ROOT

1. Alternatively referred to as an admin, administrator, and gatekeeper, root is a superuser on a computer or network and has complete control. See our Administrator definition for a full explanation.

2. The root or root directory is also the highest level in a directory hierarchy. For example, in MS-DOS, the root or root directory of the primary hard drive would C:\. When working on a web page the root directory will be your home directory or your public_html directory.

• MS-DOS help and support.
• Users in the Microsoft recovery console can set the current directory to the system root directory by using the systemroot command.

3. Root is also an ability, effect, or spell in computer games that locks a target in place. For example, in the game World of Warcraft the Mage class has a spell called Frost Nova that freezes an enemy in place for a few seconds.

How much is 1 byte, kilobyte, megabyte, gigabyte, etc.?

Below is a list of each of the accepted disk drive space values. It is important to realize that not all manufacturers and developers use binary base 2. For example, a manufacturer may consider a gigabyte as 1,000,000,000 bytes and not 1,073,741,824 bytes. For this page we are listing all values in their base 2 values.

Note: All values are whole numbers, which means a GB shows it can only contain one 650MB CD, but 1GB could hold 1.5753... of a 650MB CD. Since we created this document to illustrate how much each value can contain in whole, no decimal values are shown. In other words, you can only fit one complete 650MB CD on a 1GB drive since two full 650MB discs exceed 1GB.

Tip: With the exception of a bit and a nibble, all values explained below are in bytes and not bits. For example, a Kilobyte (KB) is different than a Kilobit (Kb). When referring to storage, bytes are used, when referring to transmission speeds bits are used.

Bit

A bit is a value of either a 1 or 0 (on or off).

Nibble

A Nibble is 4 bits.

Byte

Today a Byte is 8 bits.

• 1 character, e.g. "a" is one byte.

Kilobyte (KB)

A Kilobyte is 1,024 bytes.

• 2 or 3 paragraphs of text.

Megabyte (MB)

A Megabyte is 1,048,576 bytes or 1,024 Kilobytes

• 873 pages of plaintext (1,200 characters)
• 4 books (200 pages or 240,000 characters)

Gigabyte (GB)

A Gigabyte is 1,073,741,824 (2³⁰) bytes. 1,024 Megabytes, or 1,048,576 Kilobytes.

• 894,784 pages of plaintext (1,200 characters)
• 4,473 books (200 pages or 240,000 characters)
• 640 web pages (with 1.6MB average file size)
• 341 digital pictures (with 3MB average file size)
• 256 MP3 audio files (with 4MB average file size)
• 1 650MB CD

Terabyte (TB)

A Terabyte is 1,099,511,627,776 (2⁴⁰) bytes, 1,024 Gigabytes, or 1,048,576 Megabytes.

• 916,259,689 pages of plaintext (1,200 characters)
• 4,581,298 books (200 pages or 240,000 characters)
• 655,360 web pages (with 1.6MB average file size)
• 349,525 digital pictures (with 3MB average file size)
• 262,144 MP3 audio files (with 4MB average file size)
• 1,613 650MB CD's
• 233 4.38GB DVD's
• 40 25GB Blu-ray discs

Petabyte (PB)

A Petabyte is 1,125,899,906,842,624 (2⁵⁰) bytes, 1,024 Terabytes, 1,048,576 Gigabytes, or 1,073,741,824 Megabytes.

• 938,249,922,368 pages of plaintext (1,200 characters)
• 4,691,249,611 books (200 pages or 240,000 characters)
• 671,088,640 web pages (with 1.6MB average file size)
• 357,913,941 digital pictures (with 3MB average file size)
• 268,435,456 MP3 audio files (with 4MB average file size)
• 1,651,910 650MB CD's
• 239,400 4.38GB DVD's
• 41,943 25GB Blu-ray discs

Exabyte (EB)

An Exabyte is 1,152,921,504,606,846,976 (2⁶⁰) bytes, 1,024 Petabytes, 1,048,576 Terabytes, 1,073,741,824 Gigabytes, or 1,099,511,627,776 Megabytes.

• 960,767,920,505,705 pages of plaintext (1,200 characters)
• 4,803,839,602,528 books (200 pages or 240,000 characters)
• 687,194,767,360 web pages (with 1.6MB average file size)
• 366,503,875,925 digital pictures (with 3MB average file size)
• 274,877,906,944 MP3 audio files (with 4MB average file size)
• 1,691,556,350 650MB CD's
• 245,146,535 4.38GB DVD's
• 42,949,672 25GB Blu-ray discs

Zettabyte (ZB)

A Zettabyte is 1,180,591,620,717,411,303,424 (2⁷⁰) bytes, 1,024 Exabytes, 1,048,576 Petabytes, 1,073,741,824 Terabytes, 1,099,511,627,776 Gigabytes, or 1,125,899,910,000,000 Megabytes.

• 983,826,350,597,842,752 pages of plaintext (1,200 characters)
• 4,919,131,752,989,213 books (200 pages or 240,000 characters)
• 703,687,443,750,000 web pages (with 1.6MB average file size)
• 375,299,970,000,000 digital pictures (with 3MB average file size)
• 281,474,977,500,000 MP3 audio files (with 4MB average file size)
• 1,732,153,707,691 650MB CD's
• 251,030,052,003 4.38GB DVD's
• 43,980,465,111 25GB Blu-ray discs

Yottabyte (YB)

A Yottabyte is 1,208,925,819,614,629,174,706,176 (2⁸⁰) bytes, 1,024 Zettabytes, 1,048,576 Exabytes, 1,073,741,824 Petabytes, 1,099,511,627,776 Terabytes, 1,125,899,910,000,000 Gigabytes, or 1,152,921,500,000,000,000 Megabytes.

• 1,007,438,183,012,190,978,921 pages of plaintext (1,200 characters)
• 5,037,190,915,060,954,894 books (200 pages or 240,000 characters)
• 720,575,937,500,000,000 web pages (with 1.6MB average file size)
• 384,307,166,666,666,666 digital pictures (with 3MB average file size)
• 288,230,375,000,000,000 MP3 audio files (with 4MB average file size)
• 1,773,725,384,615,384 650MB CD's
• 257,054,773,251,740 4.38GB DVD's
• 45,035,996,273,704 25GB Blu-ray discs

How are you calculating the above values?

To calculate the above values is simple once you know the values of each of the above sizes. For example, in the above example we know that 1 gigabyte is equal to 1,024 Megabytes. Therefore to determine how many 4MB MP3 files are in a Gigabyte, we take 1,024 / 4 which equals 256 or 256 4MB MP3 files in one gigabyte.

software

Sometimes abbreviated as SW and S/W, software is a collection of instructions that enable the user to interact with a computer or have it perform specific tasks for them. Without software, computers would be useless. For example, without your Internet browser software you would be unable to surf the Internet or read this page and without a software operating system the browser would not be able to run on your computer. In the picture is a Microsoft Excel software box and an example of a software program.

How do you get software?

Software can be purchased at a local retail computer store or online, usually in a box that contains all the disks (floppy diskette, CD, DVD, or Blu-ray) required for the program, manuals, warranty, and other necessary documentation.

Software can also be downloaded to a computer over the Internet. Once downloaded, setup files can be run to start the installation of the program on your computer.

Free software

In addition to purchasing software, there are also millions of free software programs available that are broken into different types of categories.

• Shareware or trial software is software that gives you a few days to try the software before you buy the program. After the trial time expires you'll be asked to enter a code or to register the product before you can continue to use it.
• Freeware is completely free software that never requires payment as long as its not modified.
• Open source software is like freeware but not only is the program given away, but the source code used to make the program is as well, allowing anyone to modify the program or view how it was created.

How is software created?

A computer programmer or several computer programmers write the instructions using a programming language that tell the software how to work. Once the program has been completed it is compiled into a language that the computer can understand.

Browser

A software program that allows a person to explore the Internet in an easy to use way. Navigating the Internet through a series of links the user can browse the Internet. Examples of popular browsers are Chrome, Internet Explorer, Firefox, Safari, and Opera. The picture is of the Google Chrome browser and a good example of a browser. Each browser has a navigation toolbar, like the ones shown below that help also illustrate how the Internet browser toolbar has changed over the history of Internet browsers. This navigation bar is the most essential portion of the browser and will always at least contain the Back arrows and address bar.

Overview of browser bar buttons and options

As can be seen by the above picture, over the evolution of the Internet browser the buttons and options have changed. With this in mind, understand that some of the options mentioned below may not be visible in your browser.

Back - Used to visit the previous page that referred you to the page you are currently located at. This button is the button you'll use most while browsing on the Internet and as shown above is a large arrow pointing to the left.

• Why does my Internet back button sometimes not work?
• Creating an HTML back button.

Forward - Like the back button this button moves you forward a page, if you have gone back first. If you have not gone back and your browser shows a forward button, it will be grayed out, as shown above.

• Tip: Hold down the Ctrl key while pressing the left arrow to go back or the right arrow to go forward.

Stop - Stop the loading of a website, this button may need to be used if the page is taking too long to load or encountering problems.

• Tip: Press their esc key at any time to stop loading a page.

Refresh (Reload) - Most Internet browsers cache web pages, so you do not have to download the full page each time you visit the same site. On some pages, you may want to refresh the browser to get the latest version. This button can also be used to reload a page that has been aborted because of an error.

• Tip: Press the F5 key or Ctrl + R to refresh the page from the keyboard.

Home - Go back to your default web page. This is the same page that loads when your browser loads.

• How to change my browser's home page.
• How to make Computer Hope your home page.

Search - Open your default search page or search for text found in the Address or URL text field. Today's browser have a search bar integrated into the search engine and can also use the address bar as a search bar.

Favorites - View or visit a website in your favorites list. The term "Favorites" is used with Microsoft Internet Explorer, in other browsers this may be known as book marks or a hotlist.

Print - Print the page you're visiting. If you don't see a print button, it can also be accessed by clicking on the "File" drop down menu or pressing Ctrl + P on the keyboard.

Font (Size) - Increase or Decrease the size of a font.

• Tip: Holding down the Ctrl key and pressing either the + or - on the top of the keyboard also increases and decreases the font.

Mail - Open your e-mail program.

Edit - Edit the web page you are currently viewing in an HTML editor. Today, no longer found in browsers.

Full Screen - Make the browser window full screen removing all of the toolbars. Often this option is entered and exited by pressing the F11 key on your keyboard.

History - View the history of pages that have been visited since the browser history was last cleared or created.

• Tip: The shortcut key for history for most browsers is Ctrl+H.

Operating system

An operating system or OS is a software program that enables the computer hardware to communicate and operate with the computer software. Without a computer operating system, a computer and software programs would be useless. The picture is an example of Microsoft Windows XP, a popular operating system and what the box may look like if you were to visit a local retail store to purchase it.

When computers were first introduced the user interacted with them using a command line interface, which required the user to perform a series of commands in order to interact with the computer and its hardware and software. Today, almost every computer is using a Graphical User Interface (GUI) operating system that is much easier to use and operate.

Examples of computer operating systems

Microsoft Windows 7 - PC and IBM compatible operating system. Microsoft Windows is the most commonly found and used operating system.
Apple MacOS - Apple computer operating system. The only Apple computer operating system.
Ubuntu Linux - A popular variant of Linux used with PC and IBM compatible computers.
Google Android - operating system used with Android compatible phones.
iOS - Operating system used with the Apple iPhone.

Command Line

Sometimes referred to as the command screen or a text interface, the command line is a user interface that is navigated by typing commands at prompts, as opposed to using the mouse to perform a command. For example, the root MS-DOS command line prompt is C:\> (as shown in the picture) and in Unix or Linux may be % or >. Unlike a GUI operating system, a command line only uses a keyboard to navigate by entering commands and does not utilize a mouse. Because a command line interface requires unique commands, this interface is often more difficult to learn because of the need to memorize dozens of different commands. However, a command line operating system can be a very valuable resource and should not be ignored. For example, users who have Microsoft Windows may find trivial tasks such as renaming 100+ files in a folder a very difficult task; however, this is something that can be done in a matter of seconds through a simple command at the command line.

Text interface with menus

A text interface can be made easier to navigate with menus created with text and extended ASCII extended characters. For example, many command line text editors have some type of interface with menus and shortcut keys that make navigating the file being edited easier. In the example below, is a picture of the MS-DOS Editor used to edit files while at the MS-DOS or Windows command line.

Although a text interface with menus has a lot more visual appeal than the command line, this interface is still considered a text interface and not a graphical interface.

Internet History

Reference	Question
CH001016	Who invented the Internet?

Year	Event
1960	AT&T introduces the dataphone and the first known MODEM.
1961	Leonard Kleinrock publishes his first paper entitled "Information Flow in Large Communication Nets" is published May 31, 1961.
1962	Leonard Kleinrock releases his paper talking about packetization.
1962	Paul Baran suggests transmission of data using fixed size message blocks.
1962	J.C.R. Licklider becomes the first Director of IPTO and gives his vision of a galactic network.
1964	Baran publishes reports "On Distributed Communications."
1964	Leonard Kleinrock publishes his first book on packet nets entitled Communication Nets: Stochastic Message Flow and Design.
1965	Lawrence G. Roberts with MIT performs the first long distant dial-up connection between a TX-2 computer in Massachusetts and Tom Marill with a Q-32 at SDC in California.
1965	Donald Davies coins the word "Packet."
1966	Lawrence G. Roberts and Tom Marill publish a paper about their earlier success at connecting over dial-up.
1966	Robert Taylor joins ARPA and brings Larry Roberts there to develop ARPANET.
1967	Donald Davies creates 1-node NPL packet net.
1967	Wes Clark suggests use of a minicomputer for network packet switch.
1968	Doug Engelbart publicly demonstrates Hypertext on December 9, 1968.
1968	The first Network Working Group (NWG) meeting is held.
1968	Larry Roberts publishes ARPANET program plan on June 3, 1968.
1968	First RFP for a network goes out.
1968	UCLA is selected to be the first node on the Internet as we know it today and serve as the Network Msmnt Center.
1969	Steve Crocker releases RFC #1 on April 7, 1979 introducing the Host-to-Host and talking about the IMP software.
1969	UCLA puts out a press release introducing the public to the Internet on July 3, 1969.
1969	On August 29, 1969 the first network switch and the first piece of network equipment (called "IMP", which is short for Interface Message Processor) is sent to UCLA.
1969	On September 2, 1969 the first data moves from UCLA host to the IMP switch.
1969	CompuServe, the first commercial online service, is established.
1970	Steve Crocker and UCLA team releases NCP.
1971	Ray Tomlinson sends the first e-mail, the first messaging system to send messages across a network to other users.
1972	First public demo of ARPANET.
1972	Norm Abramson' Alohanet connected to ARPANET: packet radio nets.
1973	Vinton Cerf and Robert Kahn design TCP during 1973 and later publish it with the help of Yogen Dalal and Carl Sunshine in December of 1974 in RFC 675.
1973	ARPA deploys SATNET the first international connection.
1973	Robert Metcalfe creates the Ethernet at the Xerox Palo Alto Research Center (PARC).
1973	The first VoIP call is made.
1974	A commercial version of ARPANET known as Telenet is introduced and considered by many to be the first Internet Service Provider (ISP).
1978	TCP splits into TCP/IP driven by Danny Cohen, David Reed, and John Shoch to support real-time traffic. This allows the creation of UDP.
1978	John Shoch and Jon Hupp at Xerox PARC develop the first worm.
1981	BITNET is founded.
1983	ARPANET standardizes TCP/IP.
1984	Paul Mockapetris and Jon Postel introduce DNS.
1986	Eric Thomas develops the first Listserv.
1986	NSFNET is created.
1986	BITNET II is created.
1988	First T-1 backbone is added to ARPANET.
1988	Bitnet and CSNET merge to create CREN.
1990	ARPANET replaced by NSFNET.
1990	The first search engine Archie, written by Alan Emtage, Bill Heelan, and Mike Parker at McGill University in Montreal Canada is released on September 10, 1990
1991	Tim Berners-Lee introduces WWW to the public on August 6, 1991.
1991	NSF opens the Internet to commercial use.
1992	Internet Society formed.
1992	NSFNET upgraded to T-3 backbone.
1993	The White House and the United Nations come online in 1993 and help start the .gov and .org top level domains.
1993	The NCSA releases the Mosaic browser.
1994	Netscape (Mosaic Communications corporation) is found by Marc Andreessen and James H. Clark April 4, 1994.
1994	Mosaic Netscape 0.9, the first Netscape browser is officially released October 13, 1994. This browser also introduces the Internet to Cookies.
1994	WXYC (89.3 FM Chapel Hill, NC USA) becomes first traditional radio station to announce broadcasting on the Internet November 7, 1994.
1994	Tim Berners-Lee establishes and heads the W3C in October 1994.
1995	The dot-com boom starts.
1995	The SSL protocol is developed and introduced by Netscape in February 1995.
1995	On April 1, 1995 the Opera browser is released.
1995	The first VoIP software (Vocaltec) is released allowing end users to make voice calls over the Internet.
1995	On August 16, 1995 Microsoft introduces and releases Microsoft Internet Explorer.
1995	On November 24, 1995 HTML 2.0 is introduced in RFC 1866.
1995	On December 4, 1995 Sun Microsystems announced JavaScript and first releases it in Netscape 2.0B3. In the same year they also introduced Java.
1996	Telecom Act deregulates data networks.
1996	Now known as Adobe Flash, Macromedia Flash is introduced in 1996.
1996	The first CSS specification, CSS 1, is published by the W3C in December 1996.
1996	More e-mail is sent than postal mail in USA.
1996	CREN ended its support and since then the network has cease to exist.
1997	Internet2 consortium is established.
1997	IEEE releases 802.11 (WiFi) standard.
1998	Internet weblogs begin to appear.
1998	XML becomes a W3C recommendation February 10, 1998.
1999	Napster starts sharing files in September of 1999.
1999	On December 1, 1999 the most expensive Internet domain name business.com was sold by Marc Ostrofsky for $7.5 Million The domain was later sold on July 26, 2007 again to R.H. Donnelley for $345 Million USD.
2000	The dot-com bubble starts to burst.
2003	January 7, 2003 CREN's members decided to dissolve the organization.
2003	On June 30, 2003 the Safari browser is released.
2004	On November 9, 2004 Mozilla releases the Mozilla Firefox browser.
2008	On December 11, 2008 the Google Chrome.