Search results
Results From The WOW.Com Content Network
Virtual memory combines active RAM and inactive memory on DASD [a] to form a large range of contiguous addresses.. In computing, virtual memory, or virtual storage, [b] is a memory management technique that provides an "idealized abstraction of the storage resources that are actually available on a given machine" [3] which "creates the illusion to users of a very large (main) memory".
A page, memory page, or virtual page is a fixed-length contiguous block of virtual memory, described by a single entry in a page table.It is the smallest unit of data for memory management in an operating system that uses virtual memory.
The Intel 8080 used by these computers was an 8-bit processor, with 16-bit address space, which allowed it access up to 64 KB of memory; .COM executables used with CP/M have a maximum size of 64 KB due to this, as do those used by DOS operating systems for 16-bit microprocessors.
The ARM AArch64 Virtual Memory System Architecture allows from 48 to 56 bits for virtual memory and, for any given processor, from 32 to 56 bits for physical memory. [ 32 ] The DEC Alpha specification requires minimum of 43 bits of virtual memory address space (8 TB) to be supported, and hardware need to check and trap if the remaining ...
This means that 48 bits of virtual page number are translated, giving a virtual address space of up to 256 TB. For some processors, a mode can be enabled with a fifth table, the 512-entry page-map level 5 table ; this means that 57 bits of virtual page number are translated, giving a virtual address space of up to 128 PB.
Single-level storage (SLS) or single-level memory is a computer storage term which has had two meanings. The two meanings are related in that in both, pages of memory may be in primary storage or in secondary storage (disk), and that the physical location of a page is unimportant to a process.
This roughly 64-kilobyte region of memory was known as the High Memory Area (HMA), and later versions of DOS could use it to increase the available "conventional" memory (i.e. within the first MB). With the addition of the HMA, the total address space is approximately 1.06 MB.
For example, we can create smaller 1024-entry 4 KB pages that cover 4 MB of virtual memory. This is useful since often the top-most parts and bottom-most parts of virtual memory are used in running a process - the top is often used for text and data segments while the bottom for stack, with free memory in between.