Operating System basics by Anirban Basu

Operating system and concepts:

Operating system and concepts Anirban Basu Modern Institute of Engineering and Technology ,Bandel

OBJECTIVES:

OBJECTIVES By the end of this lecture you should … Understand the role of operating systems in computer science Understand the basic concepts of DOS and Linux . Basic overview of Linux and DOS Commands

Windows XP:

Windows XP

OPERATING SYSTEM OVERVIEW :

OPERATING SYSTEM OVERVIEW WHAT IS AN OPERATING SYSTEM? An interface between users and hardware. Allows convenient usage; hides the tedious stuff. Allows efficient usage; parallel activity, avoids wasted resources. Provides information protection Gives each user a slice of the resources Acts as a control program.

OPERATING SYSTEM OVERVIEW:

OPERATING SYSTEM OVERVIEW

OPERATING SYSTEM OVERVIEW :

OPERATING SYSTEM OVERVIEW A mechanism for scheduling jobs or processes. Scheduling can be as simple as running the next process, or it can use relatively complex rules to pick a running process. A method for simultaneous CPU execution and IO handling. Processing is going on even as IO is occurring in preparation for future CPU work. Off Line Processing; not only are IO and CPU happening concurrently, but some off-board processing is occurring with the IO.

MS DOS:

MS DOS A non-graphical command line operating system . Tasks are performed with the keyboard rather than the mouse. A “directory” in DOS is the same as a “folder” in Windows terms.

DOS Prompt:

DOS Prompt

INTERNAL DOS COMMAND:

INTERNAL DOS COMMAND Command Syntax Function TYPE TYPE [drive:][path]filename Edit Files COPY COPY [source] [destination] Copy one or more file to alternate location. DEL DEL [drive:][path]filename To delete files CD CD [drive:][path] To change Directory MD MD [drive:]path To Make(create) Directory RD RD [drive:]path To Remove Directory CLS CLS Clears Screen DIR DIR[drive:][path] List all files of a given directory

Slide 10:

COPYCON COPY CON[file name] To create a file with specified name REN REN [drive:][path][directoryname1 | filename1] [directoryname2 | filename2] To rename a file/directory TIME TIME [time] To display/set the system time DATE DATE [date] To  display/set the system date VER VER To display the version of DOS VOL VOL [drive:] To display the volume information about designated drive PROMPT PROMPT [text] To change the command prompt by the text specified PATH PATH To display the current path

ELEMENTARY EXTERNAL DOS COMMANDS:

ELEMENTARY EXTERNAL DOS COMMANDS Batch Files : Batch Files consists of collection of DOS commands, batched together in one file. Extension  of Batch files : .BAT Steps of creating batch files(Example) : Open an MS-DOS command window. At the MS-DOS prompt, type: edit test.bat and press enter. If typed properly, you should now be in a blue screen. Within the screen, type: pause dir c:\windows dir c:\windows\system

DOS :

DOS 4. Once the above three lines have been typed in, save file and exit. 5. Once you are back at the MS-DOS prompt, type: test and press enter. This will execute the test.bat file and begin running the file. Because the first line is pause, you will first be prompted to press a key. Once you press a key the batch file will run line-by-line; in this case, listing the files in the windows and windows\system directories. Simply type "edit test.bat" to edit the file again.

INTRODUCTION TO WINDOWS:

INTRODUCTION TO WINDOWS History : Basic development of the Windows operating system from 1990 to 2007 is as follows: Windows 3.1 : Year - 1990,1992,1993,1994 Windows 95 : Year - 1995,1996,1997 Windows 98 : Year - 1998,1999 Windows ME : Year - 2000 Windows XP : Year – 2001 to 2006 Windows Vista : Year – 2007 till now..

Windows 98:

Windows 98

Windows 3.1:

Windows 3.1

What Is UNIX?:

A computer operating system. It is designed to be used by many people at the same time (multi-user). Runs on a variety of processors Lends itself well to use in scientific research What Is UNIX?

Snapshot of a LINUX System:

Snapshot of a LINUX System

Linux terminal:

Linux terminal

History:

History UNIX was invented in 1969 at AT&T Bell Labs Ken Thompson and Dennis Ritchie are credited as the original architects Written in the C language in 1973 Version of AIX on blueice is based on System V UNIX Different Flavors, All UNIX: Solaris (Sun), AIX (IBM), Linux (open source), Irix (SGI), Berkeley (Mac OS X based on this)

Files and Directories:

Files and Directories UNIX uses a hierarchy to store files Using a UNIX means working with a command line, which is much like working from a DOS prompt. Linux lets you multitask (run more than one command at a time) Files are simply a named collection of bytes Directories contain other files

Basic Directory Terms:

Basic Directory Terms • Home directory - top of your file tree • Root directory - top of a file tree • Current directory - directory you’re in now • Dot (.) - slang for the current directory • Dot-dot (..) - parent of the current directory • Path - Where to find file or directory Absolute path: / fs / scd /home0/ juliana / myfile Relative path: ~/ myfile • Wildcard - * (asterisk) stands for any character

Managing Files and Directories:

Managing Files and Directories mkdir - creates a directory rmdir - removes a directory (must be empty first) rm - fr - removes directory and everything below touch <filename> - creates an empty file cat <filename> - displays a file on screen more <filename> - to see a screenful at a time • mv myfile1 myfile2 - renames a file (and moves it)

OPERATING SYSTEM OVERVIEW :

OPERATING SYSTEM OVERVIEW We’ve completed our first overview of an Operating System – this was the equivalent of a Satellite picture. Recommended References: Silberschatz , Galvin , Gagne: Operating System Concepts Your Unix , 2nd Edition. Sumitabha