Accelerated Graphics Port (AGP)
An interface specification developed by Intel Corporation. AGP is based on PCI, but is designed especially for the throughput demands of 3-D graphics. Rather than using the PCI bus for graphics data, AGP introduces a dedicated point-to-point channel so that the graphics controller can directly access main memory. The AGP channel is 32 bits wide and runs at 66 MHz. This translates into a total bandwidth of 266 MBps, as opposed to the PCI bandwidth of 133 MBps. AGP also supports two optional faster modes, with throughputs of 533 MBps and 1.07 GBps. In addition, AGP allows 3-D textures to be stored in main memory rather than video memory. You can differentiate a AGP card/slot from a PCI (see definition below), by looking at two things:
- The contacts on the card will be much closer together, and also appear in a staggered formation (see photo).
- The contacts will be flushed back a greater distance from the faceplate than found in PCI cards.
Digital Video Interface (DVI)
DVI is a specification created by the Digital Display Working Group (DDWG) to accommodate analog and digital monitors with a single connector. There are three different DVI configurations: DVI-A, designed for analog signals, DVI-D, designed for digital signals, and DVI-I (integrated), designed for both analog and digital signals.
IEEE 1394 (Firewire)
A very fast external bus standard that supports data transfer rates of up to 400Mbps (in 1394a) and 800Mbps (in 1394b). Products supporting the 1394 standard go under different names, depending on the company. Apple, which originally developed the technology, uses the trademarked name FireWire.
In a computer, a jumper is a pair of prongs that are electrical contact points set into the computer motherboard or an adapter card. When you set a jumper, you place a plug on the prongs that completes a contact. Jumper settings tell the computer how it is configured and what operations can be performed. Computers come with jumpers preset. Instructions are sometimes provided so that the owner can reset the jumpers when new equipment is added. The latest trend, however, is Plug and Play equipment that does not require manual setting of jumpers. A group of jumpers is sometimes called a jumper block.
LPT (Parallel) Port
LPT (line print terminal) is the usual designation for a parallel port connection to a printer or other device on a personal computer. Most PCs come with one or two LPT connections designated as LPT1 and LPT2. Some systems support a third, LPT3. Whatever the number, LPT1 is the usual default. You can add a parallel port for a second printer or other device by buying and adding a parallel port adapter card to your computer. An LPT port can be used for an input device such as QuickCam, a video camera used with CU-SeeMe.