What Does Reserved Memory Mean?
Reserved memory describes storage space that's set aside by a technology for its use. The idea is that memory reserved for a specific process cannot be used by other processes.
While conventional computers had a specific amount of reserved memory for their core processes and other amounts of memory reserved for programs, in more sophisticated network virtualization systems, virtual machines may have different kinds of memory reservations, some of which may be changed by programmers or IT administrators. Because network fertilization involves setting up virtual data storage spaces that are not actual physical machines or workstations, the idea of memory reservation can apply differently to these newer and more advanced systems
Techopedia Explains Reserved Memory
One of the most common examples of reserved memory is in conventional MS-DOS PCs, where there is a standard reserved memory space between 640 KB and 1 MB that is allocated for various items like the basic input/output system (BIOS) that controls basic operating system functions, as well as video cards and some kinds of device drivers. In some cases, professionals use the term reserved memory interchangeably with the upper memory block, or state that an upper memory block may "use" a reserved memory space. Areas of a UMB may also be allocated for specific utilities. Some individuals may also use reserved memory interchangeably with allocated memory, which is random access memory reserved for software applications.
Other detailed explanations of reserved memory involve contrasting this term to the term "committed memory," which describes memory that has been fully prepared for use by a certain program. Developers point out that committing memory may involve additional steps after it has already been reserved or allocated for a particular program. In general, memory that has been reserved but not committed is lying unused in a system.