Atomic semantics is a type of guarantee provided by a shared by several processors in a parallel machine or in a network of computers working together.Atomic semantics are very strong. An atomic register provides strong guarantees even when there is concurrency and failures. A read/write register R stores a value and is accessed by two basic operations: read and write(v). A read returns the value stored in R and write(v) changes the value stored in R to v.A register is called atomic if it satisfies the two following properties: 1) Each invocation op of a read or write operation: •Must appear as if it were executed at a single point τ(op) in time. •τ (op) works as follow:τb(op) ≤ τ (op) ≤ τe(op): where τb(op) and τe(op) indicate the time when the operation op begins and ends. •If op1 ≠ op2, then τ (op1)≠τ (op2) 2) Each read operation returns the value written by the last write operation before the read, in the sequence where all operations are ordered by their τ values. Atomic/Linearizable register: Termination: when a node is correct, sooner or later each read and write operation will complete. Safety Property (Linearization points for read and write and failed operations): Read operation:It appears as if happened at all nodes at some times between the invocation and response time. Write operation: Similar to read operation, it appears as if happened at all nodes at some times between the invocation and response time. Failed operation(The atomic term comes from this notion):It appears as if it is completed at every single node or it never happened at any node. Example : We know that an atomic register is one that is linearizable to a sequential safe register. The following picture shows where we should put the linearization point for each operation: An atomic register could be defined for a variable with a single writer but multi- readers (SWMR), single-writer/single-reader (SWSR), or multi-writer/multi-reader (MWMR). Here is an example of a multi-reader multi-writer atomic register which is accessed by three processes (P1, P2, P3). Note that R. read → v means that the corresponding read operation returns v, which is the value of the register. Therefore, the following execution of the register R could satisfies the definition of the atomic registers:R.write(1), R.read→1, R.write(3), R.write(2), R.read→2, R.read→2. (Wikipedia).
The Atom B1 The Quantum Mechanical Picture of the Atom
The quantum mechanical model of the atom.
From playlist Physics - The Atom
The Atom B2 The Quantum Mechanical Picture of the Atom
The quantum mechanical model of the atom.
From playlist Physics - The Atom
The Atom B3 The Quantum Mechanical Picture of the Atom
The quantum mechanical model of the atom.
From playlist Physics - The Atom
Atomic Physics 1: Quantum Numbers
Video 1 on Atomic Physics which sets out the four quantum numbers, the Pauli Exclusion Principle, the order of filling electron shells and the ordering of elements in the Periodic Table.
From playlist Atomic Physics
Algebraic Expressions (Basics)
This video is about Algebraic Expressions
From playlist Algebraic Expressions and Properties
The Nuclear Shell Model: An Introduction
A basic introduction to the shell model to explain magic numbers in nuclei.
From playlist Nuclear Physics
An extension of the single particle model considering the consequence of pairing of nuclei and whether the nuclear characteristics are dependent on the lone unpaired nucleon.
From playlist Nuclear Physics
Atomic number, atomic mass, protons, neutrons and electrons: from fizzics.org
Atomic number and atomic mass together provide key information about an isotope of an element. The two numbers prefix the symbol, the one above giving the atomic mass and the one below the atomic number. The atomic number or proton number defines which element it is. By subtracting that fr
From playlist Atomic structure
Simplifying rational expression
Learn how to simplify rational expressions. A rational expression is an expression in the form of a fraction where the numerator and/or the denominator are/is an algebraic expression. To simplify a rational expression, we factor completely the numerator and the denominator of the rational
From playlist Simplify Rational Expressions (Binomials) #Rational
Kernel Recipes 2018 - Evolution and use of relaxed concurrency primitives - Will Deacon
Over the past few years, the kernel has grown a modern, sophisticated memory model which is exposed directly to the developer and provides portable concurrency primitives across the 20+ architectures supported by mainline. These low-level primitives have been used to construct high-perfor
From playlist Kernel Recipes 2018
Do As I Can, Not As I Say: Grounding Language in Robotic Affordances (SayCan - Paper Explained)
#saycan #robots #ai Large Language Models are excellent at generating plausible plans in response to real-world problems, but without interacting with the environment, they have no abilities to estimate which of these plans are feasible or appropriate. SayCan combines the semantic capabil
From playlist Papers Explained
Simplify a rational expression
Learn how to simplify rational expressions. A rational expression is an expression in the form of a fraction where the numerator and/or the denominator are/is an algebraic expression. To simplify a rational expression, we factor completely the numerator and the denominator of the rational
From playlist Simplify Rational Expressions (Binomials) #Rational
Lec 19 | MIT 6.033 Computer System Engineering, Spring 2005
Transactions and Consistency View the complete course at: http://ocw.mit.edu/6-033S05 License: Creative Commons BY-NC-SA More information at http://ocw.mit.edu/terms More courses at http://ocw.mit.edu
From playlist MIT 6.033 Computer System Engineering, Spring 2005