Introduction
This site is primarily an
introduction to my
personal manifesto about a different real-time -- more
generally and broadly applicable, time-critical -- paradigm that (although
still a work in progress) has proven to be much more
effective than the traditional paradigm when building
dynamic large scale, complex –
and especially
distributed – real-time systems.
"The problem is never how
to get new, innovative thoughts into your mind, but how to
get old ones out."
-- Dee Hock,
The
Birth of the Chaordic Age
In my opinion (although I
believe it to be obviously true), the real-time computing
field is widely misunderstood in both the practitioner and
research communities –
especially by comparison with other
topics in science and engineering in general, and in
computer science and engineering in particular.
This
misunderstanding by practitioners is largely to blame for real-time computing
being more of an ad hoc craft than an engineering discipline
(much less a scientifically grounded one).
This misunderstanding by researchers is
due to their paucity of contact with actual non-trivial
real-time systems, and the academics' primary focus on doing
relatively easy analytical work on simple deterministic –
generally unrealistic –
systems so they can publish a lot.
Both of those communities are
also to
blame for real-time computing historically being confined to
a small niche, when actually it has much wider
applicability.
Traditional real-time
computing concepts and technologies are intended only for
simple, static, predominately periodic (synchronous)
device-level subsystems. They are ineffective or even
counter-productive for the large and
important
class of
complex, dynamic, asynchronous and mesosynchronous (neither
synchronous nor asynchronous) real-time computing systems. Mesosynchronous real-time computing is found at all levels
of enterprises - from the device level (e.g., in
multi-mode
phased array radars), to the platform level (e.g., in
surveillance and intelligence aircraft), to the mission level (e.g., netted
sensor-to-shooter control loops in
network-centric warfare).
More detail about example applications in my application
domain (military systems) is on the
Worked Examples pages.
"It must, in all
justice, be admitted that never again will scientific life
be as satisfying and serene as in days when determinism
reigned supreme. In partial recompense for the tears we must
shed and the toil we must endure is the satisfaction of
knowing that we are treating significant problems in a more
realistic and productive fashion."
-- Richard Bellman,
Adaptive Control Processes:
A Guided Tour, 1961
On this site you can also learn a
little about me and what I do at
MITRE. Most of my work researching,
developing, and applying distributed real-time concepts,
technologies, and standards to military systems is
classified, so unfortunately very little about it can appear
here. In addition, I led the Distributed
Real-Time Specification for Java,
contributed to the
Real-Time
Specification for Java, and co-authored the OMG
Real-Time
CORBA 1.2 (ne'e 2.0) specification.
This site also has
an unconventional page about resources related to real-time.
You may want to check my Changes
page (see the Site Updated link at the bottom of every page),
which lists all the relatively significant updates
to this site. To facilitate that, my Changes page has an
RSS
feed
(what's
that?), and a form in which you can enter an
email address to be notified when the Changes page
is updated. Each individual page also has its own
date and time stamp.
About
the clock on my home page.
People frequently
associate a clock image with real-time computing system
books, web sites, etc. It is appropriate to the extent
that a clock symbolizes time, which is a fundamental
aspect of time-critical resource management, applications,
and systems. But a clock also usually implies static
cyclic periodicity – a strong property that closely
corresponds to the nature of traditional real-time
computing in device-level subsystems. But static
cyclic periodicity definitely does not correspond to the
nature of more general, larger scale, more complex, more
dynamic, more asynchronous, time-critical computing
systems at higher levels of an enterprise (for example,
network-centric warfare). The distorted
clock image on my home page is intended to maintain the
concept of time, timeliness, and time-critical resource
management, while rejecting the notion
of static cyclic periodicity.

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