- In DOS memory management, extended memory refers to memory above the first megabyte (2^20 bytes) of address space in an IBM PC or compatible with an 80286 or later processor. The term is mainly used under the DOS and Windows operating systems. DOS programs, running in real mode or virtual x86 mode, cannot directly access this memory, but are able to do so through an application programming interface called the Extended Memory Specification (XMS). This API is implemented by a driver (such as HIMEM.SYS) or the operating system, which takes care of memory management and copying memory between conventional and extended memory, by temporarily switching the processor into protected mode. In this context, the term “extended memory” may refer to either the whole of the extended memory or only the portion available through this API.
- Star Tales - Norma (ianridpath.com)
Norma is one of the constellations introduced by the French astronomer Nicolas Louis de Lacaille following his mapping of the southern skies in 1751–52. It consists of faint stars between Ara and Lupus that were not catalogued by Ptolemy. On his 1756 planisphere Lacaille called it l’Equerre et la Regle, although in his accompanying star catalogue the name was given simply as l’Équerre. In the notes to his catalogue he described it as representing an architect’s set-square and ruler.
