Sun Microsystems 2 manual Scheduling the CPU, Default Policy

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Default Policy

The Java Wireless Client software supplies a default policy for how a MIDlet gains the foreground. It enables the user to switch to an application list screen at any time by pressing a hot key. By default, the hot key is the Home key found on many platforms. The application list screen shows a list of all running MIDlets. When the user brings up the application list, the MIDlet that had been in the foreground is moved into the background. The user scrolls through the application list and chooses the MIDlet to bring to the foreground.

Native code can request the application list to be shown by sending a SELECT_FOREGROUND_EVENT into the system. See the code in the file win32app_export.c for an example of how this event is generated in response to the pressing of the Home key. Use the same technique of sending a SELECT_FOREGROUND_EVENT to show the application list in response to some other external event.

Alternative Policies and Their Implementations

Policies for switching foreground applications are highly dependent on a device’s existing user interface. If your device already enables a user to switch between native applications in a particular way, use the same or similar policies for the Java Wireless Client software. Users expect consumer products, such as small devices, to be predictable, easy to learn, and easy to use. Making the policies of your Java Wireless Client software as similar as possible to the native policies users already know and use speeds acceptance of the new functionality. See the MIDP 2.0 Style Guide (Addison-Wesley, 2003) for more information.

Scheduling the CPU

The CPU is a shared resource that requires separate policy decisions. The foreground application has exclusive access to the display and the input mechanisms, but you can have a policy that enables it to share the CPU with the background applications. Your policy depends at least in part on the capabilities of your device.

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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 MIDletDefault Policy Scheduling the CPUAlternative Policies and Their Implementations 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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