Editing Grid computing (section)

==CPU scavenging==
'''CPU-scavenging''', '''cycle-scavenging''', or '''shared computing''' creates a “grid” from the idle resources in a network of participants (whether worldwide or internal to an organization). Typically, this technique exploits the 'spare' [[instruction cycle]]s resulting from the intermittent inactivity that typically occurs at night, during lunch breaks, or even during the (comparatively minuscule, though numerous) moments of idle waiting that modern desktop CPU's experience throughout the day ([[IO bound|when the computer is waiting on IO from the user, network, or storage]]). In practice, participating computers also donate some supporting amount of disk storage space, RAM, and network bandwidth, in addition to raw CPU power.{{Citation needed |date= July 2013}}

Many [[volunteer computing]] projects, such as [[BOINC]], use the CPU scavenging model. Since [[Node (computer science)|nodes]] are likely to go "offline" from time to time, as their owners use their resources for their primary purpose, this model must be designed to handle such contingencies.

Creating an '''Opportunistic Environment''' is another implementation of CPU-scavenging where special workload management system harvests the idle desktop computers for compute-intensive jobs, it also refers as Enterprise Desktop Grid (EDG). For instance, [[HTCondor]]<ref>{{cite web|url=https://research.cs.wisc.edu/htcondor/|title=HTCondor - Home|website=research.cs.wisc.edu|access-date=14 March 2018|archive-date=2 March 2018|archive-url=https://web.archive.org/web/20180302205500/http://research.cs.wisc.edu/htcondor/|url-status=live}}</ref> (the open-source high-throughput computing software framework for coarse-grained distributed rationalization of computationally intensive tasks) can be configured to only use desktop machines where the keyboard and mouse are idle to effectively harness wasted CPU power from otherwise idle desktop workstations. Like other full-featured batch systems, HTCondor provides a job queueing mechanism, scheduling policy, priority scheme, resource monitoring, and resource management. It can be used to manage workload on a dedicated cluster of computers as well or it can seamlessly integrate both dedicated resources (rack-mounted clusters) and non-dedicated desktop machines (cycle scavenging) into one computing environment.