Sun Labs Lively Kernel
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Note: The Lively Kernel runs best in
the Safari 3 web browser. With all the other web browsers, you
may still experience bugs and unusual behavior.
Update (May 2, 2008): The latest development
versions of the Lively Kernel are now available on
http://livelykernel.sunlabs.com/.
Refer to technical documentation
for details.
Update (February 8, 2008): Version 0.8.1
of the Lively Kernel is now available.
A new technical report is also available.
The Sun Labs Lively Kernel is a new web programming environment
developed at Sun Microsystems Laboratories. The Lively Kernel supports
desktop-style applications with rich graphics and direct manipulation
capabilities, but without the installation or upgrade hassles that
conventional desktop applications have. The system is written
entirely in the JavaScript programming language, a language supported
by all the web browsers, with the intent that the system can run
in commercial web browsers without installation or any plug-in components.
The system leverages the dynamic characteristics of the JavaScript language
to make it possible to create, modify and deploy applications on the fly,
using tools built into the system itself. In addition to its
application execution capabilities, the Lively Kernel can also
function as an integrated development environment (IDE), making
the whole system self-sufficient and able to improve and extend itself dynamically.
The main goal of the Lively Kernel is to bring the same kind of simplicity, generality and flexibility to web
programming that we have known in desktop programming for thirty years,
but without the installation and upgrade hassles than conventional
desktop applications have.
The Lively Kernel places a special emphasis on treating web applications
as real applications, as opposed to the document-oriented nature of
most web applications today. In general, we want to put programming
into web development, as opposed to the current weaving of HTML, XML
and CSS documents that is also sometimes referred to as programming.
A key difference between the Lively Kernel and other systems in the same area
is our focus on uniformity. Our goal is to build a platform
using a minimum number of underlying technologies. This is in contrast
with many current web technologies that utilize a diverse array of
technologies such as HTML, CSS, DOM, JavaScript, PHP, XML, and so on.
In the Lively Kernel we attempt to do as much as possible using a
single technology: JavaScript. We have chosen JavaScript primarily
because of its ubiquitous availability in the web browsers today
and because of its syntactic similarity to other highly popular
languages such as C, C++ and Java. However, we also want to leverage
the dynamic aspects of JavaScript, especially the ability to modify
applications at runtime. Such capabilities are an essential ingredient
in building a malleable web programming environment that allows
applications to be developed interactively and collaboratively.
The Lively Kernel runs in
supported web browsers without installation
or any plug-in components whatsoever.
The system utilizes the JavaScript engine, graphics capabilities
and asynchronous networking features that are already available
in commercial web browsers today. In general, one of our goals
has been to leverage existing technologies as much as possible.
A unique feature of the Lively Kernel is a graphics
library called Morphic. Morphic is a user interface
framework that supports composable graphical objects,
along with the machinery required to display and animate these
objects, handle user inputs, and manage underlying system resources
such as displays, fonts and color maps. A key goal of Morphic
is to make it easy to construct and edit interactive graphical objects,
both by direct manipulation and from within programs.
The Morphic user interface framework was originally developed for the
Self system
at Sun Labs, but it later became popular also as part of
the Squeak Smalltalk programming
environment.
The Lively Kernel brings the flexibility and power of Morphic
also to JavaScript developers and to web application development in general.
The main features of the Lively Kernel include:
-
Small web programming environment and computing kernel,
written entirely with JavaScript. In addition to its application
execution capabilities, the platform can also function as
an integrated development environment (IDE), making the
whole system self-contained and able to improve and
extend itself on the fly.
-
Programmatic access to the user interface. Our system provides
programmatic access from JavaScript to the user interface via the
Morphic user interface framework. The user interface is built around
an event-based programming model familiar to most web developers.
-
Asynchronous networking. As in Ajax, you can use asynchronous HTTP
to perform all the network operations asynchronously, without
blocking the user interface.
The Lively Kernel allows you to do pretty much everything
that you would expect to do in a conventional desktop
programming environment. The main difference is that
in the Lively Kernel everything takes place in a web browser.
Utilizing the features described above, you can build conventional,
desktop-style applications that run on the web. Utilizing the
capabilities of the Morphic user interface framework, you can
also build desktop-like environments and systems in which numerous
applications and widgets run simultaneously in a regular web browser.
The Sun Labs Lively Kernel is alive on the web, meaning that you do not
download it or install it. If your browser supports the Lively Kernel
(see the list of supported web browsers below),
then merely clicking on the Enter Lively Kernel link causes the
system to come to life in your computer. You may see some static elements
on the screen but, by default, everything there is alive and changeable.
The entirety of the Lively Kernel is written in JavaScript, a dynamic language
that uses no binary files for execution. The Lively Kernel does not require any
installation or plug-ins, since the necessary JavaScript engine is already
part of your web browser. As soon as you click on a link to start the system,
all the Lively Kernel code is loaded into your browser and running.
At some point we may compress the files to make for faster startup but,
if so, we will still make the full uncompressed sources available on this site.
For your convenience, we have made the source code available here as a
ZIP file.
The Lively Kernel is intended to run in every commercial web browser client
with no plug-ins or installation whatsoever. However, because of differences
in the underlying graphics and other capabilities of various web browsers,
we only support a limited set of browsers and browser versions.
We have tested our system on Windows XP and MacOS
using the following browsers:
- Safari 3 (recommended for best performance and quality of experience)
- Firefox 3 (still some bugs left)
- Firefox 2 (still various bugs left)
The browsers above provide support for
Scalable Vector Graphics (SVG),
a graphics library that we use as the underlying low level graphics interface.
The SVG interfaces are hidden from the application developer,
but our implementation requires an SVG-compatible graphics engine.
To end users and developers, the Lively Kernel is an environment that
is based purely on JavaScript, not SVG.
IMPORTANT! The Lively Kernel requires SVG support and does not
currently run on Microsoft Internet Explorer. We are hoping to have support
for Microsoft Internet Explorer available soon.
The following research papers provide further information about the project
and its background:
Videos:
Visit the forums to find out what people want and what they are
working on. If you produce a bug fix or enhancement, post it
on a forum to share it, and submit it to us to proffer
it for inclusion in future releases.
The Sun Labs Lively Kernel is research software. It may be remarkable in
various ways, but it is not production software.
Rather, it is an experimental system for turning the web as we know it
into a universe of objects that are active, accessible, changeable;
in short, lively.
We are making the Lively Kernel available as open source software to
encourage further exploration by academics and adventurous developers,
and we anticipate rapid progress toward future versions of the system
that are not only lively but also well-behaved.
The Sun Labs Lively Kernel is the result of a cooperation between four
experienced software developers, all frustrated with the state of
the web programming practice today:
While developing the Lively Kernel, we have received help from various
other people. We would especially like to thank Mikko Kuusipalo,
Kristen McIntyre, Richard Ortiz, Pekka Reijula, and Stephen Uhler
for their valuable contributions. We would also like to thank
Linda Bohn and Mario Wolczko for their invaluable assistance
during the project.
The idea of the Lively Kernel was inspired in part by the success
of the Squeak Smalltalk
programming environment. In this regard, we owe a debt to all
the people who designed that system. The specific choice of a
Morphic-style graphics architecture was inspired by the simplicity
of such an architecture manifested originally in
the Self system
and later in the Squeak system. For historical references,
refer to the following documents: