NetPlane Core Services

Global Lock Service

 

 

2.5.4.1.1Event Distribution Server

The Event Distribution Server (EDS) is an NCS process on the System Controller blade which handles the distribution of events based on client subscriptions and filtering mechanisms. If an event was posted and event persistence was specified, the event will be retained by the server process for the time period specified in the call. During the retention time period, the EDS may redistribute the event to new subscribers for that event. Events are distributed based on a match against the filter settings specified by the subscribed client and a priority specified in the event header.

There is an active and a stand-by EDS running respectively on the two system manager nodes. EDS uses the NCS Message based Checkpoint Service to keep the two synchronized and available for failover situations.

2.5.4.1.2Event Distribution Agent

This is a library that makes the EDSv APIs available to applications. The APIs themselves are all described in the respective SAF documents.

2.5.5Global Lock Service

The Global Lock Service (GLSv) implements the SAF Lock Service API.

2.5.5.1Basic Functionality

The GLSv provides a distributed locking service which allows applications running on multiple nodes to coordinate access to shared resources.

Locks are created and destroyed by applications as needed. Participating applications know that the locks exist and know how to use them. Access policies are outside the scope of the GLSv, which only provides the locking mechanism.

The GLSv supports exclusive and shared access modes. Exclusive access mode means that only one requestor is allowed through the lock at a time. Shared access mode means that multiple requestors are allowed through a lock at a time.

The GLSv furthermore supports synchronous and asynchronous APIs to carry out locking operations. In addition, GLSv provides an internal mechanism which ensures deadlock detection and prevention.

If an application creates a lock and then exits without unlocking, orphan locks are the result. Orphan locks are managed until they are properly purged from the system.

2.5.5.2Architecture

The GLSv consists of the following subparts:

zGlobal Locking Director

zGlobal Locking Node Director

zGlobal Locking Agent

32

NetPlane Core Services Overview User’s Guide (6806800C08B)

Page 32
Image 32
Motorola 6806800C08B manual Global Lock Service, Event Distribution Server, Event Distribution Agent

6806800C08B specifications

The Motorola 68000 microprocessor, particularly the revision marked as 68000C08B, stands out as a seminal component in the evolution of computing technology. Introduced in 1979, the 68000 architecture laid the groundwork for many advanced systems, influencing a multitude of platforms, from personal computers to game consoles.

The Motorola 68000C08B features a 16-bit data bus and a 24-bit address bus, allowing for a memory addressing capability of up to 16 MB. This architecture was pioneering for its time, enabling more extensive and complex software applications than its predecessors. The C08 revision particularly emphasized optimizing power consumption while maintaining performance, making it ideal for embedded systems and portable devices.

One of the 68000's key characteristics is its unique register set, which allows for a versatile range of operations. It consists of 8 general-purpose data registers and 8 address registers. The architecture supports both integer and floating-point operations, thanks to an integrated instruction set that facilitates complex mathematical computations, crucial for applications in graphics and gaming.

In terms of performance, the 68000 processor operates at clock speeds ranging from 8 MHz to 16 MHz, depending on the specific variant. The instruction set architecture (ISA) is known for its orthogonality, meaning that most instructions can be used interchangeably across different registers. This design simplicity allows for efficient coding and faster execution times, a significant advantage for developers.

Another remarkable feature of the 68000C08B is its capability for multitasking and improved context switching. Its advanced memory management, combined with support for virtual memory in later implementations, catered to the needs of operating systems and real-time applications, making it suitable for both consumer electronics and industrial machinery.

The Motorola 68000 family also supports a variety of peripherals, enhancing its flexibility as a microcontroller. This compatibility allowed manufacturers to create diverse product lines, from keypads and mice to modems and hard drives.

In summary, the Motorola 68000C08B microprocessor not only advanced the landscape of computer technology in the late 20th century but also helped set the stage for future innovations through its architecture, performance capabilities, and versatility in numerous applications. Its legacy continues to influence modern computing paradigms, ensuring the 68000 remains an essential chapter in the history of microprocessors.