ITSC 1329 Module 1

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ITSC 1329 Module 1

• Using the Desktop in the Solaris 10 Operating
  System

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Module 1 Objectives

• Define the purpose of an OS
• Describe the UNIX Philosophy
• Describe the hardware components of a computer
• Describe the Solaris OS components
• Describe the importance of /etc/passwd
• List the seven fields of /etc/passwd
• List the password requirements for Solaris
• List differences between CDE and Telnet access

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Purpose of an Operating System
An OS is a set of programs and files that directs
and controls both the hardware and software of a
computer.

• Hardware Components
• CD-Rom
• Hard drive
• Monitor
• Keyboard
• Printer
• CPU
• Memory

• Application Software
• Word Processing
• Spreadsheets
• Internet Browsers
• Games
• Databases
• Utilities
• Graphics

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Brief History of UNIX

• Created by ATT Bell Lab in late 1960s
• Designed as a tool for programmers
• Early source code was released to the public
• UC Berkeley developed BSD-UNIX
• First multi-tasking, multi-threading,
  multi-processing, multi-user network OS
• TCP/IP was developed for use with UNIX

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UNIX Philosophy

• Simple and independent commands
• No file types (extensions)
• Commands designed to work with other commands
  through piping
• Distrust all claims for One true way
• Design for the future, it will be here sooner
  than you think
• http//www.faqs.org/docs/artu/ch01s06.html

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Computer Hardware Components

• Processor (CPU)
• Memory (RAM)
• Input / Output
• Storage

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Three main components of an OS

• Kernel
• Shell
• Directory Hierarchy (File System)

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The Kernel

• The kernel is the core of the SunOS. It is
  responsible for managing all the physical
  resources of the computer, including
• File systems and structures
• Device, process and memory management
• Includes swap space allocation
• Manages Daemons
• A daemon is a process that performs a specific
  system task. Services perform this function in
  Windows systems.

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The Shell

• Acts as the interface between the user and the
  kernel
• Interprets commands entered by the user and
  passes them to the kernel where they are executed
• There are a variety of shells available for use
  with the UNIX OS

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Three primary shells used by Solaris

• Bourne shell
• C shell
• Korn shell

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Bourne Shell

• Original UNIX shell
• Default Solaris shell
• Default shell for the root user
• Default prompt
• Default prompt for root user
• Key in sh at command prompt to invoke the Bourne
  shell

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C Shell

• Features not included with Bourne shell
• Command line history
• Aliasing
• Job control
• Default prompt (hostname)
• Default prompt for root user (hostname)
• Key in csh at command prompt to invoke the C shell

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Korn Shell

• Superset of the Bourne shell
• C shell-like enhancements
• Command line history
• Aliasing
• Job control
• Command line editing
• Default prompt
• Default prompt for root user
• Scripts written in the Bourne shell can be run in
  the Korn shell
• Key in ksh at command prompt to invoke the Korn
  shell

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Directory Hierarchy (File System)

• The UNIX file system is used by the OS to
  organize and keep track of files
• Called hierarchical because files and directories
  are organized in a top-down tree structure

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Got Root?

• The top of the UNIX file system is the root
  directory
• The root directory is always represented by the
  forward slash /
• Required for the operating system to function and
  contains critical system files
• Not to be confused with the root user account!

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Important UNIX Directories

• /usr - contains the bin subdirectory that
  contains executable commands and utilities, and
  the lib subdirectory that contains system library
  routines
• /opt - contains unbundled and third-party
  software applications (optional application
  programs)
• /dev - contains logical device names for physical
  device drivers to access input/output devices on
  the system

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Important UNIX Directories Continued

• /kernel contains kernel files for the local
  platform architecture contains the genunix file
  which is the UNIX kernel for the system
• /export - typically contains directories exported
  using NFS
• /export/home - contains users home directories
• /etc - contains system administration files such
  as the passwd and hosts files

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The /etc/passwd file

• The passwd file is located in the /etc directory
• Used by the UNIX OS to authenticate users
• Maps usernames to UIDs
• Each line in /etc/passwd represents a user
  account
• Each line contains seven fields delimited by a
  colon

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The Seven fields of /etc/passwd
A typical entry in /etc/passwd looks something
like this jsmithx1091100John
Smith/export/home/jsmith/bin/ksh

• Username represents the users login name.
  This field is restricted to eight characters in
  length and only the first letter may be an
  uppercase character.
• Placeholder represented by an X - this field is
  a placeholder for the users encrypted password,
  which is stored in the /etc/shadow file.

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The Seven fields of /etc/passwd
jsmithx1091100John Smith/export/home/jsmith/
bin/ksh

• UID contains the User Identification number
  that is used by the operating system to identify
  the user. Numbers usually range from 100 to
  60,000
• GID contains the group identification number
  that is used by the system to identity the users
  primary group

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The Seven fields of /etc/passwd
jsmithx1091100John Smith/export/home/jsmith/
bin/ksh

• Comment usually contains the users full name.
  Can NOT contain a colon!
• Login-directory known as the users home
  directory is a file system space reserved for the
  users storage area. Usually located under the
  /export/home subdirectory
• Default shell defines the users default login
  shell

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Password Requirements

• Six to Eight characters in length
• Contain at least two alphabetic characters and
  must contain at least one numeric or special
  character, such as a semicolon (), an asterisk
  (), or a dollar sign ()
• Differ from the users login name
• Differ from previous password by three characters

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Password Requirements (continued)

• Can not be the reverse of the login name
• May contain spaces (optional)
• Does NOT apply to the root user account, or any
  account created by the root user

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The Nine fields of /etc/shadow

• Login Name Matches the corresponding name in
  the /etc/passwd file
• Encrypted Password
• Password Change Date when the password was last
  changed
• Minimum Change Days minimum number of days that
  must pass before the user is allowed to change
  password again
• Maximum Valid Days maximum days before user if
  forced to change password

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Fields of /etc/shadow (continued)

• Number of Warning Days number of days before
  password expires will start to warn user
• Number of Inactive Days number of days of
  inactivity the user is allowed
• Expiry Date the date the account will expire.
  It is shown as the number of days from January 1,
  1970.
• Not used reserved for future use

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The four fields of /etc/group

• Name Specifies a Group Name that is unique to
  the system. The name is a string of 8 bytes or
  less.
• Password Not used. Group Administrators are
  provided instead group passwords.
• Group Id Specifies the group id. The value is a
  unique decimal integer.
• User1, ...,Usern Identifies a list of one or
  more users. Separate names with commas.

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/etc/group (continued)

• Typical /etc/group file layout
• NamePasswordIDUser1,User2,...,Usern
• You should access the /etc/group file through the
  system commands and subroutines defined for this
  purpose. You can use the following commands to
  manage groups
• chgroup

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• chgrpmem
• rmgroup
• chuser
• lsgroup
• mkgroup
• mkuser

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The Solaris Desktop vs. Telnet

• Solaris Desktop
• CDE (Common Desktop Environment)
• GUI interface
• Remote desktop to the CDE available from other
  Solaris machines
• Access to command-line through CDE

• Telnet Access
• Command-line
• Information is sent in clear text format
• Secure Shell Access
• Command-line
• Information uses public key cryptography

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Module 1 Objectives Review

• Define the purpose of an OS
• Describe the UNIX Philosophy
• Describe the hardware components of a computer
• Describe the Solaris OS components
• Describe the importance of /etc/passwd
• List the seven fields of /etc/passwd
• List the nine fields of /etc/shadow
• List the password requirements for Solaris
• List differences between CDE and Telnet access