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Operation on a Process

  1. Process creation:  A user requests, and already running process can creates new processes. Parent process creates children processes using a system call, which, in turn create other processes, forming a tree of processes.
  2. Process pre-empting:  A process pre-empted if I/O event or timeout occurs. Then process moves from running state to ready state and CPU loads another process from ready state to running state, if available.
  3. Process blocking: When a process needs I/O event
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software engineering

What is software? Computer programs and associated documentation. Software products may be developed for a particular customer or may be developed for a general market.

 What are the attributes of good software? Good software should deliver the required functionality and performance to the user and should be maintainable, dependable, and usable. 

What is software engineering?Software engineering is an engineering discipline that is concerned with all aspects of software production from the early
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Geography of Britain: Bristish isles: group of about 5000 islands off the northwest cost of mainland Europe. The highest island is Great Britain which consists of England, Wales and Scotland. The next island is Ireland, which is made up of northern Island (Ulster) and the Irish Republic (Eire). Great Britain and Northern Ireland form the United Kingdom.

The United Kingdom: Great Britain is a geographical expression, the United Kingdom is a political expression. The British Isles today are shared

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Are you ever unhappy with the way the world is going? Many people complain but do not do anything to change it. In Spain and in many other countries, women get less money than men doing the same job. In my opinion everybody should have the same rights./Since the begining of time, women have been treated as inferior human beings. In the early years they were considered as mere objects, whose only utility was to raise the children and to do all the house keeping, while the man was working, or having

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Energy flow in ecosystem-Energy flow (also called Calorific flow)refers to the flow of energy in ecosystem through food chain.


Ecosystems maintain themselves by cycling energy and nutrients obtained from external sources. At the first trophic levelprimary producers (plants, algae, and some bacteria) use solar energy to produce organic plant material through photosynthesis. Herbivores—animals that feed solely on plants—make up the second trophic level. Predators that eat herbivores comprise

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Transport services and protocols: provide communication between app processes running on different hosts. Send side: breaks app messages into segments, passes to network layer. RCV side: reassembles segments into messages, passes to app layer. Network layer: logical communication between host. Transport layer: local communication between processes -relies on enhances, network layer services. TCP: congestion control, flow control, connection setup.Multiplexing(sender): handle data from multiple Read More