Expansion Slots - History

History

Even vacuum-tube based computers had modular construction, but individual functions for peripheral devices filled a cabinet, not just a printed circuit board. Processor, memory and I/O cards became feasible with the development of integrated circuits. Expansion cards allowed a processor system to be adapted to the needs of the user, allowing variations in the type of devices connected, additions to memory, or optional features to the central processor (such as a floating point unit). Minicomputers, starting with the PDP-8, were made of multiple cards, all powered by and communicating through a passive backplane.

The first commercial microcomputer to feature expansion slots was the Micral N, in 1973. The first to establish a de facto standard was the Altair 8800, developed 1974-1975, which later became a mulit-manufacturer standard, the S-100 bus.Many of these computers were also passive backplane designs, where all elements of the computer, (processor, memory, and I/O) plugged into a card carge which passsively distributed signals and power between the cards.

Proprietary bus implementations for systems such as the Apple II co-existed with multi-manufacturer standards.

Read more about this topic:  Expansion Slots

Famous quotes containing the word history:

    Indeed, the Englishman’s history of New England commences only when it ceases to be New France.
    Henry David Thoreau (1817–1862)

    The history of literature—take the net result of Tiraboshi, Warton, or Schlegel,—is a sum of a very few ideas, and of very few original tales,—all the rest being variation of these.
    Ralph Waldo Emerson (1803–1882)

    Literary works cannot be taken over like factories, or literary forms of expression like industrial methods. Realist writing, of which history offers many widely varying examples, is likewise conditioned by the question of how, when and for what class it is made use of.
    Bertolt Brecht (1898–1956)