldera International and Tarantella jointly own the Caldera International and Tarantella jointly own the rights to the UNIX rights to the UNIX source codesource code

The Open Group owns the UNIX trademarkThe Open Group owns the UNIX trademark

Common UNIX FeaturesCommon UNIX Features

The ability to support The ability to support multiple, simultaneously multiple, simultaneously logged in userslogged in users

Hierarchical file systemsHierarchical file systems that incorporate that incorporate demountable volumesdemountable volumes

Consistent interfacesConsistent interfaces for input of data to and for input of data to and output of data from hardware devices, files, output of data from hardware devices, files, and running programsand running programs

The ability to start processes in the The ability to start processes in the backgroundbackground

Common UNIX FeaturesCommon UNIX Features

Hundreds of subsystems, including Hundreds of subsystems, including dozens of programming languagesdozens of programming languages

Program Program source code portabilitysource code portability

Windows interfaces that the user can Windows interfaces that the user can configure, the most popular of which is the configure, the most popular of which is the X WindowX Window system system

Current State of the MarketCurrent State of the Market

Unix market is Unix market is hugehuge and and highly segmentedhighly segmented

Some Some real-timereal-time implementations of the implementations of the UNIX system existUNIX system exist In a real-time implementation, the operating In a real-time implementation, the operating

system must respond to input immediatelysystem must respond to input immediately NASA – space shuttle & international space NASA – space shuttle & international space

stationstation

Two major UNIX market segmentsTwo major UNIX market segments ProprietaryProprietary Open sourceOpen source

Proprietary UNIXProprietary UNIX

An implementation of UNIX for which the An implementation of UNIX for which the source code is either unavailablesource code is either unavailable or or available available only by purchasingonly by purchasing a licensed a licensed copy from Caldera International and copy from Caldera International and TarantellaTarantella Sun’s proprietary version of UNIX is called Sun’s proprietary version of UNIX is called

Solaris Solaris (for SPARC-based workstations)(for SPARC-based workstations) IBM’s proprietary version of UNIX is called IBM’s proprietary version of UNIX is called AIXAIX HP’s proprietary version of UNIX is called HP’s proprietary version of UNIX is called HP-HP-

UXUX

Choosing a Proprietary UNIX SystemChoosing a Proprietary UNIX System

AdvantagesAdvantages Accountability and supportAccountability and support Optimization of hardware and softwareOptimization of hardware and software Predictability and compatibilityPredictability and compatibility

DrawbackDrawback Customer has no access to the system’s Customer has no access to the system’s

source code and thus cannot create a custom source code and thus cannot create a custom solutionsolution

Open Source UNIXOpen Source UNIX

Open source softwareOpen source software Software developed and packaged by a Software developed and packaged by a

few individuals and made available to few individuals and made available to anyone without licensing feesanyone without licensing fees

Also called Also called freely distributed softwarefreely distributed softwareUNIX-like systems in this category include UNIX-like systems in this category include GNU, FreeBSD, and LinuxGNU, FreeBSD, and Linux

Different implementations of UNIX-like Different implementations of UNIX-like systems are known as systems are known as flavorsflavors

Linux – RedHat, Caldera, & MandrakeLinux – RedHat, Caldera, & Mandrake

Open Source UNIXOpen Source UNIX

Freely distributable versions of UNIX Freely distributable versions of UNIX include a copyright called the include a copyright called the General General Public LicensePublic License (requires the source code (requires the source code to be made available to anyone receiving to be made available to anyone receiving the system)the system)

1991 - Linus Torvalds (then a 21991 - Linus Torvalds (then a 2ndnd year year Finnish computer science student) Finnish computer science student) developed Linuxdeveloped Linux

Choosing UNIXChoosing UNIX

UNIX supports TCP/IP, IPX/SPX and UNIX supports TCP/IP, IPX/SPX and AppleTalk protocolsAppleTalk protocols

UNIX supports Ethernet, Token Ring, UNIX supports Ethernet, Token Ring, FDDI and wireless LANsFDDI and wireless LANs

Choosing UNIXChoosing UNIX

SambaSamba Open source software packageOpen source software package Complete Windows 2000-style file and print sharing Complete Windows 2000-style file and print sharing

facilityfacility

UNIX was originally developed as a UNIX was originally developed as a time-sharing time-sharing systemsystem Computing system to which Computing system to which each user must attach each user must attach

directlydirectly to share the resources of that computer (dumb to share the resources of that computer (dumb terminal)terminal)

Some proprietary UNIX systems have received Some proprietary UNIX systems have received Orange BookOrange Book certification certification U.S. DOD certificationU.S. DOD certification

UNIX Server HardwareUNIX Server Hardware

Base system unit must include:Base system unit must include: Motherboard with CPU, memory, and I/O Motherboard with CPU, memory, and I/O

controlcontrol Network interface card (NIC)Network interface card (NIC) Floppy disk driveFloppy disk drive CD-ROM driveCD-ROM drive One or more fixed disksOne or more fixed disks

Decisions in Choosing Decisions in Choosing HardwareHardware

Table 10-1: Typical

hardware requirements for a Linux

server

A Closer Look at LinuxA Closer Look at Linux

Linux multiprocessingLinux multiprocessing Supports symmetric multiprocessing (SMP)Supports symmetric multiprocessing (SMP)

Linux memory modelLinux memory model From its inception, Linux was created to use From its inception, Linux was created to use

both physical and virtual memory efficientlyboth physical and virtual memory efficiently

Linux KernelLinux Kernel

KernelKernel As in NetWare, is the core of the systemAs in NetWare, is the core of the system Also similar to NetWare, it is possible to add Also similar to NetWare, it is possible to add

or remove functionality by loading and or remove functionality by loading and unloading Linux unloading Linux kernel moduleskernel modules

Similar to NetWare NLMsSimilar to NetWare NLMs

Linux File and Directory Linux File and Directory StructureStructure

Hierarchical file systemHierarchical file system Organization of files and directories on a disk partition in which Organization of files and directories on a disk partition in which

directories may contain files and directoriesdirectories may contain files and directories

FIGURE 10-1 Linux file

system hierarchy

Linux File ServicesLinux File Services

Linux includes support for multiple types of file Linux includes support for multiple types of file systems, including:systems, including: Local file systemsLocal file systems Remote file systems – map to Windows or NetWare Remote file systems – map to Windows or NetWare

ServersServers

Its native file system, called ext2 (second extended)Its native file system, called ext2 (second extended) Can access FAT & NTFS (read-only) file systemsCan access FAT & NTFS (read-only) file systems Sun Microsystem’s Network File System (NFS)Sun Microsystem’s Network File System (NFS)

Linux Internet ServicesLinux Internet Servicesand Linux Processesand Linux Processes

Linux Internet ServicesLinux Internet Services First browsers and servers were developed on First browsers and servers were developed on

UNIXUNIX ApacheApache

Open source software application that is the Open source software application that is the leadingleading Internet Web server Internet Web server

Linux ProcessesLinux Processes Another UNIX innovation is the notion of Another UNIX innovation is the notion of

separate, numbered processesseparate, numbered processes

Linux Command SamplerLinux Command Sampler

Command interpreterCommand interpreter Program that accepts your typing and runs Program that accepts your typing and runs

the commandthe command Also known as a Also known as a shellshell Keeps track of the command history, much Keeps track of the command history, much

like the like the doskeydoskey command in DOS and command in DOS and Windows 2000Windows 2000

Linux Command SamplerLinux Command Sampler

GlobbingGlobbing Form of filename substitutionForm of filename substitution Similar to using wildcards in Windows/DOSSimilar to using wildcards in Windows/DOS

PipePipe Serves as the connection between two Serves as the connection between two

commandscommands

PipelinePipeline Two or more commands separated by a pipeTwo or more commands separated by a pipe

Linux Command SamplerLinux Command Sampler

TABLE 10-2a: Commonly used Linux commands

(p. 493)

Linux Command SamplerLinux Command Sampler

TABLE 10-2b: Commonly used Linux commands

(cont.)

Linux Command SamplerLinux Command Sampler

Linux systems keep quite a bit of information Linux systems keep quite a bit of information about each file, including:about each file, including: FilenameFilename File size (in bytes)File size (in bytes) Date and time a file’s Date and time a file’s i-nodei-node (file information (file information

node) was creatednode) was created Date and time that the file was last accessedDate and time that the file was last accessed Date and time that the file contents were last Date and time that the file contents were last

modifiedmodified

Linux Command SamplerLinux Command Sampler

Information Linux system keeps about each Information Linux system keeps about each file (cont.):file (cont.): Number of “aliases” or links to the fileNumber of “aliases” or links to the file Numeric identifier of the user who owns the fileNumeric identifier of the user who owns the file Numeric identifier of the group to which the file Numeric identifier of the group to which the file

belongsbelongs Access rights for the owner, the group, and all Access rights for the owner, the group, and all

othersothers

Linux Command SamplerLinux Command Sampler

To learn about the i-node information, use the ls commandTo learn about the i-node information, use the ls command

Figure 10-2: Example of output from ls

Linux Preinstallation QuestionsLinux Preinstallation Questions

Linux very peacefully coexists with other Linux very peacefully coexists with other operating systems on your primary hard driveoperating systems on your primary hard drive

Read more about multiboot systems at the Read more about multiboot systems at the Linux installation Linux installation HOWTOHOWTO site: site: http://www.linuxhq.com/ldp/howto/Installation-HOhttp://www.linuxhq.com/ldp/howto/Installation-HO

WTO/index.htmlWTO/index.html

Internetworking with Other Network Internetworking with Other Network Operating SystemsOperating Systems

Samba – Windows file & printer sharingSamba – Windows file & printer sharing

IPX/SPXIPX/SPX

AppleTalkAppleTalk

X3270 – mainframe accessX3270 – mainframe access

WINE – Win32 programming subsystemWINE – Win32 programming subsystem

VMWare – emulate Intel-based computerVMWare – emulate Intel-based computer

Dozens and dozens of command-line utilities Dozens and dozens of command-line utilities that enable access to contents of files generated that enable access to contents of files generated on other systemson other systems