drawing

n 1: an illustration that is drawn by hand and published in a

book or magazine; "it is shown by the drawing in Fig. 7"

2: a work produced by representing forms or objects on a

surface by means of lines; "he did complicated pen-and-ink

drawings like medieval miniatures"

3: the creation of artistic drawings; "he learned drawing from

his father" [syn: {draftsmanship}, {drafting}]

4: players buy chances and prizes are distributed according to

the drawing of lots [syn: {lottery}]

5: act of getting or draining something such as electricity or

a liquid from a source: "the drawing of water from the

well" [syn: {drawing off}]

6: the act of moving a load by drawing or pulling [syn: {draft},

{draught}]

Darwin

1. A general purpose structuring tool of

use in building complex {distributed systems} from diverse

components and diverse component interaction mechanisms.

Darwin is being developed by the Distributed Software

Engineering Section of the Department of Computing at

{Imperial College}. It is in essence a {declarative} binding

language which can be used to define hierarchic compositions

of interconnected components. Distribution is dealt with

orthogonally to system structuring. The language allows the

specification of both static structures and dynamic structures

which evolve during execution. The central abstractions

managed by Darwin are components and services. Bindings are

formed by manipulating references to services.

The {operational semantics} of Darwin is described in terms of

the {Pi-calculus}, {Milner}'s calculus of mobile processes.

The correspondence between the treatment of names in the

Pi-calculus and the management of service references in Darwin

leads to an elegant and concise Pi-calculus model of Darwin's

{operational semantics}. The model has proved useful in

arguing the correctness of Darwin implementations and in

designing extensions to Darwin and reasoning about their

behaviour.

{Distributed Software Engineering Section

(http://www-dse.doc.ic.ac.uk/)}. {Darwin publications

(http://scorch.doc.ic.ac.uk/dse-papers/darwin/)}.

E-mail: Jeff Magee , Naranker Dulay

.

2. {Core War}.

(1998-10-30)