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For many appls:
‰ it is sufficient that all machines agree on the same time.
‰ it is not essential that this time also agree with the real time
E.g. make example - it is adequate that all machines agree that it is 10:00
even if it is really 10:02.
Meaning: it is the internal consistency of the clocks that matters, not
whether they are particularly close to the real time.
For these algorithms it is conventional to speak of the clocks as
logical clocks.
„ Counter-ex:
when the additional constraint is present that the clocks
„ must not only be the same,
„ but also must not deviate from the real time by more than a certain amount,
the clocks are called physical clocks.
A physical clock measures time based on a physical oscillator like a quartz crystal. A logical clock is used in distributed systems to order events based on causality rather than real time, ensuring consistency even when clocks on different machines are not synchronized.
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What is the difference between physical and logical clock in synchronisation?
A physical clock is a hardware device that tracks time based on a physical phenomenon like the oscillation of a crystal, while a logical clock is an abstract mechanism for ordering events in a distributed system. Physical clocks can drift or have variability, while logical clocks rely on logical relationships between events. Synchronization using physical clocks aims to adjust for clock drift, while synchronization using logical clocks focuses on establishing a consistent ordering of events.
What is the difference between a watch and a clock?
A watch is typically worn on the wrist and is portable, while a clock is usually placed on a wall or a surface. Watches are designed to be carried around while clocks are stationary timepieces. Additionally, watches are often more compact and come in various styles, while clocks tend to be larger and more utilitarian.
What is difference between Stop watch and stop clock?
A stopwatch is typically a handheld device used for measuring time intervals, while a stop clock refers to a wall-mounted or stationary clock that can be stopped and started to measure time. Both devices can be used to accurately time events, but the design and portability differ between the two.
What is the difference between a wall clock and a mantle clock?
A wall clock is designed to be hung on a wall and typically has a simpler design with a larger face for easy visibility. A mantle clock is meant to be placed on a mantle or shelf, often has more decorative elements, and is usually smaller in size compared to a wall clock.
What type of clock was the first atomic clock?
The first atomic clock was a cesium atomic clock. It was developed in 1955 by Harold Lyons at the National Physical Laboratory in the United Kingdom.
What is the difference between physical and logical clock in synchronisation?
A physical clock is a hardware device that tracks time based on a physical phenomenon like the oscillation of a crystal, while a logical clock is an abstract mechanism for ordering events in a distributed system. Physical clocks can drift or have variability, while logical clocks rely on logical relationships between events. Synchronization using physical clocks aims to adjust for clock drift, while synchronization using logical clocks focuses on establishing a consistent ordering of events.
What is the difference between 12hr clock and 24 hr clock?
days
What is the difference in the 12 hour clock and the 24 hour clock?
The difference between 12 hour clock and a 24 hour clock is that when you say 1:00am for a 12 hour clock you would say 0100 hours
5 What it is the basic difference between a register and a counter?
register has the same clock. counter do not need to have the same clock.
Difference between Bus Clock and System Clock in Microcontrollers?
Bus Clock is based on the System Clock. In other terms Bus Clock is derived from system Clock. Bus Clock is usually half System Clock. (Busy Clock = System Clock / 2)
What is the difference between a wing and an airfoil?
the difference is that the wing is attached to the bussom of a bird and an airfoil is attached to the clock of the plane.
What is the difference between vector clock and lamport's logical clock?
Reading Vector Clock TimestampsCausally OR Concurrent:Events a and b are either causally related or they are concurrent. Definition: "event a" causes "event b" if and only if ta < tbwhere: ta < tb If and only if they meet two conditions:they are not equal timestamps ( there exists i, ta[i] != tb[i]) andeach ta[i] is less than or equal to tb[i] (for all i, ta[i]
What is a Rhythm Clock used for?
A Rhythm Clock works just like any other clock. It simply gives the time. The only difference between it and other clocks is that it is designed differently.
Drawbacks of Lamport logical clock?
Lamport's clock does'nt ensure that if L(e1)<L(e2) e1->e2
What is clock speed?
Here is a short explanation. Clock rate or clock speed is the speed at which a microprocessor (CPU) executes instructions. Clock speeds are typically expressed in megahertz (MHz) or gigahertz ((GHz). A single clock cycle (usually shorter than a nanosecond in modern non-embedded microprocessors) toggles between a logical zero and a logical one state. Sources: http://www.webopedia.com/TERM/C/clock_speed.html http://en.wikipedia.org/wiki/Clock_rate
What's the difference between a clock radio and an alarm clock?
A clock radio and an alarm clock are two very similar things which provide some of the same functions however they differ in their features. An alarm clock is a basic clock which has an alarm function and a clock radio combines the use of an AM/FM radio and an alarm clock.
Difference between system tick and processor clock?
Based on the Crystal used in the circuit, and the divisor selection, the processor clock frequency is obtained the tick time is the min clock cycles required to do a nop operation
