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Graph Based Protocol

It impose partial ordering on the set D ={d1, d2, d3, …, dn} of all data items. If di -> dj , then any transaction accessing both di and dj must access di before accessing dj it implies that the set D may now be viewed as directed acyclic graph. Back To Top

Lock Based Protocol 2

Lock Based Protocol
A lock is a mechanism to control concurrent access to a data item. Data items can be locked in two modes 1. Exclusive(X) mode: Data item can be both read as well as written. X-lock is requested using lock-x instruction. 2. Shared(S)-mode: Data item can only be read. S-lock is requested using lock-s instruction Lock ...

Concurrency Control

Concurrency control in Database management systems ensures that database transactions are performed concurrently without violating the data integrity of the respective databases. Thus concurrency control is an essential element for correctness in any system where two database transactions or more, executed with time overlap, can access the same data, e.g., virtually in any general-purpose database ...

Cache Memory

A cache is a component that transparently stores data so the future requests for the data can be served faster.The data that is stored within a cache, might be values that have been computed earlier or duplicates of the original values that are stored elsewhere. Cache Hit, Cache Miss If requested data is contained in ...

Addressing Modes 1

Various Addressing modes as used in Computer Architecture: Register ADD R1,R2 ,R3 means : R1 comments : used when a value is in register Immediate ADD R1, R2 , 1 means : R1 comment : used when a constant is needed Direct ADD R1 , R2 , (100) means : R1 comment : used to ...

Mathematical Logic – Introduction

Mathematical Logic - Introduction
What is it?? It is a foundation which gives precise meaning to mathematical statements. It is the basis on which proofs and arguments rest (well, we are not referring to those court room arguments for sure. However, even those, we believe, could be expressed in terms of Mathematical Logic).   INTRODUCTION The basic building blocks ...