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CS145

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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  1. CS145 UNIX OPERATING SYSTEM Lecture 1 CS 145

  2. OVERVIEW • UNIX • Operating System • Multi-Tasking • Multi-User • Interactive • Supports computer systems • Standalone • Networked CS 145

  3. 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.” CS 145

  4. MULTI-TASKING • The ability to perform several tasks -- processes -- at the same time • Allows background/foreground processing CS 145

  5. 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 CS 145

  6. INTERACTIVE • User issues commands • System performs commands • System reports results • User issues more commands CS 145

  7. Working in the CTU Lab • Logging in and out • Working with the terminal emulator CS 145

  8. 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 CS 145

  9. 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 CS 145

  10. 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” CS 145

  11. 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 CS 145

  12. 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 CS 145

  13. 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 CS 145

  14. 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 CS 145

  15. 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 CS 145

  16. 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. CS 145

  17. Successful login • See the $ prompt – you’re in • System ready to accept commands CS 145

  18. 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 CS 145

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