Computer Terms Beginning with "C"

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Source : PC.net

C/C++

C is a high-level programming language that was developed in the mid-1970s. It was originally used for writing Unix programs, but is now used to write applications for nearly every available platform. Compared to most previous languages, C is easier to read, more flexible (can be used for a wide variety of purposes), and more efficient at using memory.

C++, pronounced "C plus plus," is a programming language that was built off the C language. The syntax of C++ is nearly identical to C, but it has object-oriented features, which allow the programmer to create objects within the code. This makes programming easier, more efficient, and some would even say, more fun. Because of the power and flexibility of the language, most software programs today are written in C++.

[MysteRy]

Cable Modem

A cable modem is used for connecting to the Internet and is much faster than a typical dial-up modem. While a 56K modem can receive data at about 53 Kbps, cable modems support data transfer rates of up to 30 Mbps. That's over 500 times faster. However, most ISPs limit their subscribers' transfer rates to less than 6 Mbps to conserve bandwidth.

Another important way that a cable modem is different than a dial-up modem is that it doesn't connect to a phone line. Instead, the cable modem connects to a local cable TV line, hence the term "cable modem." This allows cable modems to have a continuous connection to the Internet. Therefore, there is no need to dial your ISP every time you want to check your e-mail.

Cable modems, which have a much more complex design than dial-up modems, are usually external devices, but some models can be integrated within a computer. Instead of connecting to a serial port like a external dial-up modem, cable modems attach to a standard Ethernet port so they can transfer data at the fastest speed possible.

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Cache

This term is pronounced like "cash" -- not "catch," and definitely not "cashé." There are many different types of caches but they all serve the same purpose. A cache stores recently-used information in a place where it can be accessed extremely fast. For example, a Web browser like Internet Explorer uses a cache to store the pages, images, and URLs of recently visited Web sites on your hard drive. With this neat strategy, when you visit a page you have recently been to, the pages and images don't have to be downloaded to your computer all over again. Because accessing your computer's hard disk is much faster than accessing the Internet, caching Web sites can speed up Web browsing significantly. Most Web browsers allow you to adjust the size of the cache in browser preferences.

Another common type of cache is a disk cache. This stores information you have recently read from your hard disk in the computer's RAM, or memory. Since accessing RAM is much faster than reading data off the hard disk, this can help you access common files and folders on your hard drive much faster.

Another type of cache is a processor cache which stores small amounts of information right next to the processor. This helps make the processing of common instructions much more efficient, thereby speeding up computation time.

[MysteRy]

CAD

Stands for "Computer-Aided Design." Also known by engineers and architects as the best invention of all time. Today, CAD software is used for nearly all three-dimensional designing. Designers can turn an object into an electronic representation more quickly and accurately than by diagraming it with a pencil and paper. Better yet, objects created with CAD software can be moved, resized, and rotated instantly. With a pencil and paper, you can only erase so much before it starts to smudge.

[MysteRy]

Camera RAW

Most digital cameras process and compress the pictures you take immediately after capturing the image. This can be helpful, as it keeps the file sizes low (using JPEG compression) and takes care of color correction, including white-balance, tint, and exposure, so you don't have to. However, some people, such as professional photographers, prefer to have more control over how each image is processed. Therefore, many high-end cameras have the ability to shoot in RAW mode. This mode does not compress the images at all and leaves them completely unprocessed.

Because Camera RAW files are uncompressed, they take up more space than typical JPEG images. In fact, RAW files often require 2 to 3 times more space for each image captured. So, you'll want to have an extra-large memory card in your camera if you plan on shooting in RAW mode. But since RAW photos are not compressed, you maintain the full quality of each image. This can make a noticeable difference when printing images, especially for large prints.

Camera RAW files are also unprocessed, meaning all the photo processing is done on the computer. It is like taking a film negative to a dark room to be developed. The RAW file is the negative and the computer serves as the dark room. With a RAW file, you have complete control over the temperature adjustments (for white-balance), tint, hue, and exposure. However, since Camera RAW files are not typical images, most image-viewing programs will not open them. Therefore, most camera companies include Camera RAW editing software with their high-end cameras. These programs allow you to open RAW files, do the necessary processing, and save them in common image formats such as bitmap, TIFF, and JPEG.

While shooting in Camera RAW mode offers a lot of control over your photos, it takes additional software and extra time to open and edit each picture you take. For most casual photography, using the camera's built-in processing is the most suitable option.

[MysteRy]

Caps Lock

Caps lock is a feature nearly all keyboards have that, when active, capitalizes each letter typed on the keyboard. Unlike most keys on the keyboard, the caps lock key is a "toggle key," which is always in either an on or off position. When off, the letters typed are input like usual. When on, each letter typed is transmitted as an upper-case character. Caps lock does not alter the input from the rest of the keys, such as numbers and symbols.

Because caps lock changes the input of the letters on the keyboard, it is important to know whether it is on or off. Therefore, most keyboards have a light on the caps lock key that turns on when active, indicating caps lock is on. Because passwords are often case-sensitive, it is smart to make sure caps lock is not active when entering login information. Also, it is best not to use caps lock when typing e-mails because IT MAKES IT SEEM LIKE YOU ARE YELLING when you type in all caps.

[MysteRy]

Captcha

Example: "Online forms may include captchas to prevent automated programs from submitting data."

A captcha is a challenge-response test that determines whether a user is human or an automated bot. A typical captcha includes an image of distorted text and a form field for the user to enter the text. Captchas are commonly found at the end of website forms, and must be filled out in order for the form to be submitted. By requiring users to decipher and enter the captcha text, webmasters can prevent automated programs from sending spam or other unwanted data through online forms.

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Card Reader

"Card reader" is the generic term for an input device that reads flash memory cards. It can be a standalone device that connects to a computer via USB or it may be integrated into a computer, printer, or multifunction device. In fact, most multifunction printer/scanner/copiers now have built-in card readers.

Most card readers accept multiple memory card formats, including compact flash (CF), secure digital (SD), and Sony's Memory Stick. Some card readers accept various other formats such as XD, SmartMedia, Microdrive, and Memory Stick Pro Duo cards.

The purpose of a card reader is, not surprisingly, to read the data from a memory card. When you place a memory card into a card reader, it will often show up on your computer as a mounted disk. You can then view the contents of the memory card by double-clicking the card's icon. This icon typically appears on the desktop of Macintosh computers or inside "My Computer" on Windows machines.

Since memory cards most often contain pictures from digital cameras, a photo organization program may automatically open when you insert a memory card into you card reader. This provides an easy way of importing your pictures into your photo album. If you don't want to import photos using the program, you can simply close the program and the card will still be mounted on your computer.

Once you decide to remove the card, make sure you unmount or "eject" the disk before physically removing the card. This will help prevent the data on the card from becoming corrupted.

[MysteRy]

Cc

Stands for "Carbon Copy." The term comes from carbon copying, in which a piece of carbon paper copies writing from one paper to another (often used when filling out forms). However, the term is now commonly used in reference to e-mail. When you send an e-mail message, you typically type the recipient's address in the "To:" field. If you want to send the message to one or more other recipients, you can use the "Cc:" field to add additional addresses. This will send the e-mail to the address in the "To:" field and to each address listed in the "Cc:" field as well.

The "Cc:" option is often used in business communications when a message is intended for one person, but is relevant to other people as well. For example, a retail employee may e-mail another employee saying he can work for her on a certain day. He might include his manager's and assistant manager's e-mail addresses in the "Cc:" field to let them know he is taking the work shift. Similarly, a team member working on a product design may e-mail his boss with the latest design revisions and may "Cc:" the other members of his team to let them know the e-mail has been sent.

"CCing" (yes, it can also be used as a verb) is a quick way to let other people in on your e-mail communications. It is efficient because you don't have to send separate messages to each individual address. However, remember that When you Cc an e-mail, all the recipients can see the other addresses the message was sent to. If you want to hide the additional addresses, use Blind Carbon Copy (Bcc) instead.

[MysteRy]

CCD

Stands for "Charged Coupled Device." CCDs are sensors used in digital cameras and video cameras to record still and moving images. The CCD captures light and converts it to digital data that is recorded by the camera. For this reason, a CCD is often considered the digital version of film.

The quality of an image captured by a CCD depends on the resolution of the sensor. In digital cameras, the resolution is measured in Megapixels (or thousands of or pixels. Therefore, an 8MP digital camera can capture twice as much information as a 4MP camera. The result is a larger photo with more detail.

CCDs in video cameras are usually measured by physical size. For example, most consumer digital cameras use a CCD around 1/6 or 1/5 of an inch in size. More expensive cameras may have CCDs 1/3 of an inch in size or larger. The larger the sensor, the more light it can capture, meaning it will produce better video in low light settings. Professional digital video cameras often have three sensors, referred to as "3CCD," which use separate CCDs for capturing red, green, and blue hues.

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CD

Stands for "Compact Disc." CDs are circular discs that are 4.75 in (12 cm) in diameter. The CD standard was proposed by Sony and Philips in 1980 and the technology was introduced to the U.S. market in 1983. CDs can hold up to 700 MB of data or 80 minutes of audio. The data on a CD is stored as small notches on the disc and is read by a laser from an optical drive. The drives translate the notches (which represent 1's and 0's) into usable data.

The first CDs were audio CDs, which eventually replaced audio tapes (which earlier replaced records). Audio CDs have the advantage of allowing the user to jump to different places on the disc. CDs can also be listened to an unlimited number of times without losing quality. Audio tapes can start to lose quality after listening to them as few as ten times. This is because the laser that reads the data on a CD doesn't put pressure on the disc, whereas the playheads on a tape deck slowly wear away the magnetic strip on the tape.

In 1985, CD-ROMs hit the computer market. Because they could store far more information than floppy discs (700 MB compared to 1.4 MB), CDs soon became the most common software format. In 1988, the CD-R (CD-Recordable) technology was introduced, allowing computer users to burn their own CDs. However, this technology did not become mainstream until the late 1990s. A smaller 3" CD, called "CD-3" is also available and is readable by most tray-loading CD-ROM drives.

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CD-R

Stands for "Compact Disc Recordable." CD-R discs are blank CDs that can record data written by a CD burner. The word "recordable" is used because CD-Rs are often used to record audio, which can be played back by most CD players. However, many other kinds of data can also be written to a CD-R, so the discs are also referred to as "writable CDs."

The data burned onto a CD-R disc is permanent, meaning it can not be altered or erased like the data on a hard drive. Typically, once a CD has been burned, it will not be able to record any more data. Some CD burning programs can record data as "sessions," allowing a disc to be written to mulitple times until it is full. Each session creates a new partition on the disc, meaning a computer will read a disc with multiple sessions as multiple discs. CD-RWs, on the other hand, can be erased and completely re-recorded. Like CDs, the data on CD-RWs cannot be altered, meaning the disc has to be completely erased each time you want to add new data.

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CD-ROM

Stands for "Compact Disc Read-Only Memory." A CD-ROM is a CD that can be read by a computer with an optical drive. The "ROM" part of the term means the data on the disc is "read-only," or cannot be altered or erased. Because of this feature and their large capacity, CD-ROMs are a great media format for retail software. The first CD-ROMs could hold about 600 MB of data, but now they can hold up to 700 MB. CD-ROMs share the same technology as audio CDs, but they are formatted differently, allowing them to store many types of data.

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CD-RW

Stands for "Compact Disc Re-Writable." A CD-RW is a blank CD that can be written to by a CD burner. Unlike a CD-R (CD-Recordable), a CD-RW can be written to multiple times. The data burned on a CD-RW cannot be changed, but it can be erased. Therefore, you have to completely erase a CD-RW every time you want to change the files or add new data. While it may be somewhat inconvenient, this capability makes CD-RWs a good choice for making frequent backups. However, because CD-RWs can be erased, they don't store data reliably for as long as CD-Rs do. Therefore, you should use regular CD-Rs for long-term backups.

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CDMA

Stands for "Code Division Multiple Access." CDMA is a wireless transmission technology that was developed during World War II by the English allies to avoid having their transmissions jammed. After the war ended, Qualcomm patented the technology and made it commercially available as a digital cellular technology. Now CDMA is a popular communications method used by many cell phone companies.

Unlike the GSM and TDMA technologies, CDMA transmits over the entire frequency range available. It does not assign a specific frequency to each user on the communications network. This method, called multiplexing, is what made the transmissions difficult to jam during World War II. Because CDMA does not limit each user's frequency range, there is more bandwidth available. This allows more users to communicate on the same network at one time than if each user was allotted a specific frequency range.

Because CDMA is a digital technology, analog audio signals must be digitized before being transmitted on the network. CDMA is used by 2G and 3G wireless communications and typically operates in the frequency range of 800 MHz to 1.9 GHz.