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De - Pt| English Dictionary: IBM 3270 | by the DICT Development Group |
| 1 result for IBM 3270 | |
| From The Free On-line Dictionary of Computing (15Feb98) [foldoc]: | |
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IBM 3270 "Display Devices", normally used to talk to {IBM} {mainframes}. The 3270 attempts to minimise the number of {I/O} {interrupts} required by accepting large blocks of data, known as datastreams, in which both text and control (or formatting functions) are interspersed allowing an entire screen to be "painted" as a single output operation. The concept of "formatting" in these devices allows the screen to be divided into clusters of contiguous character cells for which numerous attributes (color, highlighting, {character set}, protection from modification) can be set. Further, using a technique known as 'Read Modified' the changes from any number of formatted fields that have been modified can be read as a single input without transferring any other data, another technique to enhance the terminal throughput of the CPU. The 3270 had twelve, and later twenty-four, special Programmed Function Keys, or PF keys. When one of these keys was pressed, it would cause the device to generate an I/O {interrupt} and present a special code identifying which key was pressed. {Application program} functions such as termination, page-up, page-down or help could be invoked by a single key-push, thereby reducing the load on very busy processors. A version of the {IBM PC} called the "3270 PC" was released in October 1983. It included 3270 {terminal emulation}. {tn3270} is modified version of {Telnet} which acts as a 3270 {terminal emulator} and can be used to connect to an IBM computer over a network. See also {broken arrow}. (1995-02-07) | |
