Stands for “Simple Mail Transfer Protocol.” This is the protocol used for sending e-mail over the Internet. Your e-mail client (such as Outlook, Eudora, or Mac OS X Mail) uses SMTP to send a message to the mail server, and the mail server uses SMTP to relay that message to the correct receiving mail server. Basically, SMTP is a set of commands that authenticate and direct the transfer of electronic mail. When configuring the settings for your e-mail program, you usually need to set the SMTP server to your local Internet Service Provider’s SMTP settings (i.e. “smtp.yourisp.com”). However, the incoming mail server (IMAP or POP3) should be set to your mail account’s server (i.e. hotmail.com), which may be different than the SMTP server.
The term “pixel” is actually short for “Picture Element.” These small little dots are what make up the images on computer displays, whether they are flat-screen (LCD) or tube (CRT) monitors. The screen is divided up into a matrix of thousands or even millions of pixels. Typically, you cannot see the individual pixels, because they are so small. This is a good thing, because most people prefer to look at smooth, clear images rather than blocky, “pixelated” ones. However, if you set your monitor to a low resolution, such as 640×480 and look closely at your screen, you will may be able to see the individual pixels. As you may have guessed, a resolution of 640×480 is comprised of a matrix of 640 by 480 pixels, or 307,200 in all. That’s a lot of little dots.
Each pixel can only be one color at a time. However, since they are so small, pixels often blend together to form various shades and blends of colors. The number of colors each pixel can be is determined by the number of bits used to represent it. For example, 8-bit color allows for 2 to the 8th, or 256 colors to be displayed. At this color depth, you may be able to see “graininess,” or spotted colors when one color blends to another. However, at 16, 24, and 32-bit color depths, the color blending is smooth and, unless you have some kind of extra-sensory vision capability, you should not see any graininess.
An autoresponder is a program or script on a mail server that automatically replies to e-mails. Though it is run from the mail server, an autoresponder can usually be set up by the user through a Web-based interface. For example, a company might set up an autoresponder for their support e-mail address to let users know they have received their support requests. The automated reply might read something like, “Thank you, we have received your message. One of our technicians will attempt to answer your question after he finishes his dart game in the lobby.”
Individuals may also use autoresponders to let people know when they are away from their computer and won’t be able to respond to any e-mails for awhile. For example, you might set up an autoresponder for your personal e-mail address to say, “Sorry, I am on vacation in the Bahamas indefinitely. I’ll respond to your message whenever I decide to come back.” Of course, it is important to reply to messages even after the autroresponder has sent a esponse. After all, most people like to communicate with other people rather than computers.
FireWire is an I/O interface developed by Apple Computer. It is also known as IEEE 1394, which is the technical name standardized by the IEEE. Other names for IEEE 1394 include Sony i.Link and Yamaha mLAN, but Apple’s FireWire name the most commonly used.
There are two primary versions of the FireWire interface – FireWire 400 (IEEE 1394a) and FireWire 800 (IEEE 1394b). FireWire 400 uses a 6-pin connector and supports data transfer rates of up to 400 Mbps. FireWire 800 uses a 9-pin connector and can transfer data at up to 800 Mbps. The FireWire 800 interface, which was introduced on Macintosh computers in 2003, is backwards compatible with FireWire 400 devices using an adapter. Both interfaces support daisy chaining and can provide up to 30 volts of power to connected devices.
FireWire is considered a high-speed interface, and therefore can be used for connecting peripheral devices that require fast data transfer speeds. Examples include external hard drives, video cameras, and audio interfaces. On Macintosh computers, FireWire can be used to boot a computer in target disk mode, which allows the hard drive to show up as an external drive on another computer. Mac OS X also supports networking two computers via a FireWire cable.
While FireWire has never been as popular as USB, it has remained a popular choice for audio and video professionals. Since FireWire supports speeds up to 800 Mbps, it is faster than USB 2.0, which maxes out at 480 Mbps. In fact, even FireWire 400 provides faster sustained read and write speeds than USB 2.0, which is important for recording audio and video in real-time. Future versions of IEEE 1394, such as FireWire 1600 and 3200, were designed to support even faster data transfer speeds. However, the FireWire interface has been superseded by Thunderbolt, which can transfer data at up to 10,000 Mbps (10 Gbps) and is backwards compatible with multiple interfaces.
Though software plug-ins might not make your room smell as nice as the scented ones you stick in an outlet, they are still useful. A software plug-in is an add-on for a program that adds functionality to it. For example, a Photoshop plug-in (such as Eye Candy) may add extra filters that you can use to manipulate images. A browser plug-in (such as Macromedia Flash or Apple QuickTime) allows you to play certain multimedia files within your Web browser. VST plug-ins add effects for audio recording and sequencing programs such as Cubase and Logic Audio.
Most graphics and audio programs today support plug-ins since they are a convenient way to expand the capabilities of the program. Though some plug-ins may be shipped with the program, most are developed by third-parties and are sold separately. Because companies that make browser plug-ins are often competing for a standard (such as Flash and QuickTime), these plug-ins are usually available as free downloads from the Internet.
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.
Stands for “Redundant Array of Independent Disks.” RAID is a method of storing data on multiple hard disks. When disks are arranged in a RAID configuration, the computer sees them all as one large disk. However, they operate much more efficiently than a single hard drive. Since the data is spread out over multiple disks, the reading and writing operations can take place on multiple disks at once. This can speed up hard drive access time significantly. Multiple hard drives may not improve hard disk performace as much as multiple processors may enhance the CPU performance, but it is based on a similar logic.
The benefits of RAID come from a technique called “striping,” which splits up the stored data among the available drives. The “stripes” of data are usually a couple of megabytes large and are interleaved between the drives. The striping system also increases the mean time between failure (MTBF), when reading data. This allows more data to be read accurately in a short period of time. The benefits of the RAID system are especially noticeable when storing large amounts of data. Therefore, many Web hosting and Internet Service Providers use RAID to store data for their clients.
In computing, a stack is a data structure used to store a collection of objects. Individual items can be added and stored in a stack using a push operation. Objects can be retrieved using a pop operation, which removes an item from the stack.
When an object is added to a stack, it is placed on the top of all previously entered items. When an item is removed, it can either be removed from the top or bottom of the stack. A stack in which items are removed the top is considered a “LIFO” (Last In, First Out) stack. You can picture a LIFO stack as a deck of cards where you lay individual cards on the deck, then draw cards from the top. In a “FIFO” (First In, First Out) stack, items are removed the bottom. You can picture a FIFO stack as a row in a vending machine where items are dispensed in the order they were placed in the machine.
Stacks have several applications in commuter programming. LIFO stacks, for example, can be used to retrieve recently used objects, from a cache. FIFO stacks may be used to ensure data is retrieved in the order it was entered, which may be used for processing data in a queue.
While stacks are commonly used by software programmers, you will typically not notice them while using a program. This is because the creation of stacks and push and pop operations are performed in the background while an application is running and are not visible to the user. However, if a stack runs out of memory, it will cause a “stack overflow.” If not handled correctly by the program, a stack overflow may generate an error message or cause the program to crash.
NOTE: The term “stack” may also refer to a protocol stack, which consists of multiple network protocols that work together. Each protocol is categorized into one of seven different layers defined in the OSI model.
The motherboard is the main circuit board of your computer and is also known as the mainboard or logic board. If you ever open your computer, the biggest piece of silicon you see is the motherboard. Attached to the motherboard, you’ll find the CPU, ROM, memory RAM expansion slots, PCI slots, and USB ports. It also includes controllers for devices like the hard drive, DVD drive, keyboard, and mouse. Basically, the motherboard is what makes everything in your computer work together.
Each motherboard has a collection of chips and controllers known as the chipset. When new motherboards are developed, they often use new chipsets. The good news is that these boards are typically more efficient and faster than their predecessors. The bad news is that older components often do not work with new chipsets. Of course, if you are planning on upgrading multiple components, it may be more cost-effective to just buy a new computer.
Stands for “Personal Information Manager.” A PIM is a software application that serves as a planner, notebook, and address book all in one. It can also include things like a calculator, clock , and photo album. PIMs are especially popular for PDAs (Personal Digital Assistants), since this is why most people have them. However, for those of us who don’t have all the latest portable gadgets, PIM programs are also developed for desktop computers.