Memory Barriers
Memory-mapped I/O is the cause of memory barriers in older generations of computers. The 640 KiB barrier is due to the IBM PC placing the Upper Memory Area in the 640–1024 KiB range (of its 20-bit memory addressing).
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Famous quotes containing the words memory and/or barriers:
“When he became all eye when one was present, and all memory when one was gone; when the youth becomes the watcher of windows, and studious of a glove, a veil, a ribbon, or the wheels of a carriage, when no place is too solitary, and none too silent.”
—Ralph Waldo Emerson (1803–1882)
“The majority of women, they have half-a-glass too much and let down their barriers a little. Then they wake up in the morning, riddled with guilt and think they can reclaim their virtue by saying, “I don’t remember.””
—Blake Edwards (b. 1922)