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) contains the following fields:
- A segment base address
- The segment limit which specifies the segment limit
- Access rights byte containing the protection mechanism information
- Control bits