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CS145. UNIX OPERATING SYSTEM Lecture 1. OVERVIEW. UNIX Operating System Multi-Tasking Multi-User Interactive Supports computer systems Standalone Networked. HISTORY. Created by Computer Science Research Group at Bell Labs Circa 1970 Objectives of the creators

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CS145

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Cs145

CS145

UNIX

OPERATING

SYSTEM

Lecture 1

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Overview

OVERVIEW

  • UNIX

    • Operating System

      • Multi-Tasking

      • Multi-User

      • Interactive

    • Supports computer systems

      • Standalone

      • Networked

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History

HISTORY

  • Created by

    • Computer Science Research Group at Bell Labs

    • Circa 1970

  • Objectives of the creators

    “... to create a computing environment where they themselves (the staff of CSRG) could comfortably and effectively pursue their own work - programming research.”

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Multi tasking

MULTI-TASKING

  • The ability to perform several tasks -- processes -- at the same time

  • Allows background/foreground processing

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Multi user

MULTI-USER

  • More than one person may use the system at the same time

  • User doing more than one thing at the same time

  • Relatively secure environment for multiple users

  • Multiple protection levels for files, processes

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Interactive

INTERACTIVE

  • User issues commands

  • System performs commands

  • System reports results

  • User issues more commands

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Working in the ctu lab

Working in the CTU Lab

  • Logging in and out

  • Working with the terminal emulator

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Handout terminal emulator

Handout: terminal emulator

  • See separate handout for how to use TerraTerm Pro terminal emulator

  • Emulator simulates a dumb terminal accessing UNIX

  • Handout shows how start, configure emulator

  • Use Windows services for printing – not UNIX print services

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Login name

Login Name

  • Login names

    • Must be at least 6 characters long

    • Only the first 8 characters are significant

    • Case sensitive (as is most of UNIX)

    • Spaces allowed, not recommended

    • Control characters and punctuation are permitted

      • Most people avoid them

      • Control-s and control-g are not permitted

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Login continued

Login continued

  • Best login names contain characters, mixed case, digits

  • Login must exist on the system prior to logging in as that user

  • Login names must be unique

  • Only system admin (Super-User) may issue logon IDs

  • Login entry followed by “Return”

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Login names

Login Names

  • Valid EntriesInvalid Entries

  • cowboy the_black_marauder(> 8 char)

  • marauder john smith(contains a space)

  • johnny sarah^g(contains control-g)

  • johnnyQ sam(too short)

  • cee3po

  • MyLoGiN

  • it’s_me

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Passwords

Passwords

  • Passwords

    • Must be at least 6 characters long

    • Only the first eight characters are significant

    • Case sensitive

    • Spaces, punctuation, and control characters are permitted (but not control-s and control-g)

    • Must be different than login name

    • Must differ from the old password

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Passwords1

Passwords

  • Any user may change their own password

  • Super-User (i.e., systems administrator) cannot decode your password

  • Must be issued a new password if old one forgotten

  • Passwords never appear on the screen

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Passwd command

passwd command

  • $ passwd<cr>

  • system prompts for old password

  • system then prompts for new password

  • system then prompts for new again

  • if change occurs no message appears

    = UNIX Principle: No news is good news

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Login failure

Login Failure

  • A login failure will generate a login error which must be acknowledged

  • If login does not exist

    • Screen will be cleared and a new login screen generated

  • If login does exist, but password is incorrect

    • Only the password entry is cleared

    • The cursor is positioned for a new password attempt.

  • After a certain number of tries, screen is cleared or system quits talking to you

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Login failure cont

Login Failure (cont)

  • Frequently a login will look correct, but is not

    • It may contain a leading space or tab which are difficult to see

  • If login continues to fail after several tries …

    • Contact instructor, then system administrator.

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Successful login

Successful login

  • See the $ prompt – you’re in

  • System ready to accept commands

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Minimizing enlarging windows

Minimizing, enlarging windows

  • Use the Windows screen size controls to maximize, minimize windows

  • DO NOT change window size during a vi editing session

  • You can toggle from the UNIX terminal session to other Windows tools, like Word

  • You can run multiple TerraTerm windows and sessions simultaneously

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  • Login