On DOS systems, conventional memory refers to the portion of memory that is available to standard DOS programs. DOS systems have an address space of 1MB (megabyte), but the top 384K (called upper memory) is reserved for system use. This leaves 640K of conventional memory. Everything above 1MB is either extended or expanded memory.
Since 1995, more than 100 tech experts and researchers have kept Webopedia’s definitions, articles, and study guides up to date. For more information on current editorial staff, please visit our About page.