Clocks and Time - Revision history

Suhridk: /* Intro */

2012-01-10T16:28:04Z

Intro

Suhridk at 13:25, 9 January 2012

2012-01-09T13:25:38Z

Suhridk: /* Intro */

2011-12-31T15:49:05Z

Intro

Suhridk: /* Intro */

2011-12-19T18:11:52Z

Intro

Suhridk: /* Intro */

2011-12-11T17:51:02Z

Intro

Suhridk: /* Intro */

2011-12-11T17:45:53Z

Intro

Suhridk: /* Intro */

2011-12-11T16:49:43Z

Intro

Suhridk: /* Intro */

2011-12-11T16:47:27Z

Intro

Suhridk at 16:27, 11 December 2011

2011-12-11T16:27:29Z

Suhridk: Created page with "= Intro = * Absolute Time - A specific time. e.g. 10AM. * Relative Time - A value expressed as relative to some other time value (usually the current value). e.g. 10000 millisec..."

2011-12-11T16:26:16Z

Created page with "= Intro = * Absolute Time - A specific time. e.g. 10AM. * Relative Time - A value expressed as relative to some other time value (usually the current value). e.g. 10000 millisec..."

New page

= Intro =

* Absolute Time - A specific time. e.g. 10AM.
* Relative Time - A value expressed as relative to some other time value (usually the current value). e.g. 10000 milliseconds.

[[Category:RealtimeJava]]

@@ Line 4: / Line 4: @@
 * Relative Time - Represents a time interval milliseconds + nanoseconds seconds long. It generally is used to represent a time relative to now.
 * Standard Java only has a wall clock - calendar time. But real time systems require:
-** A monotonic clock.
+** A monotonic clock: A monotonic clock that progresses at a constant rate and is not subject to the insertion of extra ticks to reflect leap seconds (as UTC clocks are). A constant rate is needed for control algorithms which want to executed on a regular basis.
-** A countdown clock.
+** A countdown clock: A countdown clock that can be paused, continued or reset.
 ** A CPU execution time clock - measures amount of CPU time consumed by a particular thread or object.

← Older revision		Revision as of 13:25, 9 January 2012
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	* However note that the inter arrival time (the release) is not guaranteed only the frequency is.		* However note that the inter arrival time (the release) is not guaranteed only the frequency is.

−	[[Category:~~RealTimeJava~~]]	+	[[Category:RealtimeJava]]

← Older revision		Revision as of 15:49, 31 December 2011
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	** The HighResolutionTime has a static waitForObject(Object, HighResolutionTime) method which is calls Object.wait() but with a HighResolutionTime parameter instead.		** The HighResolutionTime has a static waitForObject(Object, HighResolutionTime) method which is calls Object.wait() but with a HighResolutionTime parameter instead.
		+
		+	* Rational Time: Is a Relative Time type with an associated frequency. Used to represent the rate at which certain events occur.
		+	* A rational time with an interval of 1 second and a frequency of 100ms, will have an inter arrival time of 10ms.
		+	* However note that the inter arrival time (the release) is not guaranteed only the frequency is.

	[[Category:RealTimeJava]]		[[Category:RealTimeJava]]

← Older revision		Revision as of 18:11, 19 December 2011
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	** The HighResolutionTime has a static waitForObject(Object, HighResolutionTime) method which is calls Object.wait() but with a HighResolutionTime parameter instead.		** The HighResolutionTime has a static waitForObject(Object, HighResolutionTime) method which is calls Object.wait() but with a HighResolutionTime parameter instead.

−	[[Category:~~RealtimeJava~~]]	+	[[Category:RealTimeJava]]

@@ Line 9: / Line 9: @@
 * Time is supported through the HighResolutionTime abstract class. Three implementing concrete classes - absolute, relative and rational.
 * Clock is supported through an abstract Clock class.
 * HighResolutionTime offers conversion between absolute and relative time values.
@@ Line 54: / Line 55: @@
 </syntaxhighlight>
 [[Category:RealtimeJava]]

@@ Line 1: / Line 1: @@
 = Intro =
-* Absolute Time - A specific time. e.g. 10AM.
+* Absolute Time - Represents a specific point in time given by milliseconds plus nanoseconds past some point in time fixed by the clock. For the default real-time clock the fixed point is the Epoch (January 1, 1970, 00:00:00 GMT)
 * Relative Time - A value expressed as relative to some other time value (usually the current value). e.g. 10000 milliseconds.
 * Standard Java only has a wall clock - calendar time. But real time systems require:
 ** A monotonic clock.
 ** A countdown clock.
-** A CPU execution time clock.
+** A CPU execution time clock - measures amount of CPU time consumed by a particular thread or object.
 [[Category:RealtimeJava]]