Computer and Internet Terms
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Hacker

While this term originally referred to a clever or expert programmer, it is now more commonly used to refer to someone who can gain unauthorized access to other computers. A hacker can "hack" his or her way through the security levels of a computer system or network. This can be as simple as figuring out somebody else's password or as complex as writing a custom program to break another computer's security software. Hackers are the reason software manufacturers release periodic "security updates" to their programs. While it is unlikely that the average person will get "hacked," some large businesses and organizations receive multiple hacking attempts a day.



Hard Copy

A hard copy is a printed document. It may be a text file, photograph, drawing, or any other type of printable file. For example, instead of e-mailing a business memo, it may be sent out as a hard copy, or an actual physical paper containing the memo.

When a document is created on a computer, it is typically saved as a file on the the computer's hard drive. This is sometimes referred to as a soft copy. While the file can be easily opened and edited on a computer, it can also be easily deleted. Therefore, sometimes printing a hard copy is done to create a physical backup of the document.



Hard Disk

When you save data or install programs on your computer, the information is typically written to your hard disk. The hard disk is a spindle of magnetic disks, called platters, that record and store information. Because the data is stored magnetically, information recorded to the hard disk remains intact after you turn your computer off. This is an important distinction between the hard disk and RAM, or memory, which is reset when the computer's power is turned off.



The hard disk is housed inside the hard drive, which reads and writes data to the disk. The hard drive also transmits data back and forth between the CPU and the disk. When you save data on your hard disk, the hard drive has to write thousands, if not millions, of ones and zeros to the hard disk. It is an amazing process to think about, but may also be a good incentive to keep a backup of your data.



Hard Token

A hard token, sometimes called an "authentication token," is a hardware security device that is used to authorize a user. An common example of a hard token is a security card that gives a user access to different areas of building or allows him to log in to a computer system. Some hard tokens are used in combination with other security measures to further enhance security. For example, a username and password or a fingerprint scan may be required along with the hard token to gain access to a secure system.

A hard tag is another type of hard token that is used as a security device on merchandise such as clothing and electronics. You have probably seen these used in several retail stores, where they are used to deter theft. If someone tries to exit the building with merchandise before the hard tag has been deactivated, it causes the security system by the doors to beep. Of course, if the cashier forgets to deactivate the hard tag, you get to experience the unpleasant beeping sound as you exit even if you paid for the merchandise.



Hardware

Computer hardware refers to the physical parts of a computer and related devices. Internal hardware devices include motherboards, hard drives, and RAM. External hardware devices include monitors, keyboards, mice, printers, and scanners.

The internal hardware parts of a computer are often referred to as components, while external hardware devices are usually called peripherals. Together, they all fall under the category of computer hardware. Software, on the other hand, consists of the programs and applications that run on computers. Because software runs on computer hardware, software programs often have system requirements that list the minimum hardware required for the software to run.



HDMI

Stands for "High-Definition Multimedia Interface." HDMI is a digital interface for transmitting audio and video data in a single cable. It is supported by most HDTVs and related components, such as DVD and Blu-ray players, cable boxes, and video game systems.

While other types of A/V connections require separate cables for audio and video data, HDMI carries the audio and video streams together, greatly eliminating cable clutter. For example, a component cable connection requires three cables for video and two for audio, totaling five cables in all. The same information can be transmitted using one HDMI cable.

Because HDMI is a digital connection, HDMI cables are less prone to interference and signal noise than analog cables. Also, since most components, such as DVD players and digital cable boxes process information digitally, using HDMI eliminates the analog to digital conversion other interfaces require. Therefore, HDMI often produces the best quality picture and sound compared to other types of connections.

HDMI cables are typically more expensive than analog cables, largely because they cost more to manufacture. But it is important to remember that with HDMI, you don't need to buy separate audio and video cables. Besides, the single all-purpose connection may alone be worth the difference to those who don't like dealing with confusing cables and connections. Just remember that before you buy an HDMI cable, make sure the devices you are connecting have HDMI connections available.



HDTV

Stands for "High Definition Televsion." HDTV is a high-quality video standard developed to replace older video formats often referred to as SDTV (standard definition television). While HDTV's video quality is one of the most noticeable improvements over SDTV, HDTV includes a number of other important improvements as well.



First of all, the HDTV signal is digital. Instead of an analog signal, used by traditional NTSC broadcasts, HDTV is always digital. This eliminates analog interference caused be electrical currents and magnetic fields. Secondly, HDTV uses a different aspect ratio than SDTV. While previous broadcasts used a 4:3 ratio (4 units wide for every 3 units tall), HDTV uses a ratio of 16:9. This wider aspect ratio more closely emulates how humans see the world, making the image appear more realistic. This ratio is also better for watching widescreen movies, which are recorded in widescreen for the same reason.

True to its name, high definition television offers a much higher resolution than standard definition video. While a typical analog broadcast in the U.S. contains a maximum of 525 horizontal lines of resolution, an HDTV signal supports up to 1080. The three formats used by HDTV are 1080i (interlaced), and 720p and 1080p (progressive). HDTV's higher resolution produces images that are much finer and contain more detail and more color than previous formats. HDTV also provides a higher-quality digital audio signal than SDTV and supports up to six audio channels compared to the two channels allowed previously.

To watch HDTV, you need an HDTV-compatible television and a means of receiving an HDTV signal. HDTVs come in both 16:9 and 4:3 formats (for backwards compatibility). Some HDTVs include HDTV tuners for receiving over-the-air broadcasts, but others require the receiver to be bought separately. Fortunately, most cable and satellite TV companies offer HDTV-compatible boxes with their digital service plans.



HDV

Stands for "High-Definition Video." According to a consortium of manufacturers including Sony, JVC, Canon, and Sharp, it is a "consumer high-definition video format." HDV is the next step up from Mini DV, which has been used in consumer digital camcorders for several years. The HDV technology allows high-definition video to be recorded on a Mini DV tape, using MPEG-2 compression.

Of course, recording in high-definition requires an HD camcorder, such as the Sony HDR-FX1 or the JVC GR-HD1. These cameras are significantly more expensive than their Mini DV counterparts, but can capture much higher quality video. HDV uses a native 16:9 widescreen format, with a resolution of 1280 x 720 pixels. This is a substantial improvement over Mini DV, which records video in a 4:3 format, with a maximum resolution of 500 horizontal lines. Most HDV camcorders allow the user to record in standard DV as well, but if you shell out a couple thousand dollars extra for a HDV camcorder, you might as well shoot everything in HD.



Hertz

Hertz (abbreviated: Hz) is the standard unit of measurement used for measuring frequency. Since frequency is measured in cycles per second, one hertz equals one cycle per second.

Hertz is used commonly used to measure wave frequencies, such as sound waves, light waves, and radio waves. For example, the average human ear can detect sound waves between 20 and 20,000 Hz. Sound waves close to 20 Hz have a low pitch and are called "bass" frequencies. Sound waves above 5,000 Hz have a high pitch and are called "treble" frequencies.

While hertz can be used to measure wave frequencies, it is also used to measure the speed of computer processors. For example, each CPU is rated at a specific clock speed. This number indicates how many instruction cycles the processor can perform each second. Since modern processors can perform millions or even billions of instructions per second, clock speeds are typically measured in megahertz or gigahertz.



Heuristic

Generally speaking, a heuristic is a "rule of thumb," or a good guide to follow when making decisions. In computer science, a heuristic has a similar meaning, but refers specifically to algorithms.

When programming software, computer programmers aim to create the most efficient algorithms to accomplish various tasks. These may include simple processes like sorting numbers or complex functions such as processing images or video clips. Since these functions often accept a wide range of input, one algorithm may perform well in certain cases, while not very well in others.

For example, the GIF image compression algorithm performs well on small images with few colors, but not as well as JPEG compression on large images with many colors. If you knew you were only going to be dealing with small images that didn't have a wide range of colors, GIF compression would be all you need. You wouldn't have to worry about large, colorful images, so there would be no point in optimizing the algorithm for those images. Similarly, computer programmers often use algorithms that work well for most situations, even though they may perform inefficiently for uncommon situations.

Therefore, a heuristic process may include running tests and getting results by trial and error. As more sample data is tested, it becomes easier to create an efficient algorithm to process similar types of data. As stated previously, these algorithms are not always perfect, but work well most of the time. The goal of heuristics is to develop a simple process that generates accurate results in an acceptable amount of time.



Hexadecimal

Hexadecimal is a base-16 number system. It is a different method of representing numbers than the base-10 system we use in every day practice. In base-10, we count in multiples of 10 before adding another digit. For example, "8 - 9 - 10 - 11 - 12..." and "98 - 99 - 100 - 101 - 102..." Notice how a new digit is added when the number 10 is reached, and another digit is added to represent 100 (10x10). In base-16, or the hexadecimal number system, each digit can have sixteen values instead of ten.



While computers process numbers using the base-2, or binary system, it is often more efficient to visually represent the numbers in hexadecimal format. This is because it only takes one hexadecimal digit to represent four binary digits. Since there are eight binary digits in a byte, only two hexadecimal digits are needed to represent one byte.



Hibernate

If you are not going to use your computer for a few hours, it is a good idea to put it to sleep (also known as standby mode) to save power. If you are not going to use the computer for more than a day, it is usually best to turn it off. However, some Windows computer offer an option that combines the benefits of sleep mode and powering down the computer, called "Hibernate."

When you select Hibernate, the computer saves the current state of the system from the computer's RAM to the hard disk, then shuts down. When the computer is restarted, instead of going through the typical boot sequence, the previously saved state is automatically loaded into the RAM. The open windows and running programs from your previous session appear just as they were when the computer entered Hibernate mode. Basically, Hibernate mode acts like Standby mode, except the computer can be completely turned off. This is especially helpful for laptop computers, which will slowly lose their battery charge if they are left in sleep mode.

To make your computer hibernate, select "Turn Off Computer" from the bottom of the Windows Start Menu. Then press and hold the Shift key when the dialog box appears. The "Standby" option should change to "Hibernate." If the Standby option does not change, you may need to enable Hibernate mode in Windows. This can be done by opening the "Power Options" control panel, clicking the Hibernate tab, and checking the box that says, "Enable hibernation."



Hit

Technically, a hit is a request made to a Web server. It is a popular misconception that the term refers to the number of visits a Web page gets, but that is not the case. If a Web page has five images on it, when the page is loaded, six "hits" will be recorded. This is because the browser has to make six requests to the Web server - one for the HTML of the Web page and five for the images.

The term "hit" can also be used to refer to search engine results. When you search for a phrase and the search engine finds 510 results, you can say there were 510 hits and be happy because you used the term correctly.



Home Page

This is the starting point or front page of a Web site. This page usually has some sort of table of contents on it and often describes the purpose of the site. For example, http://www.apple.com/index.html is the home page of Apple.com. When you type in a basic URL, such as "http://www.cnet.com," you are typically directed to the home page of the Web site. Many people have a "personal home page," which is another way the term "home page" can be used.



Host

This is a computer that acts as a server for other computers on a network. It can be a Web server, an e-mail server, an FTP server, etc. For example, a Web host is what provides the content of Web pages to the computers that access it. A host is also known as the mother computer. Well, not really, I just made that up.



Hover

When you roll the cursor over a link on a Web page, it is often referred to as "hovering" over the link. This is somewhat like when your boss hovers over you at work, but not nearly as uncomfortable. In most cases, the cursor will change from a pointer to a small hand when it is hovering over a link. Web developers can also use cascading style sheets (CSS) to modify the color and style of link when a user hovers over it. For example, the link may become underlined or change color while the cursor is hovering over it.

The term hovering implies your computer screen is a three-dimensional space. In this conception, your cursor moves around on a layer above the text and images. When you click the mouse button while the cursor is hovering over a link, it presses down on the link to activate it. Hovering can also be used in a more general sense such as moving the cursor over icons, windows, or other objects on the screen.



HTML

Stands for "Hyper-Text Markup Language." This is the language that Web pages are written in. Also known as hypertext documents, Web pages must conform to the rules of HTML in order to be displayed correctly in a Web browser. The HTML syntax is based on a list of tags that describe the page's format and what is displayed on the Web page.

Fortunately, the HTML language is relatively easy to learn. Even more fortunately (so much for good grammar), many Web development programs allow you to create Web pages using a graphical interface. These programs allow you to place objects and text on the page and the HTML code is written for you.



HTTP

Stands for "HyperText Transfer Protocol." This is the protocol used to transfer data over the World Wide Web. That's why all Web site addresses begin with "http://". Whenever you type a URL into your browser and hit Enter, your computer sends an HTTP request to the appropriate Web server. The Web server, which is designed to handle HTTP requests, then sends to you the requested HTML page.



HTTPS

Stands for "HyperText Transport Protocol Secure." HTTPS is the same thing as HTTP, but uses a secure socket layer (SSL) for security purposes. Some examples of sites that use HTTPS include banking and investment websites, e-commerce websites, and most websites that require you to log in.

Websites that use the standard HTTP protocol transmit and receive data in an unsecured manner. This means it is possible for someone to eavesdrop on the data being transferred between the user and the Web server. While this is highly unlikely, it is not a comforting thought that someone might be capturing your credit card number or other personal information that you enter on a website. Therefore, secure websites use the HTTPS protocol to encrypt the data being sent back and forth with SSL encryption. If someone were to capture the data being transferred via HTTPS, it would be unrecognizable.

You can tell if a website is secure by viewing the URL in the address field of your Web browser. If the Web address starts with https://, you know you are accessing a secure website. Most browsers will also display a lock icon somewhere along the edge of the window to indicate the website you are currently visiting is secure. You can click the lock icon to view the secure certificate that authenticates the website.

So whenever you are asked to enter personal or financial information on a website, make sure that the URL starts with "https://" and that the lock icon appears in the window. Then you can be sure that the website is secure and any data you enter will only be recognized by your computer and the Web server.



Hub

This is a hardware device that is used to network multiple computers together. It is a central connection for all the computers in a network, which is usually Ethernet-based. Information sent to the hub can flow to any other computer on the network. If you need to connect more than two computers together, a hub will allow you to do so. If you only need to network two computers together, a simple crossover Ethernet cable will do the trick.





Hyper-Threading

Hyper-threading is a technology developed by Intel Corporation. It is used in certain Pentium 4 processors and all Intel Xeon processors. Hyper-threading technology, commonly referred to as "HT Technology," enables the processor to execute two threads, or sets of instructions, at the same time. Since hyper-threading allows two streams to be executed in parallel, it is almost like having two separate processors working together.

While hyper-threading can improve processing performance, software must support multiple processors to take advantage of the technology. Fortunately, recent versions of both Windows and Linux support multiple processors and therefore benefit from hyper-threading. For example, a video playing in Windows Media Player should not be slowed down by a Web page loading in Internet Explorer. Hyper-threading allows the two programs to be processed as separate threads at the same time. However, individual programs can only take advantage of Intel's HT Technology if they have been programmed to support multiple processors.



Hyperlink

A hyperlink is a word, phrase, or image that you can click on to jump to a new document or a new section within the current document. Hyperlinks are found in nearly all Web pages, allowing users to click their way from page to page. Text hyperlinks are often blue and underlined, but don't have to be. When you move the cursor over a hyperlink, whether it is text or an image, the arrow should change to a small hand pointing at the link. When you click it, a new page or place in the current page will open.

Hyperlinks, often referred to as just "links," are common in Web pages, but can be found in other hypertext documents. These include certain encyclopedias, glossaries, dictionaries, and other references that use hyperlinks. The links act the same way as they do on the Web, allowing the user to jump from page to page. Basically, hyperlinks allow people to browse information at hyperspeed.



Hypermedia

Most Web navigation is done by clicking text-based links that open new pages in a Web browser. These links, which are often blue and underlined, are referred to as hypertext, since they allow the user to jump from page to page. Hypermedia is an extension of hypertext that allows images, movies, and Flash animations to be linked to other content.

The most common type of hypermedia is an image link. Photos or graphics on the Web are often linked to other pages. For example, clicking a small "thumbnail" image may open a larger version of the picture in a new window. Clicking a promotional graphic may direct you to an advertiser's website. Flash animations and videos can also be turned into hyperlinks by embedding one or more links that appear during playback.

You can tell if an image or video is a hyperlink by moving the cursor over it. If the cursor changes into a small hand, that means the image or video is linked to another page. Clicking the text, image, or video will open up a new location in your Web browser. Therefore, you should only click a hypertext or hypermedia link when you are ready to leave the current page. If you want to open the link in a new window, you can usually right click the link and select "Open Link in New Window".



Hypertext

Hypertext is text that links to other information. By clicking on a link in a hypertext document, a user can quickly jump to different content. Though hypertext is usually associated with Web pages, the technology has been around since the 1960s. Software programs that include dictionaries and encyclopedias have long used hypertext in their definitions so that readers can quickly find out more about specific words or topics. Apple Computer's HyperCard program also used hypertext, which allowed users to create multi-linked databases. Today, the Web is where hypertext reigns, where nearly every page includes links to other pages and both text and images can be used as links to more content.








Terms
Hacker
Hard Copy
Hard Disk
Hard Token
Hardware
HDMI
HDTV
HDV
Hertz
Heuristic
Hexadecimal
Hibernate
Hit
Home Page
Host
Hover
HTML
HTTP
HTTPS
Hub
Hyper-Threading
Hyperlink
Hypermedia
Hyper Text



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