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    SubjectRe: real-time threaded IO with low latency (audio)
    David Olofson <audiality@swipnet.se> wrote:
    > I think this whole discussion is beginning to get confused by different
    > definitions of "real time". (Not the first time...) Basically, there are
    > two kinds:
    >
    > 1) Soft real time
    > * Typically ms precision timing.
    > * No guaranteed deadlines.
    >
    > 2) Hard real time
    > * Usually significantly better than ms precision
    > * Guaranteed deadlines.

    Maybe three kinds, see: http://hegel.ittc.ukans.edu/projects/kurt

    <QUOTE>
    Some types of processing (eg. multimedia) do not fit well into the
    hard or soft real-time categories. The periodic requests made by
    multimedia applications are sensitive to variations in timing. As
    such, they are not well served by the loose guarantees provided by
    soft real-time systems. Hard real-time systems are often faced with
    providing guarantees at the expense of providing services. Thus, while
    they can meet the timing requirements of a multimedia application,
    many times they cannot meet it's other service requirements. For
    example, real-time processes running under RTLinux have no access to
    any of the Linux services.

    A purely binary distinction between hard and soft real-time is clearly
    not acceptable for all applications. Many applications have
    requirements spanning a continuum between the two. ...
    </QUOTE>

    [With supposedly a demo where a modified xanim performs better on a
    loaded system.]

    --
    Raul

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