Atomic clocks will only see a loss of 1 second in accuracy over a period of 10 million years. They are used in multiple ways, including the GPS in your car. Now researchers have found a way to bypass ...
Yahoo: Using atomic nuclei could allow scientists to read time more precisely than ever – what this research could mean for future clocks
Atomic clocks exploit the properties of atoms to create incredibly precise 'ticks.' Nate Phillips, NIST Most clocks, from wristwatches to the systems that run GPS and the internet, work by tracking ...
Using atomic nuclei could allow scientists to read time more precisely than ever – what this research could mean for future clocks
StudyFinds on MSN: If GPS goes dark, this atomic clock could keep the world running
This Portable Atomic Clock Maintained Accurate Time on a Rolling Ship at Sea In A Nutshell Australian physicists built a portable atomic clock precise enough to outperform the best commercial timing ...
If GPS goes dark, this atomic clock could keep the world running
For decades, atomic clocks have provided the most stable means of timekeeping. They measure time by oscillating in step with the resonant frequency of atoms, a method so accurate that it serves as the ...
Phys.org: Innovative optical atomic clock could combine single-ion accuracy with multi-ion stability
For many years, cesium atomic clocks have been reliably keeping time around the world. But the future belongs to even more accurate clocks: optical atomic clocks. In a few years' time, they could ...
I had a 25-hr debugging marathon in < 2 days and then wrote this answer here. See also the bottom of this question for more info. and documentation on 8-bit variables having naturally atomic writes and naturally atomic reads for AVR 8-bit microcontrollers when compiled with the gcc compiler which uses the AVR-libc library.
Which types on a 64-bit computer are naturally atomic in gnu C and gnu ...
Objects of atomic types are the only C++ objects that are free from data races; that is, if one thread writes to an atomic object while another thread reads from it, the behavior is well-defined. In addition, accesses to atomic objects may establish inter-thread synchronization and order non-atomic memory accesses as specified by std::memory_order.
22 Atomic vs. Non-Atomic Operations "An operation acting on shared memory is atomic if it completes in a single step relative to other threads. When an atomic store is performed on a shared memory, no other thread can observe the modification half-complete.
There are two atomic CAS operations in C++11: atomic_compare_exchange_weak and atomic_compare_exchange_strong. According to cppreference: The weak forms of the functions are allowed to fail spurio...
In addition (and more importantly), note that std::atomic must support all operations for all possible data types, so even if you declare a ten million byte struct, you can use compare_exchange on this.
When can 64-bit writes be guaranteed to be atomic, when programming in C on an Intel x86-based platform (in particular, an Intel-based Mac running MacOSX 10.4 using the Intel compiler)? For exampl...
So, this means that Richard Barry is saying that 4-byte reads and writes are atomic on these 32-bit microcontrollers. This means that he, at least, is 100% sure 4-byte reads and writes are atomic on STM32. He doesn't mention smaller-byte reads, but for 4-byte reads he is conclusively sure.
There are several questions on SO dealing with atomic, and other that deal with std::condition_variable. But my question if my use below is correct? Three threads, one ctrl thread that does prepar...
Are C/C++ fundamental types, like int, double, etc., atomic, e.g. threadsafe? Are they free from data races; that is, if one thread writes to an object of such a type while another thread reads fr...
The AVR-libc user manual in the
The definition of atomic is hazy; a value that is atomic in one application could be non-atomic in another. For a general guideline, a value is non-atomic if the application deals with only a part of the value. Eg: The current Wikipedia article on First NF (Normal Form) section Atomicity actually quotes from the introductory parts above.
compare_exchange_weak() is one of compare-exchange primitives provided in the std::atomic library introduced in C++11. It's weak in the sense that it could return false even if the value of the object is equal to expected. This is due to spurious failure on some platforms where a sequence of instructions (instead of one as on x86) are used to implement it. On such platforms, context switch ...
There is the proposal P1478R8: Byte-wise atomic memcpy, which covers my exact use case. This proposal suggests to add atomic_load_per_byte_memcpy and atomic_store_per_byte_memcpy to a new header bytewise_atomic_memcpy, which can copy bytewise using atomic semantics. How are sequence locks correctly implemented in C++ up to C++23?
What operations in Java are considered atomic? In Java, the reading and writing of 32-bit or smaller quantities are guaranteed to be atomic. By atomic, we mean each action takes place in one step and cannot be interrupted. Thus, when we have multithreaded applications, the read and write operations are thread-safe and need not be made synchronized. For example, the following code is thread safe:
Prefer more specific atomic types over atomic.Value. Just as atomic.Bool is preferred over atomic.Value when working with bool values, atomic.Pointer is preferred over atomic.Value when working with pointers. If my code considers using generics, can all atomic.Value's be converted to atomic.Pointer's and what are the cases where atomic.Value's should be used more? Convert from atomic.Value to ...
AtomicBoolean has methods that perform their compound operations atomically and without having to use a synchronized block. On the other hand, volatile boolean can only perform compound operations if done so within a synchronized block. The memory effects of reading/writing to volatile boolean are identical to the get and set methods of AtomicBoolean respectively. For example the compareAndSet ...