This unit contains employability skills. Elements and Performance Criteria Elements describe the essential outcomes of a unit of competency. Performance criteria describe the performance needed to demonstrate achievement of the element. Where bold italicised text is used, further information is detailed in the required skills and knowledge section and the range statement.
It would usually never make sense to have different mutexes for the same condition variable, but this classic example shows why it often certainly makes sense to have multiple condition variables using the same mutex. Monitor usage[ edit ] The proper basic usage of a monitor is: Critical section of code goes here To be more precise, this is the same pseudocode but with more verbose comments to better explain what is going on: Otherwise, the answer is: Please help improve it to make it understandable to non-expertswithout removing the technical details.
The classic solution is to use two monitors, comprising two condition variables sharing one lock on the queue: Its associated lock is also "queueLock".
We are holding queueLock. In this case, more than one condition is associated with the condition variable, such that the condition variable represents a weaker condition than the conditions being checked by individual threads. The condition variable represents threads that are waiting for the queue to be non-full and ones waiting for it to be non-empty.
However, doing this would require using notifyAll in all the threads using the condition variable and cannot use a regular signal. This is because the regular signal might wake up a thread of the wrong type whose condition has not yet been met, and that thread would go back to sleep without a thread of the correct type getting signalled.
For example, a producer might make the queue full and wake up another producer instead of a consumer, and the woken producer would go back to sleep.
In the complementary case, a consumer might make the queue empty and wake up another consumer instead of a producer, and the consumer would go back to sleep. Using notifyAll ensures that some thread of the right type will proceed as expected by the problem statement.
Here is the variant using only one condition variable and notifyAll: Locks and condition variables are higher-level abstractions over these synchronization primitives. On a uniprocessor, disabling and enabling interrupts is a way to implement monitors by preventing context switches during the critical sections of the locks and condition variables, but this is not enough on a multiprocessor.
On a multiprocessor, usually special atomic read-modify-write instructions on the memory such as test-and-set, compare-and-swapetc. These usually require deferring to spin-locking for the internal lock state itself, but this locking is very brief.
Here is an example pseudocode implementation of parts of a threading system and mutexes and Mesa-style condition variables, using test-and-set and a first-come, first-served policy. This glosses over most of how a threading system works, but shows the parts relevant to mutexes and condition variables: Sample Mesa-monitor implementation with Test-and-Set[ edit ] This section may be too technical for most readers to understand.
The details are beyond this scope. Again, the details of how this is done are beyond this scope. The original thread is now "sleeping". There are methods to increment V and to decrement P a private integer s. However, the integer must never be decremented below 0; thus a thread that tries to decrement must wait until the integer is positive.
We use a condition variable sIsPositive with an associated assertion of P.Project Base William Angliss Institute of TAFE La Trobe Street Melbourne Victoria Telephone: (03) Facsimile: (03) Product Details.
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ashio-midori.com Trainee Manual. Project Base William Angliss Institute of TAFE La Trobe Street Monitor and improve workplace operations Monitor efficiency and service levels on an Manage workplace operations Work Projects Written Questions Oral Questions.
Handout Monitor Work Operations 27may16 ELEMENTS PERFORMANCE CRITERIA Elements describe the essential outcomes. Performance criteria describe the performance needed to demonstrate achievement of the element.
1. Monitor and improve workplace operations. Monitor efficiency and service levels through close contact with day-to-day operations.
A database operation is a set of database tasks defined by end users or application code, for example, a batch job or Extraction, Transformation, and Loading (ETL) processing. You can define, monitor, and report on database operations.
A network operations center (NOC) is a central location from which network administrators manage, control and monitor one or more networks. The overall function is to maintain optimal network operations across a variety of platforms, mediums and communications channels.