Xgrid: Apple's Distributed Computing Framework
In the early 2000s, Apple Inc. introduced a powerful way for users to harness the collective strength of multiple computers. Xgrid, developed by the Advanced Computation Group, is a proprietary grid computing program and protocol designed to turn a network of individual Macs into a unified computing cluster.
By utilizing distributed computing—a method where a large task is split across multiple computers—Xgrid allowed administrators to exploit previously unused computational power. This was particularly effective for calculations that could be easily divided into smaller, independent operations, such as generating complex Mandelbrot maps.
Key Facts
- Developer: Apple Inc. (Advanced Computation Group).
- Release Date: January 6, 2004.
- Final Release: October 4, 2012 (Version 10.7.5).
- OS Compatibility: Mac OS X 10.4 through 10.7.
- Core Function: Distributed computing via a proprietary protocol.
- Infrastructure: Built upon the BEEP (Blocks Extensible Exchange Protocol) framework.
How Xgrid Works
The Xgrid ecosystem operates through a coordinated relationship between a controller and various client nodes. The Xgrid controller acts as the job scheduler, managing the distribution and collection of data.
The Process of Job Distribution
- Job Initiation: An initiating computer sends a complete set of instructions, known as a job, to the controller.
- Task Splitting: The controller divides the job into smaller instruction packets called tasks.
- Node Execution: These tasks are transferred to all Xgrid-enabled computers (nodes) on the network.
- Result Assembly: Each node executes its assigned instructions and returns the results to the controller, which assembles them back into the final job result for the initiating computer.
To facilitate this, Xgrid uses a specialized communication protocol layered on a schema that interfaces with the BEEP infrastructure, a network application protocol framework. Any computer with the Xgrid service enabled is automatically discovered and added to the available processing pool.
Implementation and Availability
Apple made Xgrid highly accessible by pre-installing the client on all computers running Mac OS X 10.4 through 10.7. This allowed organizations to set up a computing cluster at virtually no cost. However, the Xgrid client was removed starting with Mac OS X 10.8.
While the client was widely available, Apple differentiated the management tools based on the OS version. The standard Mac OS X client provided minimalist command-line functions, whereas the Mac OS X Server version included a full GUI control panel and a comprehensive feature set. For developers, Apple provided an API to build more sophisticated tools on top of the basic command-line mechanism.
The architectural design of Xgrid was modeled after the Zilla program, which was distributed with the OpenStep API from NeXT, a company Apple had previously acquired.
| Feature | Details |
|---|---|
| Developer | Apple Inc. |
| Type | Distributed Computing |
| License | Proprietary EULA |
| Platform | Independent (within Mac OS X) |
| Supported OS Versions | Mac OS X 10.4 to 10.7 |
| Communication Framework | BEEP Infrastructure |
Frequently Asked Questions
What is Xgrid?
Xgrid is a proprietary grid computing program developed by Apple that allows multiple Mac computers to work together as a cluster to solve complex computational tasks.
Which versions of Mac OS X supported Xgrid?
The Xgrid client was pre-installed on Mac OS X versions 10.4 through 10.7. It was not included in Mac OS X 10.8.
What is the difference between a "job" and a "task" in Xgrid?
A job is the complete set of instructions sent by the initiating computer. A task is a smaller packet of those instructions created by the controller to be processed by individual nodes.
How did Xgrid discover available computers?
Xgrid automatically detected and added any computer on the network that had the Xgrid service enabled.
What was the relationship between Xgrid and NeXT?
Apple modeled the design of Xgrid on the Zilla program, which was part of NeXT's OpenStep API.