ICS124 UNIX Operating System and Seneca Network Environment

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ICS124 - UNIX Operating System and Seneca Network
Environment
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Computer Networks

• Personal computers that are not connected to
  other computers (via network cards) are referred
  to as stand-alone computers.
• Institutions such as colleges find it more
  economical and efficient to connect up personal
  computers to form a computer network

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Computer Network
File Server(Central Computer)
Terminal(Client)
Terminal(Client)
Terminal(Client)
Terminal(Client)
Terminal(Client)
Terminal(Client)
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File Server

• A file server is a powerful centralized computer
  system with an operating system that allows
  multiple users to access software applications
  and data files.
• The file server may also provide other important
  services such as network printer management and
  connection to other networks (Internet)

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Computer Networks

• Computers connected to form a network over small
  geographic locations (such as a building or city)
  are referred to as Local Area Networks (LANs)
• Local Area Networks can use modems or routers to
  connect up to other LANs from far distances to
  form Wide Area Networks (WANs)

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Advantages of Computer Networks

• Economical
• Ability to share hardware devices such as
  printers and scanners
• Efficient
• Ability to communicate among users
• Efficient method to maintain and upgrade software
  (I.e. one copy of software on file server -
  therefore, only upgrade one location)
• Ability for users to share files

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Seneca Computer Network

• Newnham Campus

LEARNMERCURYILEARN
NewnhamCampus
T1
S_at_Y
Modem Pool
T1
Internet
T1
Don Mills Campus
Remote Users
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Seneca Computer Network
PHOBOS (RS6000)VISION PANDORA
CS CS1
POSEIDON COMPSTUD (Novell)
ZEUS (AS400) ODIN (AS400)JUPITER SNOW WHITE
(Linux)
Newnham Campus
T1
Don MillsCampus
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Seneca Computer Network
Columbus (FCE Students)
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Relevant Servers

• PHOBOS
• Computer account used for creating, modifying,
  compiling and executing programs - AIX UNIX
• (IBM RS6000 - See ICS124 Notes for details)
• ODIN
• Computer account used for access to the AS/400.
• COLUMBUS
• Used to store and maintain WebPages for FCE
  students.

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Introduction to UNIX

• UNIX is the most popular operating system. Most
  large computers use UNIX as their operating
  system
• UNIX is a TEXT BASED system.

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What is an Operating System

• Control program for a computer
• OS handles - communications between the
  application software and the computer hardware.
• Memory protection - system accounting
• smooth operation ? - Response Time

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Bit of UNIX History

• MULTICS first interactive multi-user OS developed
  by Bell labs.
• Ken Thompson 1969 at ATT Bell Laboratories. -
  UNIX
• UNIX a pun on MULTICS not an acronym
• Given almost for free to Universities and
  Colleges to obtain a following into the business
  world.

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Bit of UNIX History

• Generic version follows System V Release 4, with
  companies as Sun (Solaris), Hewlett Packard(HP)
  and IBM altering it to suit their customer base.
• Linux - LinusTorvalds

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Overview of UNIX File Structure
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Directories

• The directory of a disk is an area where the
  names and locations of files are stored.
• Each storage device such as a hard disk has at
  least one directory which is called Root.
• Directories make it more efficient to store files
  under logical categories or locations.

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Directories

• Inverted Tree Diagrams visualize directory
  structures

Root ( / )
Students is theparent directory of msaul
tmp
students
msaul
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Making Directories

• Building directories is similar in approach to
  building a house
• Begins from a foundation (root)
• Need to build in proper order (add on addition to
  house in right location)
• Need to step-back and look at construction

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Overview UNIX Shell

• Pg. 11 of the Sobell text
• shell is the interface between the operating
  system and the user.- interprets instructions
• calls the program you want
• can also program the shell - script writing.

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Limitations of UNIX ?

• Called terse, unfriendly difficult to learn.
• No news is good news. Gives more flexibility to
  programmer - confirmation of activity being
  completed is not given. Result more powerful -
  can string a succession of instructions together
  and they will be performed.

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Basic Unix Commands

• Case sensitive
• Flags
• A flag is a letter or letters added to a command
  to indicate
• an option (see next slide for example)
• Flags are what make UNIX so powerful

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MAN

• MAN is the online manual. Once you can log in,
  MAN will help you do everything else
• man ls (will provide details on how the ls
  command works, its options and how to call them.
• The -k flag means keyword (allowing you to obtain
  on commands that match the keyword).
• man password
• man -k password

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List Files

• ls Displays compact list of files (excluding
• hidden files - beginning with period)
• ls -a Displays all files (including hidden
  files)
• ls -l Displays detailed list of files (excluding
• hidden files)
• ls -al Displays all files in detail form
  (including
• hidden files)

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Additional Unix Commands

• Interrupt
• Stop output
• Resume output
• logout
• Delete character / word / line

• Ctrl C (c)
• Ctrl S
• Ctrl Q
• Ctrl D
• Ctrl H, W, U

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Additional Unix Commands

• Pwd
• cd /tmp
• cd

• Displays current directory
• Changes to tmp directory
• Changes to home directory

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Additional Unix Commands

• Find commands to
• delete a file
• change the permissions of a file
• Create a folder
• Find out who is logged in
• show processes running
• display a file on the screen

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Changing Directories

• cd directory
• cd directory path
• cd
• cd .. (change to parent directory)

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How to Logon to PHOBOS Server

• Run Telnet Program
• Type in your Login I.D.
• Type in your password

NOTE UNIX is case sensitive. Upper and Lower
case letters are recognized as different by UNIX.
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What is the Telnet Application?

• Unix systems such as PHOBOS were originally
  designed to accommodate dumb terminals which
  were simply monitors and keyboards directly
  connected up to network
• Telnet allows the server to think that the
  users personal computer is a dumb terminal
• A common type of dumb terminal was Digital
  Equipment corporations VT100.

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Telnet Application

• To launch or run the Telnet application from
  the Seneca computing lab, point and click onto
  the application terminal on the Windows 95
  desktop
• You can obtain a free version of Telnet
  application for home use from the internet
  (assuming you have computer system with modem).

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Protecting your Computer Accounts

• It is important to assign an appropriate password
  to prevent unauthorized access to your computer
  accounts.
• Concerns regarding unauthorized use
• Illegal Activity
• Suspension of account
• Loss of data / Copying of assignments

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Changing your Password

• After logging onto PHOBOS, you can change your
  password by typing at the prompt
• passwd ltENTERgt
• Note It is recommended to change password
  periodically.

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Password Tips

• Combine upper and lower case letters
• Include a non alpha-numeric characters such as .
  - in your password
• Acceptable passwords on PHOBOS range from 6 to 8
  characters

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Password Tips

• Avoid easily detected passwords such as
• names
• birth dates
• addresses
• patterns
• year and month

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Password tips

• Use phrases and take the first letter of each
  word For example
• Autumn leaves Turn red, yellow, orange ALTRYO
• Add numbers and characters to words
• R1o2N3!

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For Review - Basic Unix Commands

• Listing Files
• ls Displays compact list of files (excluding
• hidden files - beginning with period)
• ls -a Displays all files (including hidden
  files)
• ls -l Displays detailed list of files (excluding
• hidden files)
• ls -al Displays all files in detail form
  (including
• hidden files)

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Additional Unix Commands

• Commands
• pwd Displays current directory
• cd /tmp Changes to tmp directory
• cd Changes to default directory
• man Online manual

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For next week.

• Create an acceptable password using the
  above-mentioned techniques.
• Read over RS600/nled documentation and vi
  information.