The size of address bus of 8086 is 20 and is able to address 1 Mbytes ( 
) of physical memory.
The compete 1 Mbytes memory can be divided into 16 segments, each of 64 Kbytes size.
The addresses of the segment may be assigned as 00000H to F0000H respectively.
The offset values are from 00000H to FFFFH so that the physical address range from 00000H to FFFFFH.
If the segmentation is done as per above mentioned way, the segments are called non-overlapping segments.
In some cases segment may overlap also. Suppose a segment starts at a particular address and its maximum size can go up to 64 Kbytes. But if another segment starts before this 64 Kbytes location of the first segment, the two segments are said to be overlapping segment.
The area of memory from the start of the second segment to the possible end of the first segment is called as overlapped segment.
Non-overlapping segments and overlapping segments are shown in the Figure 11.7.