1. D O S Disk Operating System

2. What is an Operating System? • A set of programs (called commands) that tell the computer how to make all its hardware work • It is always running in the background, no matter what task you are using your computer for at any given time

3. An Operating System… • Recognizes messages (input) coming from the keyboard or mouse • Sends messages (output) to the video screen or the printer • Controls any additional devices (printers, modems, etc) you have attached to your computer    

4. Major Components of Any OS • Input/Output Interface • What the user sees and interacts with • Text based or graphical user interface (GUI) icons • File Management System • Organizes program files • Command Processor • Works with program files and is the core of the operating system  A-M

5. DOS – Disk Operating System • DOS can refer to any operating system, but most often used to mean MS-DOS • Originally developed by Microsoft for IBM in the early 1980’s and became the standard operating system for the PC world • Before using your computer, DOS needs to be up and running

6. DOS Input/Output Interface • Text based • Commands are entered by typing combinations of letters and symbols on a command line • Example: C:\>copy a: c: • Does not use icons or the mouse  

7. _ MS-DOS Prompt  X  Auto A Microsoft ® Windows 98 © Copyright Microsoft Corp. 1981-1998. C:\> DOS Prompt Screen C = Designates the disk drive being accessed. \ = Represents a level in the hierarchy of the file structure > = Symbolizes the prompt itself

8. _ MS-DOS Prompt  X  Auto A Microsoft ® Windows 98 © Copyright Microsoft Corp. 1981-1998. C:\>dir C:\>md DOSCLASS C:\>cd DOSCLASS C:\DOSCLASS>cd .. C:\>rd DOSCLASS Basic DOS Directory Commands • Views the contents of the root directory • Makes a new directory called DOSCLASS • Changes to the DOSCLASS directory • Changes the directory back to the previous one. Notice how the prompt changes when you change the directory • Removes the DOSCLASS directory. All files in the directory must be removed before removing the directory.

9. _ MS-DOS Prompt  X  Auto A Microsoft ® Windows 98 © Copyright Microsoft Corp. 1981-1998. C:\>ren list.wp mylist.wp C:\>copy animals.doc dogs.doc C:\>copy animals.doc a: C:\>del a:\animals.doc C:\>type animals.doc Basic DOS File Commands • Changes a file name from list to mylist • Duplicate a file, commonly done to create a backup copy of your original file • Creates an exact copy of the animal file on a different disk • Deletes the animal file • Displays a file on the computer screen so you can read it

10. DOS File Names • All filenames must follow a pattern • Up to 8 characters in the descriptive part • Followed by a “.” with up to three more characters referred to as the extension. • Example: animal.doc • File names can be entered in upper or lowercase letters • You cannot use the following characters in a filename • . / \ [ ] * < > = , ; : “ | + ?

11. Common File Extensions • TXT ---------------- A text file • EXE ---------------- An executable file • SYS ---------------- A system file • COM --------------- A command program • BAT ---------------- A batch file

12. DOS to Windows • Many people find typing commands too technical • Windows created with icons to make file management easier • DOS is needed to run in the background of Windows • Newer operating systems, such as Windows NT, do not rely on DOS, although they can execute DOS-based programs. • It is expected that as the newer operating systems gain market share, DOS will eventually disappear.

13. DOS Web Sites Resources • www.pcwebopaedia.com/disk_operating_system.htm • w3.ag.uiuc.edu/AIM/CCSOcourses/DOS-rev.html • www.computerhope.com/msdos.htm