Protected Mode - History

History

The Intel 8086, the predecessor to the 286, was originally designed with a 20-bit address bus for its memory. This allowed the processor to access 220 bytes of memory, equivalent to 1 megabyte. At the time, 1 megabyte was considered a relatively large amount of memory, so the designers of the IBM Personal Computer reserved the first 640 kilobytes for use by applications and the operating system and the remaining 384 kilobytes for the BIOS (Basic Input/Output System) and memory for add-on devices.

As the cost of memory decreased and memory use increased, the 1 MB limitation became a significant problem. Intel intended to solve this limitation along with others with the release of the 286.

Read more about this topic:  Protected Mode

Famous quotes containing the word history:

    No one can understand Paris and its history who does not understand that its fierceness is the balance and justification of its frivolity. It is called a city of pleasure; but it may also very specially be called a city of pain. The crown of roses is also a crown of thorns. Its people are too prone to hurt others, but quite ready also to hurt themselves. They are martyrs for religion, they are martyrs for irreligion; they are even martyrs for immorality.
    Gilbert Keith Chesterton (1874–1936)

    The one duty we owe to history is to rewrite it.
    Oscar Wilde (1854–1900)

    So in accepting the leading of the sentiments, it is not what we believe concerning the immortality of the soul, or the like, but the universal impulse to believe, that is the material circumstance, and is the principal fact in this history of the globe.
    Ralph Waldo Emerson (1803–1882)