MEMORY SEGMENTATION

The memory in an 8086/8088 based system is organized as segmented memory. In this scheme, the complete physically available memory may be divided into a number of logical segments. Each segment is 64K bytes in size and is addressed by one of the segment registers. The 16-bit contents of the segment register actually point to the starting location of a particular segment.To address aspecific memory location within a segment, we need an offset address. The offset address is also 16-bit long so that the maximum offset value can be FFFFH, and the maximum size of any segment is thus 64K locations.The CPU 8086 is able to address 1Mbytes of physical memory. The complete 1Mbyte memory can be divided into 16 segments, each of 64Kbytes size. The addresses of the segments (segment base address) may be assigned as 0000H to F000H respectively. The offset address values are from 0000H to FFFFH so that the physical addresses range from 00000H to FFFFFH. In the above case, the segments are called non-overlapping segments. The non-overlapping segments are  in some cases, however, the segments may be overlapping as  Suppose a segment starts at a particular address and its maximum size can be 64Kbytes. But, if another segment starts before this 64Kbytes location of the first segment, the two segments are said to be overlapping segments. The area of memory from the start of the second segment to the possible end of the first segment is called as overlapped segment area.

+++++Love isn't something you find.                  Love is something that finds you.+++++ @ Loretta Young