outline

Historical Perspective

• Prior to the 1950's, computers such as ENIAC (Electronic Numerical Integrator and Computer), had no operating system
  -many people were required to manually connect wires and set switches so the program could run

PCs (Personal Computers)

• 1969 - UNIX was developed by Bell Labs, a research facility for AT&T
• 1981 - IBM began selling the PC and MS-DOS (Microsoft Disk Operating System) was selected as the standard for the system
• 1983 - Apple introduced the first publicly available computer using a GUI (graphical user interface) - the Apple Lisa
• 1984 - Apple released the Macintosh
• DOS did not embrace the GUI approach until the advent of Windows

Operating Systems

• Controls the input, output and process activities for a computer
• Acts as a traffic cop to control the resources of the computer
  - computer memory
  - file storage space
  - the computer processor (CPU)

Operating System

• Is a software program that helps the user interact with the computer
• Helps the all the hardware components communicate with each other
• Acts as a Box of Tools
  -utility programs allow you to move files, create directories, copy files, etc.
• Is a self-starter - "booting"

Command Lines

• The Operating System gives you an interface C:\> indicates a command line interface
• DOS and UNIX are both command line operating systems

GUIs

• Graphical User Interface
• Has nice pictures with descriptive words underneath
• Allows you to 'click' with the mouse to start a program and other computer tasks
• Picture concepts are easier to understand
  - "A picture is worth a 1,000 words"
• Without the pictures you would have to know the exact command required to move a file instead of clicking and dragging with the mouse

Examples of Operating Systems

• DOS
• UNIX
• Windows 3.1
• Windows 95 and 98
• Mac System 7.0

Problems Operating Systems are Good at Solving

• Organization
• An interface you can interact with efficiently
• Helps all parts of your system to communicate with each other

The "Tree"

• Think of the file structure of an operating system like a "tree"
• 

The Root

• A general starting point on each drive
• 

Directories

• Next level after root directory
• Programs usually install their own directory
• 

Subdirectories

• Next level after Directories
• There may be several levels of subdirectories before you get to the files.

Files

• May be considered an organized collection of computer information
• Are stored on the computer with the help of the operating system
• Each operating system has its own convention for naming files

Operating Tools from the Operating System

• User Interface
  -command line
  -GUI
• Management tools to help you manage your files

Multitasking

• The ability to run more than one program at a time
• Active program is the one currently getting your attention
• Any program that is visible is "open", but may not be the active program

File Management Programs

• A utility of the Operating System
• Things you can find in a file manager program
  - indicator of the current drive
  - a way to change drives
  - a picture of the tree structure
  - an indicator of the current directory
  - a list of subdirectories on the current directory
  - a way to change directories
  - list of files on the current directory
  - and a way to back up to the previous directory

Common File Management Programs

• File Manager (Windows 3.1)
• Explorer (Windows 95)
• My Computer (Windows 95/98)
• The Mac Desktop (Macintosh)
• File management in a command line system

Problem Solving with File Management Systems

• Organizing your disk
  - directory, subdirectories, files
• Finding where things are located
• Manipulating files - copying, deleting, etc.
• Manipulating directories - making new ones and naming them

Tools File Management Programs Give You

• Visual Representation of directory structure
• Drag and drop features
• Graphic representation of files and directories
• Menus and toolbars (file and directory manipulation tools)

Symbolic Representation Schemes

• Common programs
  - Program Manager (Windows 3.1)
  - Start button (Windows 95/98)
  - Desktop (Windows 95/98)
  - Apple Menu (Mac System 7+)

Problems Symbolic Schemes are Good at Solving

• A custom file system
• Virtual files, Virtual Directories