Later Developments
The x86-64 architecture does not use segmentation in long mode (64-bit mode). Four of the segment registers: CS, SS, DS, and ES are forced to 0, and the limit to 264. The segment registers FS and GS can still have a nonzero base address. This allows operating systems to use these segments for special purposes.
For instance, Microsoft Windows on x86-64 uses the GS segment to point to the Thread Environment Block, a small data structure for each thread, which contains information about exception handling, thread-local variables, and other per-thread state. Similarly, the Linux kernel uses the GS segment to store per-CPU data.
Read more about this topic: X86 Memory Segmentation
Famous quotes containing the word developments:
“The developments in the North were those loosely embraced in the term modernization and included urbanization, industrialization, and mechanization. While those changes went forward apace, the antebellum South changed comparatively little, clinging to its rural, agricultural, labor-intensive economy and its traditional folk culture.”
—C. Vann Woodward (b. 1908)
“I don’t wanna live in a city where the only cultural advantage is that you can make a right turn on a red light.
Freedom from labor itself is not new; it once belonged among the most firmly established privileges of the few. In this instance, it seems as though scientific progress and technical developments had been only taken advantage of to achieve something about which all former ages dreamed but which none had been able to realize.”
—Hannah Arendt (1906–1975)