A brief introduction to Process synchronization in Operating Systems with classical examples and solutions using semaphores. A good starting tutorial for beginners.
A brief introduction to Process synchronization in Operating Systems with classical examples and solutions using semaphores. A good starting tutorial for beginners.
The little Oh (o) notation is a method of expressing the an upper bound on the growth rate of an algorithm’s
running time which may or may not be asymptotically tight therefore little oh(o) is also called a loose upper
bound we use little oh (o) notations to denote upper bound that is asymptotically not tight.
INTRODUCTION
WHAT IS OSI?
OSI MODEL
TYPES OF LAYERS
PHYSICAL LAYER
DATA LINK LAYER
NETWORK LAYER
TRANSPORT LAYER
SESSION LAYER
PRESENTATION LAYER
APPLICATION LAYER
Operating system 24 mutex locks and semaphoresVaibhav Khanna
Mutual Exclusion - If process Pi is executing in its critical section, then no other processes can be executing in their critical sections
2. Progress - If no process is executing in its critical section and there exist some processes that wish to enter their critical section, then the selection of the processes that will enter the critical section next cannot be postponed indefinitely
3. Bounded Waiting - A bound must exist on the number of times that other processes are allowed to enter their critical sections after a process has made a request to enter its critical section and before that request is granted
Assume that each process executes at a nonzero speed
No assumption concerning relative speed of the n processes
Semaphore = a synchronization primitive
higher level of abstraction than locks
invented by Dijkstra in 1968, as part of the THE operating system
A semaphore is:
a variable that is manipulated through two operations, P and V (Dutch for “test” and “increment”)
P(sem) (wait/down)
block until sem > 0, then subtract 1 from sem and proceed
V(sem) (signal/up)
add 1 to sem
Do these operations atomically
Topic: I/O Buffering in Operting System
Discussion Points:
-Why we need buffering?
-Problems in buffering
-Types of I/O Devices
-Types of Buffer
-Types of approaches to buffering
-Which type of buffer is used with which type of I/O device and how?
The little Oh (o) notation is a method of expressing the an upper bound on the growth rate of an algorithm’s
running time which may or may not be asymptotically tight therefore little oh(o) is also called a loose upper
bound we use little oh (o) notations to denote upper bound that is asymptotically not tight.
INTRODUCTION
WHAT IS OSI?
OSI MODEL
TYPES OF LAYERS
PHYSICAL LAYER
DATA LINK LAYER
NETWORK LAYER
TRANSPORT LAYER
SESSION LAYER
PRESENTATION LAYER
APPLICATION LAYER
Operating system 24 mutex locks and semaphoresVaibhav Khanna
Mutual Exclusion - If process Pi is executing in its critical section, then no other processes can be executing in their critical sections
2. Progress - If no process is executing in its critical section and there exist some processes that wish to enter their critical section, then the selection of the processes that will enter the critical section next cannot be postponed indefinitely
3. Bounded Waiting - A bound must exist on the number of times that other processes are allowed to enter their critical sections after a process has made a request to enter its critical section and before that request is granted
Assume that each process executes at a nonzero speed
No assumption concerning relative speed of the n processes
Semaphore = a synchronization primitive
higher level of abstraction than locks
invented by Dijkstra in 1968, as part of the THE operating system
A semaphore is:
a variable that is manipulated through two operations, P and V (Dutch for “test” and “increment”)
P(sem) (wait/down)
block until sem > 0, then subtract 1 from sem and proceed
V(sem) (signal/up)
add 1 to sem
Do these operations atomically
Topic: I/O Buffering in Operting System
Discussion Points:
-Why we need buffering?
-Problems in buffering
-Types of I/O Devices
-Types of Buffer
-Types of approaches to buffering
-Which type of buffer is used with which type of I/O device and how?
Notes: Verilog Part 4- Behavioural ModellingJay Baxi
This is the 4th part of the Verilog HDL notes prepared from Verilog HDL by Samir Palnitkar .
It contains a broad view on behavioural modelling the second most frequently used level of abstraction needed for designing of sequential circuits.
Talon systems - Distributed multi master replication strategySaptarshi Chatterjee
Data Replication is the process of storing data in more than one site or node.It is useful in improving the availability of data. The result is a distributed database in which users can access data relevant to their tasks without interfering with the work of others.Data Replication is generally performed to provide a consistent copy of data across all the database nodes.
Traditionally it’s done by copying data from one database server to another, so that all the servers can have the same data. Our implementation, proposes a completely different approach. Instead of copying data from one node to another, in our design , master replicas do not directly communicate between each other and work virtually independently for write queries. For read queries, an independent process consults all the replicas to constitute a quorum. and returns the result if a majority of the machines in the system response with the same result
MySQL Replication Performance Tuning for Fun and Profit!Vitor Oliveira
MySQL Replication, in addition to bringing high-availability, is the foundation to build high-performance MySQL database systems. Using read scale-out and sharding one can design systems that go from the capacity of a single server to supporting the largest internet sites. But to design and operate high-performance, efficient, manageable and reliable deployments requires knowing the intricacies of the underlying technologies.
This session will provide insights on the main factors that affect the performance of Asynchronous Replication and Group Replication, and how to configure them to make the most out of the underlying computing system. It will also show the latest developments in MySQL 5.7 and 8.0, in areas spanning from group communication to the multi-threaded slave applier, and how effective they are in helping meet the performance requirements in terms of throughput, latency and durability to support the most demanding workload types.
Don't Wait! Develop responsive applications with Java EE7 insteadErin Schnabel
A revision to a previous session: we explore how the async mechanisms in Java EE7 help you be more responsive in the backend. Includes an overview of how EE7 technologies enable RxJava to be used in a container-friendly way.
Working with XSLT, XPath and ECMA Scripts: Make It Simpler with Novell Identi...Novell
Using XPath, XSLT, ECMA scripts judiciously is vital to building complex policies easily in your identity management projects. This session will compare these techniques to achieve similar results and show exact benefits of using one over the other in specific use cases. It will also go through the lifecyle of Novell Identity Manager policy management: how the policies are developed, tested and deployed in Novell Identity Manager Designer. This is an advanced session, and assumes you have a significant level of experience with Identity Manager and Designer.
Understand and Harness the Capabilities of Intel® Xeon Phi™ ProcessorsIntel® Software
The second-generation Intel® Xeon Phi™ processor offers new and enhanced features that provide significant performance gains in modernized code. For this lab, we pair these features with Intel® Software Development Products and methodologies to enable developers to gain insights on application behavior and to find opportunities to optimize parallelism, memory, and vectorization features.
Fine-tuning Group Replication for PerformanceVitor Oliveira
This presentation is an overview of Group Replication from the perspective of performance optimization. It shows the main moving parts, the available options and how they can be used to tune its behaviour, and also a few significant benchmark results.
Final project report on grocery store management system..pdfKamal Acharya
In today’s fast-changing business environment, it’s extremely important to be able to respond to client needs in the most effective and timely manner. If your customers wish to see your business online and have instant access to your products or services.
Online Grocery Store is an e-commerce website, which retails various grocery products. This project allows viewing various products available enables registered users to purchase desired products instantly using Paytm, UPI payment processor (Instant Pay) and also can place order by using Cash on Delivery (Pay Later) option. This project provides an easy access to Administrators and Managers to view orders placed using Pay Later and Instant Pay options.
In order to develop an e-commerce website, a number of Technologies must be studied and understood. These include multi-tiered architecture, server and client-side scripting techniques, implementation technologies, programming language (such as PHP, HTML, CSS, JavaScript) and MySQL relational databases. This is a project with the objective to develop a basic website where a consumer is provided with a shopping cart website and also to know about the technologies used to develop such a website.
This document will discuss each of the underlying technologies to create and implement an e- commerce website.
Hierarchical Digital Twin of a Naval Power SystemKerry Sado
A hierarchical digital twin of a Naval DC power system has been developed and experimentally verified. Similar to other state-of-the-art digital twins, this technology creates a digital replica of the physical system executed in real-time or faster, which can modify hardware controls. However, its advantage stems from distributing computational efforts by utilizing a hierarchical structure composed of lower-level digital twin blocks and a higher-level system digital twin. Each digital twin block is associated with a physical subsystem of the hardware and communicates with a singular system digital twin, which creates a system-level response. By extracting information from each level of the hierarchy, power system controls of the hardware were reconfigured autonomously. This hierarchical digital twin development offers several advantages over other digital twins, particularly in the field of naval power systems. The hierarchical structure allows for greater computational efficiency and scalability while the ability to autonomously reconfigure hardware controls offers increased flexibility and responsiveness. The hierarchical decomposition and models utilized were well aligned with the physical twin, as indicated by the maximum deviations between the developed digital twin hierarchy and the hardware.
Saudi Arabia stands as a titan in the global energy landscape, renowned for its abundant oil and gas resources. It's the largest exporter of petroleum and holds some of the world's most significant reserves. Let's delve into the top 10 oil and gas projects shaping Saudi Arabia's energy future in 2024.
3. DefinitionDefinition
➔
Proposed by Dijkstra in 1965
➔
Used to manage concurrent processes by using
a simple integer value, which is known as a
semaphore.
➔
Semaphore is simply a variable which is non-
negative and shared between threads.
➔
This variable is used to solve the critical section
problem and to achieve process synchronization
in the multiprocessing environment.
4. Operations SupportedOperations Supported
Only Two Atomic operations
➔
P(sem) : Waits for semaphore to become
positive, then decrement it by 1 .
➔
V(sem) : [Signal] Increments semaphore
by 1 and wakes up a waiting thread at P(),
if any.
5. ➔
Atomic means that variable on which read,
modify and update happens at the same
time/moment with no pre-emption i.e. in
between read, modify and update no other
operation is performed that may change
the variable.
6. Types Of SemaphoresTypes Of Semaphores
Binary SemaphoreBinary Semaphore (aka mutex semaphore)(aka mutex semaphore)
➔
Initialized to 1
➔
guarantees mutually exclusive access to resource (e.g., a critical
section of code)
➔
only one thread/process allowed entry at a time
Counting Semaphore
➔
Initialized to N
➔
N = number of units Available
➔
represents resources with many (identical) units available
➔
allows threads to enter as long as more units are available
➔
