Tandy 1000 MS-DOS Reference Manual page 256

Chapter 11 I Linking Object Modules
In MS-DOS, memory can be divided into segments, classes, and
groups. The following diagram illustrates these concepts.
Segment Segment Segment
14 15 16
Segment Segment Segment
3 4 5
Memory
Segment
11
Segment
8
Segment
9
Segment
10
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Segment Segment
17 18
Segment Segment Segment Segment
. 19 20 21 22
I
1
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shaded area
=
group (64K bytes addressable)
Example
Segment Class
Name
Name
Segment 1 PROG.1 CODE
Segment 2 PROG.2 CODE
Segment 12
PROG.3
DATA
Note that segments must have different segment names but may
or may not have the same class name. Segments 1, 2, and 12
form a group; the group address is the lowest address of Segment
1 (the lowest address in memory).
Segment
A segment is a contiguous area of memory up to 64K bytes long.
It can be located anywhere in memory on a paragraph (16-byte)
boundary. The contents of a segment are addressed by a segment
address and an offset within that segment. Segments can
overlap.
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