buffer (redirected from buffer zone)

buffer, solution that can keep its relative acidity or alkalinity constant, i.e., keep its pH constant, despite the addition of strong acids or strong bases. Buffer solutions are frequently solutions that contain either a weak acid and one of its salts or a weak base and one of its salts. Many acid-base reactions take place in living organisms. However, for organisms to perform certain vital functions, the body fluids associated with these functions must maintain a constant pH. For example, blood must maintain a pH of close to 7.4 in order to carry oxygen from the lungs to cells; blood is therefore a powerful buffer.

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buffer

Solution usually containing a weak acid and its conjugate weak base, or a salt, of such a composition that the pH is held constant within a certain range. An example is a solution containing acetic acid (CH₃COOH) and the acetate ion (CH₃COO⁻). The pH depends on their relative concentration and can be found with a simple formula involving their ratio. Relatively small additions of acid or base will change the concentration of the two species, but their ratio, and hence the pH, will not change much. Different buffers are useful in different pH ranges; they include phosphoric acid, citric acid, and boric acid, each with their salts. Biological fluids such as blood, tears, and semen have natural buffers to maintain them at the pH required for their proper function. See also law of mass action.

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A reserved segment of memory used to hold data while it is being processed. In a program, buffers are created to hold some amount of data from each of the files that will be read or written. In a streaming media application, the program uses buffers to store an advance supply of audio or video data to compensate for momentary delays.

With regular computer applications, buffers are allocated and deallocated from the general memory pool. In printers and other hardware devices, buffers can be small memory banks used for just one temporary storage function. See buffering, double buffering, buffer overflow, buffer flush and bucket.

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1.		buffer - An area of memory used for storing messages. Typically, a buffer will have other attributes such as an input pointer (where new data will be written into the buffer), and output pointer (where the next item will be read from) and/or a count of the space used or free. Buffers are used to decouple processes so that the reader and writer may operate at different speeds or on different sized blocks of data. There are many different algorithms for using buffers, e.g. first-in first-out (FIFO or shelf), last-in first-out (LIFO or stack), double buffering (allowing one buffer to be read while the other is being written), cyclic buffer (reading or writing past the end wraps around to the beginning).
2.		buffer - An electronic device to provide compatibility between two signals, e.g. changing voltage levels or current capability.