Dear all,
The final draft of my magnum opus about Personal Programming is now
ready for review:
http://folk.uio.no/trygver/themes/Personal/PP-019%20-%20Copy%20(17).pdf
The article's main theme is Personal Programming for everybody with
Loke, a personal object computer. Its first purpose is to
empower laypeople to take control over their corner of the Net with
its IoT. I have created a proof-of-concept implementation as a
non-intrusive extension of Squeak version 3.10.2, and have used it
to demonstrate how a novice uses the Loke IDE to create a small and
intuitive program.
The article describes the concepts behind Loke .The current Squeak
implementation should be ported to Pharo and can grow into the
preferred Pharo-based IDE for laypeople taking control over their
information environment.
I will appreciate your possible comments before Aug. 31.
Enjoy
--Trygve
The article's 43 pages has several high points, I have included one
of them here:
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C.7.We need a paradigm shift
The history of Western astronomy shows a series of paradigm
shifts from the geocentric paradigm with its stationary Earth as
the center of the Universe with its epicycles and other bizarre
explanations of what appeared to be essential complexities.
Astronomy evolved via the heliocentric to the current distributed
paradigm with its chunks of mass connected by gravity. What
appeared as essential complexity in one paradigm was easily
resolved in the next.
It is tempting to look for similar paradigm shifts in computing.
Mainstream programming has based much of its theory and practice
on the CPU-centric paradigm exemplified by the von Neumann
machine. A memory-centric paradigm came in 1960 with the Autokon
CAC/ CAM system and its central database (Reenskaug, 1973). The
solution was obvious, and there must have been many similar
initiatives without me being aware of them.
It is time to realize that the first two paradigms do not meet
our current challenges: We are plagued with immensely large,
complex, and insecure systems that long ago left the realm of
human understanding. A recent example: Customers found that their
bank charged them twice for the same transaction. Several weeks
after the problem was discovered, the bank publicly admitted that
they still didn't understand how the problem could arise: The
complexity of their system was clearly beyond human comprehension.
The bank has a staff of very competent experts, but they need a
better foundation for modeling and implementing their
sophisticated requirements.
Computers can transform, store, and communicate data, (Figure
below). The essence of the CPU-centric paradigm is that computers
are primarily used to transform data; they compute. The essence of
the memory-centric paradigm is that computers are used primarily
to store data; they organize applications around a shared
database. The essence of the communication-centric paradigm is
that computers are primarily used to exchange messages with other
computers to make them collaborate to achieve a common goal.
The three paradigms of computing
It is time to heed Tony Hoare's plea for simplicity and achieve a
better way of separating concerns. Mainstream programming should
shift to the communication-centric paradigm exemplified by the
object computer that is the foundation for this article.
The communication-centric paradigm has been on the horizon for
many years. I first met it in Prokon's idea of distributed
computers (Reenskaug, 1977), but there must have been many other
initiatives. A newer example is Service-Oriented Architectures
(SOA) that, in essence, is communication-centric. It didn't meet
with immediate success, possibly because people tried to apply it
within the CPU-centric paradigm where it doesn't belong. There are
many other examples such as distributed computing. And of course,
DCI and the IoT itself are, by definition, communication-centric.
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Locked
