Reprinted from Byte, issue 5/89, pp. 230-231. This is a sidebar from a longer article.
A consistent graphical interface has been one of the industry’s most obvious
and controversial problems – until now. The Open Software Foundation (Cambridge,
MA) recently announced OSF/Motif, its first product offering.
|Photo 1: An example of an OSF/Motif display. OSF/Motif combines the utility of DECs XUI with the familiar look of Microsoft PM and the elegance of Hewlett-Packard’s New Wave. (Photo courtesy of Kee Hinkley and Apollo Computer.)
OSF/Motif is a graphical user-interface toolkit, window manager, style guide,
and user-interface language. It lets you create consistent graphics-based applications
on both open and proprietary systems. The various elements that constitute Motif were chosen
from vendor submissions to OSF.
Motifs interface behavior is compatible with Presentation Manager’s behavior. Thus,
if you’re familiar with PM on personal computers, you can use Motif-based applications
without learning a different user interface.
X marks the spot
Motif’s graphical interface is based on the X Window System from MIT. This
underlying technology provides you with a network-based graphical user interface.
X Windows has a server-client architecture. The actual application runs on the
client side and can be anywhere in the network – on a Cray, a VAX, a
specialized database processor, an Apollo workstation, and so on. The server runs
locally on the workstation, personal computer, or X terminal.
Using the X protocol, the client and server communicate, making it possible
to run a simulation on a Cray in the network while all user interaction and
graphical presentation appear on your workstation or personal computer.
Motif is composed of a style guide, window manager, interface toolkit, presentation
description language and compiler, user documentation, application programmer
documentation, and test applications.
|Style guide. The success of the Macintosh is attributed largely to the
consistent look and feel of the applications that run on it. This consistency is
what OSF, through Motif, hopes to bring to applications written by the rest of
the computer industry.
The style guide, a joint Hewlett-Packard/Microsoft submission, describes a
standard behavior and a set of conventions for applications, to ensure a consistent feel on
multiple applications. It is compatible with Microsoft PM, which is already familiar to many
PC users. The style guide includes extensions for powerful network-based workstations.
Its “look” is based on the HP three-dimensional screen-button appearance
(see photo 1).
|Window manager. An HP submission, the window manager lets you manipulate
multiple applications on the screen and plays a principal role in enforcing the
style guide. Although it provides standard PM behavior, the window manager is highly
customizable; it lets you redefine the contents of the window-manager menus and
alter other aspects of window-related interactions.
|Interface toolkit. The OSF/Motif toolkit, a DEC submission, is based on the
X Windows intrinsics, a toolkit framework provided with MIT’s X Window
System. The intrinsics use an object-oriented model to create graphical objects
known as widgets or gadgets. The specified widgets maintain consistency
DEC’s toolkit (XUI) will be extended to support the three-dimensional appearance
and PM behavior of the HP/Microsoft submission. It will be upwardly compatible with
the current Digital Application Programmer Interface so that applications written today
on XUI will move easily to OSF/Motif.
|Presentation description language. This language, using DEC’s User
Interface Language (UIL) compiler and resource manager, enables application developers
to describe the presentation characteristics of the application interface independent
of the actual application code. The separation between application and interface
lets you make many changes to the overall appearance and layout of an application
without having to modify, recompile, or relink the application itself.
OSF/Motif supports the major goals of the OSF by providing an interoperable, scalable,
and portable application environment. Let's look at these features.
Interoperable systems are more than just networked computers sharing CPU cycles,
memory, disk space, and I/O devices. In addition to sharing computer resources,
users need to move freely between applications running on different computers and
operating systems without having to learn a new user interface.
Many people believe that computing in the future will be dominated by personal
computers on the desktop and Unix-based systems in the network. A typical user
will run PM-based applications and network-based applications through an X server on
the same personal computer at the same time. OSF/Motif, with its PM behavior,
will let you do this without confusion – a major step toward linking the personal
computer and open-systems communities.
Scalability allows both users and applications to run on a wide range of hardware,
from personal computers to supercomputers. Today, when your application outgrows your
computer’s architecture and you move to a larger system, you usually need to
relearn your application. In fact, you may not be able to use it at all. Motif
is the first step toward allowing you and your application to scale to a
more powerful, yet still familiar, environment.
Motif is built on standards such as POSIX, ANSI C, and X Windows, so it is
portable to many different architectures. For example, within one day of receiving the
DEC and HP code, the OSF had the software running on three different hardware platforms.
A joint effort
OSF chose to build Motif from two technologies. This decision allows Motif to have PM
behavior and an advanced three-dimensional look implemented on the best toolkit available.
A joint team of OSF, DEC, and HP engineers is combining the two technologies.
Motif’s release is scheduled for this summer.