Modern personal computer operating systems allow users to conveniently and efficiently perform all permissible operations on resources through visual direct manipulation including deleting objects, adding new objects, modifying existing objects, and changing objects' attributes.

The integration of resources that makes such ease of use possible is a direct benefit of modern personal computer operating systems.

To achieve a similar integration of resources distributed throughout the Internet, it would be desirable to have an Internet-distributed unifying operating system, however, considering the variety of systems and applications, complete integration by such a system is not a practical solution.

What is needed, is an alternative Internet operating system for a web-based desktop environment.

Other systems have addressed this problem, but in restrictive or incomplete ways.

Lotus Notes.TM. for example, is a system that provides a complete user environment for distributed resources, however it is restricted to Notes applications and cannot integrate generic Web-based applications.

There are a number of recently implemented systems that are more web oriented, such as DocuShare, Instant TeaRoom, and eRoom, however those systems offer only a subset of desktop functions including certain file operations.

Furthermore, rather than achieving an individualized, per-user, integration, those systems integrate on a per-group basis to create shared resource sets, in contrast to the individualized desktops enjoyed by personal computer users.

There exists a need for a system that can integrate applications and resources distributed over the Internet, to create a unified virtual computing environment similar to those which modern desktop operating systems create for local resources.

Whereas with the local desktop versions of those applications the user may easily select an e-mail message and indicate that it is to be faxed, this action would not be possible for the web-based applications without a special cooperation between the two applications.

The reason for this is that web-based applications do not have a common means of resource management.

Similarly, there exists a need for an authentication service to automatically authenticate users registered with each of the web sites providing services such as the e-mail and fax applications, in contrast to the current practice of requiring users to authenticate themselves to each application.

The object of this invention is to provide a web-based operating system that gives its users general access to arbitrary resources distributed throughout a public network of computers, specifically the Internet.

The object is achieved using the same or similar visual techniques of direct manipulation that are commonly provided in modern personal computing operating systems.

The users of the system have their own web-based data storage subsystems and file management tools that allow them to register web-based applications, set preferences and profiles, run applications, share files and folders to provide full interactivity as they would do on a desktop machine running a particular operating system.

The invention increases the flexibility of the Internet by introducing means for integration of data, applications and resources dispersed over the network.

It consists of a software module hereinafter referred to as "WebTop" which executes on the user's client workstation, and a software module hereinafter referred to as "WebBase" which executes on a Web server and responds to various WebTop requests.

The function of the WebTop is to provide a graphical user interface through which users may perform common "desktop" operations, such as invoking applications, copying files, and setting sharing attributes of files, and translate them to the operations that are appropriate for the resources that are the target of the request.

For example, selecting a Web server hosted file and dragging it into another folder may be translated as HTTP PUT and DELETE methods.

The WebTop may also provide an API so that applications aware of the WebTop, can perform the same set of functions as available through a GUI.

The WebBase serves as a general-purpose attribute store or registry to keep the persistent state needed by the WebTop and other applications, including users preferences, application-invocation information, and application settings and any other attribute-type information.

Improved techniques for condensing or reducing animated image data streams are disclosed.

The improved techniques enable the transmission and storage of animated images in a rapid and efficient manner.

Animated images are normally stored as image files that include a series of images which produce an animation effect when sequentially displayed.

For example, animated image files are often used by Internet sites to provide animation to their web pages.

In the case of a proxy server for a network (e.g., the Internet) that caches images, the condensing or reducing of the animated image files is particularly helpful because it not only to reduces image storage space but also accelerates the delivery of these animated images to end users.

The improved techniques are particularly well suited for use in reducing or condensing animated GIF images.

The present invention relates to graphical images and, more particularly, to condensing graphical images that are animated.

Graphic images are often stored as image files in a variety of different formats.