DI:17.8 DESIGN

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Design interfaces have been continuously improving over the years,

- ASCII Text Files

- Keyboard Entry, with printed output

- Keyboard Entry with graphic terminal output

- Icon and Menu Driven with on-screen graphics

- Fully windowed interfaces

As computers become cheaper, and more powerful, the only interfaces of real importance are the Graphical User Interfaces (GUI).

An example of novel technology is the visual scanner available for 3D input.

DI:17.8.1 Graphical User Interfaces

The current demands on user interfaces are,

- on-line help

- adaptive dialog/response

- feedback

- ability to interrupt processes

- consistent modules

- a logical display layout

- deal with many processes simultaneously

The common trend is to adopt a user interface which often have,

- Icons

- A pointer device (such as a mouse)

- Full color

- Support for multiple windows, which run programs simultaneously

- Popup menus

- Windows can be moved, scaled, moved forward/back, etc.

The history behind these machines are,

- Development of Mouse based graphical interface at Xerox Palo-Alto Research park (70s)

- Personal Computers began providing graphical programs for system management, games, etc (Early 80s)

- MacIntosh, Sun, Apollo, Silicon Graphics, and others introduced mouse driven, fully windowed computers (Mid 80s)

- MacIntosh Competitor IBM PC gets OS/2 and Microsoft Windows (Late 80s). Marking massive movement to Windowed environment by all players in scientific computing.

- X-Windows becomes a new, and widely accepted standard on workstations (Late 80s)

- Microsoft introduces Windows, bringing windowed interfaces to the last major computer platform.

Some Concepts in GUIs are,

button - An item which is shown within a window. When a user points at it, and presses a mouse button, it initiates an action.

icon - A small graphical symbol on the screen which can be opened to expose a window

menu - A pop up menu which stays hidden until called up by mouse. This simplifies problems of crowded screens.

mouse - a very popular input device for graphics programs. The use can point and choose an item. Contemporary alternatives are track-balls, joy-stick, dial boxes, tablets, etc.

scrollbars - At this side of some graphical, and text windows are bars which can be used to move the window around, to see previous text, or hidden areas of a graphics screen.

slider - A bar chart type of input, where the user can use the mouse to pull the slider along, and change an input value

window - A panel for keyboard and mouse I/O, which can be layered on a screen with other windows, like paper on a desk. The user often selects to work in a specific window by pointing the mouse into it. A Window may be closed, to become an icon

Popular window systems are (not a complete list),

OS/2 - IBMs attempt to take control of the operating system used on the IBM PCs, and bring full capability to PC architecture.

Windows 3.1 - Microsoft's answer to the MacIntosh interface

Windows 95 - Microsoft's answer to Windows 3.1 - adds a true multitasking environment.

Windows NT - Microsoft's answer to Windows 95 - adds more capable network and file security issues.

MacIntosh Interface - The proprietary windowed operating system, considered one of the forerunners in user friendly systems.

Sunview - The original windowed systems used on Sun computers

X-Windows - A defacto standard for newly developed windowed operating systems.

Openwindows - Sun's new windowed operating system which is a superset of X-Windows

Motif - A competitor to Openwindows, also based on the X-Windows standards

The Implications of X-Windows will be very important in future computer purposes. Some of the X-Windows Features are,

- intended for networking, including display of programs across a network. The implication of this is that I may sit at a Sun computer in my office, and run Ideas across the network from the SGI lab.

- Shared definitions makes software very portable between machines. (The quantity of public domain software is huge).

- The user interface is very similar when going between different X-Windows based machines.

- Easy to Customize for an individual user

- The differences between systems like Motif and Openwindows are mainly based on definitions of things like buttons, fonts, etc.

- When using X-Windows, a program (called the X server) runs which controls all the windowed graphics. Programs that use X are written to let it set up buttons, get input, call functions, etc.

- etc.

Windows NT is not yet as capable as X-Windows, but if the trend continues it will become more similar over time.

Automatic GUI generators are available on commercial systems. One example is given for a system which allows window layout, then automatic program generation.