Digital Data vs. Analog Data

• Digital data is 0's and 1's, everything is represented by 0's and 1's.
• Analog data is represented by a wave , normal phone lines use a wave signal such as this to represent your voice as you talk on the phone.
• The 0's and the 1's can be copied exactly use the following example to see why digital data is much better than analog
• with a pencil copy the wave above on to a piece of paper
• now right below it copy the wave you just created, and then below that copy the last wave you created .
• Now compare your last wave with the wave above, it would be very suprising if they look anything alike.
• Now copy the series of 0's and 1's - 010100001
• No matter how many times you copy the string of 0's and 1's it will look the exact same.
• This is why digital data is almost as good as the real thing.

Computer only use Digital Data, all the data in a computer is digital.

Booting up the computer

First things you should know are the three main components of the computer I will be discussing today.

1. First is the Processor, or sometimes called CPU (central processing unit)this is the brains of the computer, all the calculations and instructions you computer executes is done in the processor.
2. Next is the Harddrive - this is the central source of storage on your computer, the memory is non-volatile which means even if the power is turned off you don't lose any information in the memory. The harddrive is for storage of all your programs and operating system. The processor can not read directly from the Harddrive first the informatinon on the harddrive must be moved to the next type of memory RAM.
3. Next is RAM (Random Access Memory) - RAM is volatile memory that is much faster than the harddrive. Volatile memory means that when the power is turned off the items in RAM are lost. The significance of RAM is that any instructions of a program that the processor must execute must be moved into RAM from the harddrive or CD or some other type of storage device before the processor can execute the instruction.

Now the steps of what happens when you turn on your computer

• Before you turn on your computer all the programs, including the operating system are stored on your harddrive (non-volatile).
• When you turn on the computer a small chip of memory, called ROM (Read-Only-Memory), boots up the computer(ROM is a little chip that just holds a few instructions for booting up your computer).
• "Boot-up" is the slang for getting the computer ready for use by a user.
• The ROM knows where to look for the Operating System. Before the ROM chip looks on the harddrive for the operating system the default instructions from the factory tell the computer to first look in the floppy drive for an operating system (this way if your harddrive breaks you can still boot up off a floppy disk that has an operating system on it). If no operating system. is found in the floppy drive then the ROM chip tells the computer to look at a predefined memory location (factory defined location) on the Harddrive. If the computer is configured correctly at the factory the Operating System is found and loaded from the hardrive into RAM so the processor can then use the instructions of the Operating System to run the computer.
• Key things to know about RAM:
• RAM stands for Random Access Memory.
• RAM loses all information stored on it when the computer is turned off. (Volatile)
• Everything that is new, or never been saved on the harddrive must be saved to harddrive before turning off the computer or it will be lost.
• Anything viewed on the screen or used by the processor must be loaded into RAM first.
• So ROM goes to harddrive then loads the Operating System into RAM so it can viewed and used by the user, you.

Terminology

This is a quick list of terms you'll see and use a lot. If you haven't yet, you should access the Terms of Endearment Web page
that has many more terms you'll need to become familiar with. You can access the Terms through the main Computer Literacy
Web page. The lab manual tells you how.

Icons - visual representation of items - little pictures on your screen
Dragging - moving items with the aid of the mouse pointer
Menus - itemized list of available commands
Dialog box - tell computer what you want it to do
Cursor - the little arrow on your screen that is controlled by moving the mouse on your desk
Clicking - once on the left mouse button
Right clicking - once on the right mouse button
Double clicking - twice on the left mouse button

Software VS Hardware

The difference between Hardware and Software is Hardware can be physically touched. If you can reach out and touch something on the computer it would be considered Hardware. Like the following:

• Hardware -
• RAM
• ROM
• CPU - The brains of the computer, all instructions a computer executes are executed by the processor. The faster the processor at executing instructions the faster your computer is.

Software on the other hand are things that run on the computer, they can't be touched, they can just be viewed or run.

• Software
• Programs

• System Software
• Application Software (Netscape, Word, Excel).

Operating Systems (Windows XP)

Operating Systems

The software that controls the execution of all applications and system software programs.

Operating System Names:

• Windows XP (Microsoft)
• Unix
• OS/2 (IBM)
• Macintosh System (Unix based)
• Etc, etc. Many, Many others on the market.

Types of Operating Systems

• Single program/singer user - (Windows 3.1) (no longer around..too old)
• Multitasking - Can allow many users or programs to operate at the same time with only one CPU. (Windows 95)
• Multiprocessing - Many users, many CPU's (Unix)

The job of an Operating System

• Communicater - communicates between user and computer.
• File management - Acts as a file cabinet, organizing the contents of the computer.
• Handles the disk directory (Front desk of a motel, it has a master key to all the rooms and who is sleeping in them.)
• Maintains the File Allocation Table. (A large index of the software and files in the computer).
• Provides a user interface.
• GUI - Graphical User Interface -  a combination of icons(pictures) that represent various programs and files, and a mouse to point and click to items you want to use.
• Character based (DOS) - No pictures, or windows just text. You have to have all the instructions memorized. Clicking on an windows based icon would be equivalent to typing 'run icon name'.
• Manages computer resources
• The Cpu (multitasking)-If more than one program is running the operating system controls hands out time slices of the hardware resources to all programs running.
• Memory management

HARDDRIVE VS RAM

Before explaining what happens when turning on your computer you need to understand the differences between RAM and the Harddrive. Both are types of memory.

• Harddrive is for long term storing of data, programs, and files. When the computer is turned off the harddrive doesn't lose any of the information stored there. Floppy drives/disks have the same characteristics they just can't hold as much stuff, but they are transportable.
• RAM (Random Access Memory) is Volatile, this means if you turn off the computer all the information in RAM is lost, poof, gone. So before you turn off your computer make sure anything you are working on is saved on the harddrive or floppy drive.

The reason you need both is speed. RAM is almost as fast as the speed of light. harddrives aren't very fast comparitively speaking. The
 

BOOTING UP (A reminder look)

When you first turn on your computer the operating System is stored on the Harddrive. The ROM memory boots up the computer, it tells the CPU where to check for the operating system. The first place it looks is the floppy drive (that way you can override the harddrive if there is a problem). If there isn't a disk in the floppy drive it then looks at the Harddrive. These default settings can be changed in the BIOS setup, but don't.
 

Windows O.S. essentials

• The Desk Top
• Task Bar
• Icons
• Start

• Folders
• Used to be called directories
• Defined as an organized collection of objects
• Can contain files or other folders
• Hierarchical structure
• Files
• Defined as a collection of data
• Can be a program or a data document
• Stored in a folder on a drive
• Icon usaully represent an application
• File names
• Names can be up to 256 characters (used to be 8)
• Spaces are allowed in names
• Case sensitive
• File extensions are automatic

'My Computer' Icon

• Reflects the hardware connected to that computer
• Will show contents of a particular folder
• Each folder will show a different folder
• Can be confusing, matching subfolders to folders