Use all RAM memory in MS-DOS

How can I access more than Conventional and开发者_StackOverflow社区 Extended memory?

The XMS version 3.0 specification allows access to up to 4GB. See the Wikipedia article.

MS-DOS is a 16-bit operating system, which limits its inherent ability to address large amounts of memory. I believe the limit for addressable memory is 16 megabytes in protected mode, using extended memory (80286 processors and above).

See here: http://en.wikipedia.org/wiki/RAM_Limit

Nowadays, small application spaces, such as embedded controllers, typically use one of the many variants of Linux that are widely available.