Topic: problems with the von Neumann architecture

topics > computer science > computer hardware > Group: machine model

computer as state machine
functional programming
state machine
von Neumann computer


The machine state of 'von Neumann' computers and associated languages is changed incrementally by locally determined information. Backus in his Turing award paper observes that incremental state changes require computing and communicating many addresses. He calls the channel between memory and the CPU the 'von Neumann' bottleneck, and proposes reduction machines as an alternative. Practical reduction machines may become possible with VLSI architecture in which the discrete components of 'von Neumann' computers are difficult to implement efficiently. (cbb 5/80)
Subtopic: von Neumann bottleneck up

Quote: the 'von Neumann bottleneck' is the channel between the CPU and memory [»backJ8_1978a]
Quote: languages should avoid the 'von Neumann' model of a global memory manipulated by sequential execution; bottleneck between control unit and memory [»ackeWB_1979]
Quote: in von Neumann architectures much of memory traffic is for finding data
Quote: in a von Neumann computer, most transistors do nothing most the time; only for memory [»hillWD_1985]
Quote: programming is basically planning and detailing the enormous traffic of words through the von Neumann bottleneck [»backJ8_1978a]

Subtopic: languages tied to memory, local state up

Quote: conventional programming languages are modeled on the 'von Neumann' computer [»backJ8_1978a]
Quote: the state of an Algol program is modified by an 'enormous cable' of specialized 'wires' for every statement type [»backJ8_1978a]
Quote: von Neumann languages provide an immense framework and limited changeable parts [»backJ8_1978a]
Quote: von Neumann languages must have their semantics closely coupled to the state; every computational detail changes the state
Quote: with 'von Neumann' languages can not modify the state as a whole [»backJ8_1978a]

Subtopic: abandon the model up

Quote: could increase usefulness of VLSI by abandoning the 'von Neumann' architecture

Related Topics up

Topic: computer as state machine (20 items)
Topic: functional programming (45 items)
Topic: state machine (67 items)
Topic: von Neumann computer
(14 items)

Updated barberCB 11/04
Copyright © 2002-2008 by C. Bradford Barber. All rights reserved.
Thesa is a trademark of C. Bradford Barber.