Glossary » R

Redundant Array of Inexpensive Disks. RAID comes in several different configurations depending on what kind of hardware you have. IDE or S-ATA RAIDs tends to come in the following configurations. RAID-0 – This is also referred to as “striping” as you take two identical hard drives and turn them in to one large volume. This gives some added performance, but if one hard drive fails you loose all the data on both. RAID-1 – This is a semi expensive solution as you need two identical drives where the second drive keeps an copy of the first. This is very good for data security but doesn’t add any performance. RAID-0+1 or RAID-10 – This is a combination of the two above, but requires four identical hard drives, making this a very expensive solution. The advantage is that you gain both performance and data security as all the drives are “striped”, but in two separate “arrays”. The second “array” keeps an identical copy of the first “array”. There are several other types of RAID, but they are usually reserved for servers or high-end workstations.

Random Access Memory. This is memory that can be read from or written to on demand.

Random Access Memory Digital-To-Analogue Converter. This can be a part of the GPU or a discrete chip but in both cases its job is to convert the digital information held in graphics memory to an analogue signal that can be sent to your monitor or TV. The quality of the RAMDAC can affect image quality and its speed dictates which vertical refresh rates are available at high resolutions.

The matrix of invisible lines on which the image is drawn on a CRT. The raster is made up of horizontal lines that are written sequentially from the top of the CRT to the bottom.

Image format offered on high-end cameras which stores the raw data from the imaging chip before it’s been processed; this file is usually stored uncompressed or with lossless compression. RAW images are normally less than half the size of TIFFs, while offering the greatest potential image quality, but must be processed into a usable image format using software later.

Option which fires the flash at the end of a long exposure, thereby freezing the subject with any motion trailed behind it instead of in-front. Ideal for trailing sparklers and headlights.

The number of times a monitor refreshes or ‘redraws’ the image displayed on the screen, per second. Expressed in Hz, the minimum accepted refresh rate needed to avoid noticeable flicker is around 72Hz. LCDs do not suffer from this phenomenon.

The process of calculation involved in producing effects or compressed video that can then be viewed in real time.

The conversion of raw mathematical data into a final recognisable image.

The number and density of pixels available on a display in order to create an image. Usually expressed in horizontal x vertical values. For example a 21in CRT monitor typically has a recommended resolution of 1,600 pixels arranged horizontally and 1,200 arranged vertically, giving rise to a total of 1,920,000 available pixels. Resolution also refers to the sharpness of a monitor’s picture. This term can also describe the number and density of pixels that can be captured using the sensors in both digital cameras and scanners.

The amount of time needed for an LCD pixel to reach its ‘on’ (rise) state and then back to ‘off’ (fall) again. The lower the response time the better the monitor will display fast moving graphics. See persistence, active matrix and passive matrix

Red, green and blue.

Animation technique where live footage is used as a reference.