Sun Microsystems 2 manual Interrupting the User, Default User Notification Policies

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Interrupting the User

Although a good user interface permits a user to interrupt applications at any time, it does not do the same to the user. Instead, it interrupts the user only when necessary. Unnecessary feedback, confirmation messages, and error messages that require a user response are distracting. See the MIDP 2.0 Style Guide (Addison- Wesley, 2003) for more information.

Default User Notification Policies

The default policies of the Java Wireless Client software interrupt the user only when necessary. For example, the system does not allow a background application to interrupt the user and regain the foreground of its own accord. If a background application requests the display by trying to set the current screen with a screen other than an alert, the foreground application is not affected. If a background application requests the display by trying to set the current screen to an alert, the foreground application remains in place, but an icon is placed on the status bar to let the user know that a background application needs attention.

The system does not interrupt the user for notification of most failures. For example, if a MIDlet fails because of an internal problem, such as receiving an out-of-memory error, the applications task exits, but the other application tasks are unaffected. The system does not interrupt the user with a notification that the application has exited. It simply removes the failed application from its list of running applications.

The Push system of the Java Wireless Client software, too, only interrupts the user when a pushed message arrives for an application that is neither running, nor allowed to be automatically started. If the application’s user preferences require the user to give permission to start an application in response to the arrival of a pushed message or the firing of a Push alarm, then the Push system asks the user for permission. The user can also set the applications user preferences to permit the system to automatically start the application in response to the Push system. In this case, the Push system does not ask the user for permission.

32 Multitasking Guide • May 2007

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Contents Multitasking Guide Page Contents Glossary Index Code Samples Vi Multitasking Guide May Tables Viii Multitasking Guide May Preface Before You Read This GuideHow This Guide Is Organized Related DocumentationTypographic Conventions Used in This Guide AaBbCc123Accessing Sun Documentation Online Sun Welcomes Your CommentsIntroduction Multitasking Robustness Mechanisms Compared With PoliciesMultitasking Guide May Multitasking Safety Multitask Safety and Multithread Safety Global and Static Data Singletons Multitasking Safety Example Code Example 2-1Native API for a Microwave OvenTypical usage of this API is shown in Code Example Multithread Safety Code Example 2-5Using the Locking Mechanism Multitask Safety Code Example 2-7Migrating Initialization to Native Code Establishing Per-Task Context Code Example 2-8Keeping State in Java Code Code Example 2-9Implementing the Native ncook Method Kniexport Knireturntypeint Multitasking Safety Multitasking Guide May Managing Native Resources Resource Management Mechanisms ReservationLimit Default Resource Allocation Policies RevocationCustomization of Resource Allocation Policies Maximum number of tasks isolates allowed Managing Native Resources Multitasking Guide May Other Multitasking Issues Switching the Foreground MIDletAlternative Policies and Their Implementations Default PolicyScheduling the CPU Default CPU Scheduling Policy Default User Notification Policies Interrupting the UserGlossary Java Community ProcessTM Jcptm Glossary Sun Java Device Test Index Multitasking Guide May
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Sun Microsystems, founded in 1982, was a significant player in the computing industry, best known for its innovative technology solutions and workstations, particularly the Sun-4, which represented a key milestone in the company's history. The Sun-4 architecture, launched in 1987, utilized the SPARC (Scalable Processor Architecture) RISC processor, notable for its high performance and scalability.

One of the primary features of Sun Microsystems' platforms was their ability to efficiently handle multitasking and resource management, making them ideal for enterprise-level applications and development environments. Sun-4 workstations boasted impressive graphics capabilities with the addition of advanced graphical user interfaces, support for color displays, and the SUNVIEW windowing system, which enhanced user experience and productivity.

The Sun-4 systems also supported the SunOS operating system, which was based on UNIX. This operating system was engineered for stability and robustness, offering features like multiuser support, networked environments, and advanced security options. Moreover, SunOS provided seamless integration with various programming languages, including C and C++, facilitating software development that aligned with industry standards.

Another standout characteristic of Sun Microsystems was its commitment to open systems and standards. By providing developers with comprehensive tools and environments, such as the Standardized Application Programming Interface (API) and support for networking protocols, Sun facilitated interoperability among different computing platforms. The emphasis on open architecture also meant that customers could easily upgrade their systems without being locked into proprietary solutions.

Sun Microsystems was also ahead of its time with innovations in network computing. Their workstations were among the first to support network file systems and distributed computing concepts, enabling seamless data sharing across multiple systems. With the introduction of the Network File System (NFS), Sun revolutionized how data was accessed and managed across networks, which played a significant role in the evolving landscape of client-server computing.

In summary, the Sun Microsystems 2 and its successive innovations in workstation technology highlighted the company's forward-thinking approach. By integrating powerful performance with open systems, robust operating systems, and advanced networking capabilities, Sun laid the groundwork for modern computing, influencing various sectors from academia to enterprise solutions. Even after its acquisition by Oracle in 2010, the legacy of Sun Microsystems continues to be felt across the computing industry.
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