Xgrid

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Xgrid
Developer(s)Apple Inc.
Initial releaseJanuary 6, 2004[1]
Final release
10.7.5 / October 4, 2012; 11 years ago (2012-10-04)
EULA[2]
WebsiteHomepage at the Wayback Machine (archived January 2, 2006)

Xgrid is a proprietary

Apple Inc.[3]

It provides

Mac OS X 10.8. The Xgrid controller, the job scheduler of the Xgrid operation, is also included within Mac OS X Server
and as a free download from Apple. Apple has kept the command-line job control mechanism minimalist while providing an API to develop more sophisticated tools built around it.

The program employs its own communication

protocol layered on top of a schema to communicate to other nodes. This communication protocol interfaces with the BEEP infrastructure, a network application protocol framework
. Computers discovered by the Xgrid system, that is computers with Mac OS X's Xgrid service enabled, are automatically added to the list of available computers to use for processing tasks.

When the initiating computer sends the complete instructions, or

tasks. The design of the Xgrid system consists of these small packets being transferred to all the Xgrid-enabled computers on the network. These computers, or nodes, execute
the instructions provided by the controller and then return the results. The controller assembles the individual task results into the whole job results and returns them to the initiating computer.

Apple modeled the design of Xgrid on the Zilla program, distributed with

GUI
control panel and a full set of features.

History

Zilla

Xgrid's origins can be traced back to

Mac OS X 10.4 Tiger in April 2005.[8]

Several organizations have adopted Xgrid in large international computing networks. One example of an Xgrid cluster is MacResearch's OpenMacGrid, where scientists can request access to large amounts of processing power to run tasks related to their research.[9][10] Another was the now defunct Xgrid@Stanford project, which used a range of computers on the Stanford University campus and around the world[11] to perform biochemical research.[12][13][14]

In a report covering the announcement,

Xserve G5's launch later that year.[16] InfoWorld commentator Ephraim Schwartz also predicted that Xgrid was an opening move in Apple's entry into the enterprise computing market.[17] [8]

Apple discontinued Xgrid with OS X 10.8 Mountain Lion,[18] along with dependent services such as Podcast Producer.[19][20]

Protocol

Xgrid Protocol

The Xgrid protocol uses the BEEP network framework to communicate with nodes on the network. The system's infrastructure includes three types of computers which communicate over the protocol:

  • The client, which submits calculation jobs to the controller
  • The controller, which segregates the jobs into tasks, and assigns these tasks to agents
  • The agents, which process their own allocated part of the calculation and return results to the controller, which returns them to the client.[21][8]

A computer can act as one or all three of these components at the same time. The Xgrid protocol provides the basic infrastructure for computers to

communicate, but is not involved in the processing of the specified calculation.[22] Xgrid is targeted towards time-consuming computations that can be easily segregated into smaller tasks, sometimes called embarrassingly parallel tasks.[23] This includes Monte Carlo calculations, 3D rendering and Mandelbrot maps.[22]

Within the Xgrid protocol, three types of

cluster: requests, notifications and replies. Requests must be responded to by the recipient with a reply, notifications do not require a reply, and replies are responses to sent messages. They are identified by their name, type (request/notification/reply) and contents. Each message is encapsulated in a BEEP message (BEEP MSG) and is acknowledged on receipt by an empty reply (RPY).[7]
Xgrid does not leverage BEEPs message/reply infrastructure. Any received message which requires a response merely generates an independent BEEP message containing the reply. The Xgrid messages are encoded as dictionaries of key/value pairs which are converted to XML before being sent across the BEEP network.

Architecture

The architecture of the Xgrid system is designed around a job based system; the controller sends agents jobs, and the agents return the responses. The actual computation that the controller executes in an Xgrid system is known as a job. The job contains all the files required to complete the task successfully, such as the input

directories, executables and/or shell scripts, the files included in an Xgrid job must be able to be executed either simultaneously or asynchronously, or any benefits of running such a job on an Xgrid is lost. Once the job completes, the controller can be set to notify the client of the task's completion or failure, for example by email. The client can leave the network while the tasks are running. It can also monitor the job status on demand by querying the controller, although it cannot track the ongoing progress of individual tasks.[24][8]

The controller is central to the correct function of an Xgrid, as this node is responsible for the distribution, supervision and coordination of tasks on agents. The program running on the controller can assign and reassign tasks to handle individual agent failures on demand. The number of tasks assigned to an agent depend on two factors: the number of agents on an Xgrid and the number of

processors in each node. The number of agents on an Xgrid determines how the controller will assign tasks. The tasks may be assigned simultaneously for a large number of agents, or queued for a small number of agents. When a node with more than one processor is detected on an Xgrid, the controller may assign one task per processor; this only occurs if the number of agents on the network is lower than the number of tasks the controller has to complete.[24]

Xgrid is layered upon the Blocks Extensible Exchange Protocol (BEEP), an

peer-to-peer networks. BEEP, in turn, uses XML to define profiles for communicating between multiple agents over a single network or internet connection.[25]

Xgrid agent software was available for Unix and Linux systems.[26]

Interface

Xgrid administration tool

While it is possible to access Xgrid from the command line, the Xgrid graphical user interface, a program bundled with

Mac OS X 10.4 Tiger installations but the GUI was reserved for users of Mac OS X Server. This decision limited the efforts of the computer community to embrace the platform. Eventually, Apple released the Mac OS X Server Administration Tools to the public, which included the Xgrid administration application bundled with Mac OS X Server.[27]

Despite the lack of a graphical controller interface in the standard (non-server)

Xgrid Admin tool is possible.[27] Some applications, such as VisualHub, provided Xgrid controller capability through their user interfaces.[28][29]

See also

  • Condor High-Throughput Computing System

Notes

  1. ^ a b c "Mac OS X Manual Page For xgrid(1)". Apple Inc. June 27, 2007. Archived from the original on July 25, 2008. Retrieved July 25, 2008.
  2. ^ "Mac OS X 10.5 SLA" (PDF). Apple Inc. March 9, 2005. Archived from the original (PDF) on May 12, 2008. Retrieved June 12, 2008.
  3. ^ a b Cohen, Peter (March 29, 2004). "Apple posts Xgrid intro". Macworld. Archived from the original on October 6, 2022. Retrieved May 14, 2023.
  4. ^ Norbury-Glaser, Mary (2006). "Build Your Own Supercomputer From Your Macs Laying Around: How to employ Tiger's Xgrid to build clusters and to contribute to grid/cluster projects". MacTech. Vol. 22, no. 1. Archived from the original on May 14, 2023. Retrieved May 14, 2023.
  5. ^ "Zilla - Computerworld Honours Program Archives". Archived from the original on July 16, 2011. Retrieved February 27, 2009.
  6. ISBN 978-0-7710-7914-6
    .
  7. ^ a b Côté, Daniel (June 21, 2004). "XGrid agent for Unix architectures". Simple. Archived from the original on March 10, 2008. Retrieved July 18, 2008.
  8. ^
    doi:10.1145/1151828.1151835 (inactive January 31, 2024).{{cite conference}}: CS1 maint: DOI inactive as of January 2024 (link
    )
  9. ^ Martellaro, John (February 13, 2007). "OpenMacGrid Computing Grid for Mac Users Announced". The Mac Observer. Archived from the original on August 30, 2008. Retrieved March 1, 2009.
  10. ^ Saunders, Grover (February 12, 2007). "OpenMacGrid creates distributed computing love-fest". Ars Technica. Archived from the original on August 24, 2009. Retrieved March 1, 2009.
  11. ^ Parnot, Charles (December 3, 2007). "Xgrid@Stanford - Home". Stanford University. Archived from the original on October 10, 2014. Retrieved July 25, 2008.
  12. ^ Parnot, Charles (December 3, 2007). "Xgrid@Stanford - Projects". Stanford University. Archived from the original on September 26, 2011. Retrieved July 25, 2008.
  13. ISBN 978-3-540-30510-1
    .
  14. ISBN 978-1-118-17748-8
    .
  15. ISSN 0741-8647
    . Retrieved October 16, 2008. (Subscription required)
  16. ProQuest 194358336
    . (Subscription required)
  17. ProQuest 194347451
    . (Subscription required)
  18. ISBN 978-1-4493-4367-5
    .
  19. ISBN 978-1-118-41781-2. Archived
    from the original on November 8, 2021. Retrieved May 16, 2023.
  20. ISBN 978-1-118-17748-8
    .
  21. ISBN 978-3-540-30510-1
    .
  22. ^ a b Côté, Daniel (January 7, 2004). "XGrid". Simple. Archived from the original on April 12, 2008. Retrieved July 18, 2008.
  23. ^ Gulker, Chris (January 15, 2004). "Xgrid: Grid computing for the rest of us?". Linux.com. Archived from the original on November 20, 2008. Retrieved July 26, 2008.
  24. ^ a b "Xgrid Programming Guide: How It Works". Apple Inc. October 31, 2007. Retrieved June 12, 2008.
  25. ^ "Mac OS X Server: Xgrid" (PDF). Technology Brief. Apple Inc. November 1, 2007. p. 2. Archived (PDF) from the original on March 19, 2009. Retrieved March 1, 2009.
  26. ISBN 978-0-596-55274-9
    .
  27. ^ a b Muir, Dylan (June 23, 2005). "10.4: Run an Xgrid with Tiger client". Mac OS X Hints. Archived from the original on August 24, 2007. Retrieved July 26, 2008.
  28. ^ "VisualHub offers Xgrid support". MacNN. June 7, 2006. Archived from the original on December 9, 2017. Retrieved July 26, 2008.
  29. ^ Chartier, David (June 7, 2006). "VisualHub - The universal video converter". Engadget. Retrieved May 14, 2023.

Further reading

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