Segment descriptor

In memory addressing for Intel x86 computer architectures, segment descriptors are a part of the segmentation unit, used for translating a logical address to a linear address. Segment descriptors describe the memory segment referred to in the logical address.
The segment descriptor (8 bytes long in 80286 and later) contains the following fields:
Structure.
The x86 and x86-64 segment descriptor has the following form:
Where the fields stand for: