Memory above the first megabyte of address space in an IBM PC with an 80286 or later processor.
Extended memory is not directly available in real mode, only through EMS, UMB, XMS, or HMA; only applications executing in protected mode can use extended memory directly. In this case, the extended memory is provided by a supervising protected-mode operating system such as Microsoft Windows. The processor makes this memory available through a system of global descriptor tables and local descriptor tables. The memory is “protected” in the sense that memory assigned a local descriptor cannot be accessed by another program without causing a hardware trap. This prevents programs running in protected mode from interfering with each other’s memory.
A protected-mode operating system such as Windows can also run real-mode programs and provide expanded memory to them. DOS Protected Mode Interface is Microsoft’s prescribed method for an MS-DOS program to access extended memory under a multitasking environment.
Having extended memory does not necessarily mean that you have more than one megabyte of memory since the reserved memory area may be partially empty. In fact, if your 386 or higher uses extended memory as expanded memory then that part is not in excess of 1Mb.
See also conventional memory.
- External intercostal muscle
external intercostal muscle n. Any of the muscles with their origin from the lower border of a rib, with insertion into the upper border of the rib below, with nerve supply from the intercostal nerve, and that contract during inspiration and maintain tension in the intercostal spaces to resist mediolateral movement.
[ik-stur-nl-iz-uh m] /ɪkˈstɜr nlˌɪz əm/ noun 1. attention to , especially excessive attention to , as in religion. /ɪkˈstɜːnəˌlɪzəm/ noun 1. exaggerated emphasis on outward form, esp in religious worship 2. a philosophical doctrine holding that only objects that can be perceived by the senses are real; phenomenalism
[ik-stur-nl-uh-zey-shuh n] /ɪkˌstɜr nl əˈzeɪ ʃən/ noun 1. the act or process of . 2. the quality or state of being . 3. something that is .
[ik-stur-nl-ahy-zer] /ɪkˈstɜr nlˌaɪ zər/ noun, Psychology. 1. a person who draws a locus of control from the external world, depending on others as a source of values, ideas, and security.