Month: August 2016

Tech Terms: CPA

Stands for “Cost Per Action,” and is used in online advertising. CPA defines how much revenue a publisher receives when a user clicks an advertisement on his website and then completes a certain action. For example, a publisher may place a banner or text link from an advertiser on his website. When a user clicks the link, she is directed to the advertiser’s website. She might then be asked to fill out a form or take a survey. If she completes the form or survey, the action has been completed, and the advertiser pays the publisher a certain amount based on the CPA.

CPA and CPL (cost per lead) are often used interchangeably, though CPA is more generic.


Tech Terms: Virtual Memory

The term “virtual” is typically overused in the computer world, it is aptly placed in the phrase “virtual reality.” According to the American Heritage Dictionary, virtual means “existing or resulting in essence or effect though not in actual fact, form, or name.” It can also mean “created, simulated, or carried on by means of a computer or computer network.” Therefore, virtual reality is best described as an illusion of reality created by a computer system.

A person may enter a world of virtual reality by putting on special glasses and headphones attached to a computer system running the virtual reality program. These devices immerse the user with the sights and sounds of the virtual world. Some virtual reality systems allow the user to also wear gloves with electronic sensors that can be used to touch or move virtual objects. As the user moves his head or hands, the computer moves the virtual world accordingly in real-time.

Virtual reality has been widely used for entertainment purposes, but the technology has found its way into the military and medical fields as well. While virtual reality systems have advanced significantly over the past decade, for the most part they are still more “virtual” than reality.


Tech Terms: Virtual Memory

Memory is hardware that your computer uses to load the operating system and run programs. It consists of one or more RAM chips that each have several memory modules. The amount of real memory in a computer is limited to the amount of RAM installed. Common memory sizes are 256MB, 512MB, and 1GB.

Because your computer has a finite amount of RAM, it is possible to run out of memory when too many programs are running at one time. This is where virtual memory comes in. Virtual memory increases the available memory your computer has by enlarging the “address space,” or places in memory where data can be stored. It does this by using hard disk space for additional memory allocation. However, since the hard drive is much slower than the RAM, data stored in virtual memory must be mapped back to real memory in order to be used.

The process of mapping data back and forth between the hard drive and the RAM takes longer than accessing it directly from the memory. This means that the more virtual memory is used, the more it will slow your computer down. While virtual memory enables your computer to run more programs than it could otherwise, it is best to have as much physical memory as possible. This allows your computer to run most programs directly from the RAM, avoiding the need to use virtual memory. Having more RAM means your computer works less, making it a faster, happier machine.


Tech Terms: iTunes

iTunes is an audio playback program developed by Apple Computer. You can use iTunes to import songs from CDs as well as other audio files from your hard drive. The program can also download songs (for a small fee) from the iTunes Music Store. While songs are the most common files played by iTunes, you can also play spoken word files, such as audio books or other recordings. iTunes also has a radio option that allows you to play live streams of Internet radio from a variety of stations.

Each file you import with iTunes get stored in the iTunes library. Fortunately, the library can be organized into multiple playlists, which is especially helpful when you have thousands of songs. (Yes, some people have over 10,000 songs in their library.) You can also create “smart playlists,” which store songs according to the parameters you set. For example, if you want a playlist of only rock music, you can create a smart playlist that only holds songs where the “Genre” tag contains “Rock.” iTunes is the software that comes with the iPod, and allows you to transfer your playlists from your computer to your iPod. Like the iPod, iTunes can be used on a Mac or PC.


Tech Terms: iPod

The iPod is a portable music player developed by Apple Computer. Though it is an Apple product, the iPod can be used with both Macs and PCs. The iTunes software, also created by Apple, is used to organize and transfer songs and playlists to the iPod. Both iTunes and the iPod support a wide variety of audio formats, including MP3, AAC, WAV, and AIFF. MP3 is the most common audio compression format, while AAC is the format used by the iTunes Music Store. WAV and AIFF are nearly identical formats that store CD-quality audio.

Since introducing the iPod in 2001, Apple has released several new versions of the popular device. These include iPod, iPod mini, iPod Special Edition, iPod photo, and iPod shuffle. iPod mini is a smaller version of the iPod that comes in various colors and stores fewer songs. iPod Special Edition is a variation of the basic iPod (the first being a black U2 iPod with the signatures of the band members on the back). iPod photo is an iPod with a color screen that allows users to store and view a library of photos as well as play music. iPod shuffle is an extra small iPod that only holds a couple hundred songs and does not have a screen.

All iPods store data on an internal hard drive, except the iPod Shuffle, which uses flash memory. This means each iPod, including the shuffle, can also be used as a hard drive. Aside from being a music player, the iPod can serve as a backup device, a basic organizer, and an alarm clock. To transfer files to the iPod, you must first connect it to your computer using a USB or Firewire cable. iTunes can automatically transfer your playlists and songs or you can change the program’s preferences to manually update the iPod.

Because of its superb interface and unmatched ease of use, the iPod has become the staple product of the portable music player market. Granted, the “cool factor” of owning an iPod has certainly helped it gain popularity as well.


Tech Terms: Debugging

Even experienced software programmers usually don’t get it right on their first try. Certain errors, often called bugs, can occur in programs, causing them to not function as the programmer expected. Sometimes these errors are easy to fix, while some bugs are very difficult to trace. This is especially true for large programs that consist of several thousand lines of code.

Fortunately, there are programs called debuggers that help software developers find and eliminate bugs while they are writing programs. A debugger tells the programmer what types of errors it finds and often marks the exact lines of code where the bugs are found. Debuggers also allow programmers to run a program step by step so that they can determine exactly when and why a program crashes. Advanced debuggers provide detailed information about threads and memory being used by the program during each step of execution. You could say a powerful debugger program is like OFF! with 100% deet.


Tech Terms: Debug

Computer programmers, like everybody else, are not perfect. This means the programs they write sometimes have small errors, called “bugs,” in them. These bugs can be minor, such as not recognizing user input, or more serious, such as a memory leak that crashes the program. Before releasing their software to the public, programmers “debug” their programs, eliminating as many errors as possible. This debugging process often takes a long time, as fixing some errors may introduce others. Debugging your windshield at a gas station is much easier than debugging a computer program.


Tech Terms: VPI

Stands for “Virtual Path Identifier.” The VPI is an 8-bit header inside each ATM cell that indicates where the cell should be routed. ATM, or asynchronous transfer mode, is a method of sending data in small packets of fixed sizes. It is used by many ISPs (Internet Service Providers) for transferring data to client computers.

As an ATM cell moves across a network, it typically passes through several ATM switches. The VPI tells the switches where to route the packet of information, or what path to take. Hence the name, “virtual path identifier.” The VPI is used in conjunction with the VCI, or virtual channel identifier.


Tech Terms: VCI

Stands for “Virtual Channel Identifier.” The VCI, used in conjunction with the VPI (virtual path indicator), indicates where an ATM cell is to travel over a network. ATM, or asynchronous transfer mode, is a method that many ISPs (Internet Service Providers) use to transfer data to client computers. Because ATM sends packets over fixed channels, the data is easier to track than information sent over the standard TCP/IP protocol.

The VCI within each ATM cell defines the fixed channel on which the packet of information should be sent. It is a 16-bit field, compared to the VPI, which is only 8 bits. Since this numerical tag specifies the virtual channel that each packet belongs to, it prevents interference with other data being sent across the network.


Tech Terms: Leaf

What does a computer’s hard disk have in common with a tall oak? While it may not look like a tree on the outside, the hard disk is organized the same way. Directories of files and folders on a hard drive are organized into branches, where each directory is a branch with files and folders. Folders make up the branches, while files are the leaves. Therefore a leaf is a file within a directory on your hard drive.

Technically speaking, a leaf is a node on a tree with no child nodes. Because files cannot have child nodes like folders can, they are always leafs. When referring to a tree structure, a leaf can also be called a leaf node.