Task Bar

Class 2/ RAM Memory

RAM (random access memory) is the place in a computer where the operating system, application programs, and data in current use are kept so that they can be quickly reached by the computer's processor. RAM is much faster to read from and write to than the other kinds of storage in a computer, the hard disk, floppy disk, and CD-ROM. However, the data in RAM stays there only as long as your computer is running. When you turn the computer off, RAM loses its data. When you turn your computer on again, your operating system and other files are once again loaded into RAM, usually from your hard disk.

RAM can be compared to a person's short-term memory and the hard disk to the long-term memory. The short-term memory focuses on work at hand, but can only keep so many facts in view at one time. If short-term memory fills up, your brain sometimes is able to refresh it from facts stored in long-term memory. A computer also works this way. If RAM fills up, the processor needs to continually go to the hard disk to overlay old data in RAM with new, slowing

down the computer's operation. Unlike the hard disk which can become completely full of data so that it won't accept any more, RAM never runs out of memory. It keeps operating, but much more slowly than you may want it to.

How Big is RAM?

RAM is small, both in physical size (it's stored in microchips) and in the amount of data it can hold. It's much smaller than your hard disk. A typical computer may come with 256 million bytes of RAM and a hard disk that can hold 40 billion bytes. RAM comes in the form of "discrete" (meaning separate) microchips and also in the form of modules that plug into holes in the computer's motherboard. These holes connect through a bus or set of electrical paths to the processor. The hard drive, on the other hand, stores data on a magnetized surface that looks like a phonograph record.

Most personal computers are designed to allow you to add additional RAM modules up to a certain limit. Having more RAM in your computer reduces the number of times that the computer processor has to read data in from your hard disk, an operation that takes much longer than reading data from RAM. (RAM access time is in nanoseconds; hard disk access time is in milliseconds.)

Now a days, a computer is considered slow if it contains less than one gigabyte.

How to Shut down a computer

Turning off means that Windows closes all open programs and document, logs all users off and then completely turns off your computer. To start your computer again, you will have to press your computer's power button.

Restarting your computer means that computer closes all open programs and documents, logs all users off and then shuts down and starts Windows 7 again, so that you will see Welcome screen again.

Stand by means that computer turns almost all its power off to save battery or energy. This does not mean that computer is completely turned off - all information about the running programs is retained in computer's random access memory (RAM, aka memory, read about Hard disks and Memory here). You can resume from standby by pressing computer's power button once and you will have all your running programs back on your monitor within seconds.

Turning off or restarting Windows 7 computer

To shut down or restart your computer, open Start menu by clicking the Start button or pressing Windows Key (or Ctrl+Esc) on your keyboard. Then click Shut Down:
Windows 7 Start Menu, Shut down button chosen

Windows 7 will not confirm the action, so please be careful clicking the button! After you click Shut down, Windows 7 will immediately close all open programs, log you off and shut down your computer.

If you want to restart your Windows 7 computer, open Start menu and click the right arrow button to the right of the Shut down button. In the list, click Restart.
Windows 7 Start Menu, arrow right button to the right of Shut down button opens a list of other actions. Click Restart if you want to restart your computer.
Turning off or restarting Windows 7 computer without logging on first

You can also turn off or restart your Windows 7 computer when Welcome screen is displayed. Click on the red power button in the right lower corner to shut down your computer immediately:
Windows 7 Welcome Screen, clicking on the red power button shuts down the computer immediately.

If you want to restart, hibernate or put your computer to sleep instead, click the up arrow button to the right of the red power button.
Windows 7 Welcome Screen, click on the up arrow button to the right of the red power button to see other Shut down options, such as Restart, Sleep and Hibernate.

Click on the desired action in the list (this picture does not show Sleep and Hibernate options, but they are available on most modern computers):
Windows 7 Welcome Screen, Shut down options list after clicking on the up arrow button to the right of the red power button. Click on the desired action in the list.

Sometimes the red power button has a yellow shield icon on it and the menu includes an additional command - Install updates and shut down. This command would download all updates available, install them and then turn off your computer.

Class 1/ Operating System

The most important program that runs on a computer. Every general-purpose computer must have an operating system to run other programs. Operating systems perform basic tasks, such as recognizing input from the keyboard, sending output to the display screen, keeping track of files and directories on the disk, and controlling peripheral devices such as disk drives and printers.

For large systems, the operating system has even greater responsibilities and powers. It is like a traffic cop -- it makes sure that different programs and users running at the same time do not interfere with each other. The operating system is also responsible for security, ensuring that unauthorized users do not access the system.

Operating systems provide a software platform on top of which other programs, called application programs, can run. The application programs must be written to run on top of a particular operating system. Your choice of operating system, therefore, determines to a great extent the applications you can run. For PCs, the most popular operating systems are DOS, OS/2, and Windows, but others are available, such as Linux.

As a user, you normally interact with the operating system through a set of commands. For example, the DOS operating system contains commands such as COPY and RENAME for copying files and changing the names of files, respectively. The commands are accepted and executed by a part of the operating system called the command processor or command line interpreter. Graphical user interfaces allow you to enter commands by pointing and clicking at objects that appear on the screen.

A family of operating systems for personal computers. Windows dominates the personal computer world, running, by some estimates, on 90% of all personal computers. The remaining 10% are mostly Macintosh computers. Like the Macintosh operating environment, Windows provides a graphical user interface (GUI), virtual memory management, multitasking, and support for many peripheral devices.

Windows History:

1985 : Windows 1.01
1986 : Windows 1.03
1987 : Windows 2.03
1988 : Windows 2.1
1990 : Windows 3.0
1992 : Windows 3.1
1992 : Windows For Workgroups 3.1
1993 : Microsoft Bob
1993 : Windows NT 3.1
1993 : Windows For Workgroups 3.11
1994 : Windows NT 3.5
1994 : Windows NT 3.51
1995 : Windows 95
1996 : Windows NT 4.0
1998 : Windows 98
2000 : Windows 2000
2000 : Windows ME
2001 : Windows XP
2006 : Windows Vista
2010 : Windows 7

Computer Class Registartion Form

Welcome to the Computer Class

We are really excited to have you as our student. Her at Twin Oaks, we hope that this class is interesting and at the same time useful for you.