Memory Map; Conventional Memory - Toshiba T2150CD Series Manual

Using RAM
Manufacturers of personal computers have adopted the following names to describe the
functions of various parts of RAM:

Conventional memory

Upper memory
High memory
Extended memory
Expanded memory
The following memory map shows how RAM is allocated.

Memory Map

This diagram illustrates how your computer allocates memory. Although memory size is
referred to in thousands of bytes (characters), or in kilobytes, the actual quantities are slightly
larger. This is because a kilobyte is actually 1,024 bytes (2
measurements are usually rounded off to simplify discussion.
Conventional Memory
MS-DOS can directly access only 1 megabyte (1024 kilobytes) of memory at a time. This is
the area between 0KB and 1MB on the memory map. The first 640 kilobytes in this area is
called conventional memory.
Conventional memory is used as a work area by MS-DOS and most application software.
Extended BIOS Data Area
This is 1KB of RAM loaded at 639KB. It is used to support extended BIOS functions
including support for PS/2 pointing devices.
), not 1,000 bytes. Memory
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