Glossary - Index R
Ram: Random Access Memory - When you run an application the program is called up from its permanent storage area (like the hard drive, floppy disk, or CD-ROM) and moved into the RAM, where it sends requests to the CPU. Running out of Ram causes it to be sent to the hard drive, which is slower.
RAMDAC: Random Access Memory to Digital Analog Converter - A chip on videocard which turns digital signals to analog ones which can be outputed to a monitor. The faster the RAMDAC (measured in MHz), the higher the screen refresh rates that the card will support at each given resolution.
RDRAM: Rambus DRAM - A DRAM architecture that has a huge amount of memory bandwidth, however has a high latency penalty. RDRAM is best suited for processors that need high bandwidth like Pentium 4 processors.
Refresh Rate: The amount of times the monitor refreshes (redraws) the picture on the screen. Lower rates, around 60 Hz will appear to flicker, especially under lighting. Refresh rates above 75 Hz are recommended since anything lower will cause headaches after a prolonged period of time.
Resolution: Resolution is a measure of graphics that's used to describe what a printer can print, a scanner can scan, and a monitor can display. In printers and scanners, resolution is measured in dots per inch (dpi)--the number of pixels a device can fit in an inch of space..
Riser: A device that is an add from another card, takes up an expansion slot however doens't plug directly into the motherboard.
RJ-11: This is the standard telephone connector--a tab snaps into the socket and has to be pressed to remove the connector from the wall. An ordinary phone circuit uses two wires. The RJ-11 jack has room for up to four wires, but at a glance it's easy to mistake with the larger RJ-45 jack, which can house up to eight wires.
RJ-45: RJ-45 connectors look a bit like a standard phone connector but are twice as wide (with eight wires). RJ-45s are used for hooking up computers to local area networks (LANs) or for phones with lots of lines.
ROM: ROM is a storage chip that typically contains hardwired instructions for use when a computer starts (boots up). The instructions, contained in a small program called the BIOS (basic input/output system) load from ROM and start up the hard disk so that the operating system (OS) can be loaded.
Router: A device that forwards data packets along networks. A router is connected to at least two networks, commonly two LANs or WANs or a LAN and its ISPís network. Routers are located at gateways, the places where two or more networks connect. Routers use headers and forwarding tables to determine the best path for forwarding the packets, and they use protocols such as ICMP to communicate with each other and configure the best route between any two hosts.