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Introduction to Operating Systems

Operating system is a hard term to define. Silberschatz e.t. defines that “ an operating system is a program that manages the computer hardware. ” However, what you consider an operating system depends on your needs and your view of the system. The first view is that operating system is a scheduler/simulator, on this view, the operating system has resources for which it is in charge, responsible for handing them out as well as recovering them later. Resources here include CPU, memory, I/O devices, and disk space. The second view is that operating system is a virtual machine, it means operating system provides a new machine. This machine could be the same as the underlying machine. Allows many users to believe they have an entire piece of hardware to themselves. This could implement a different, perhaps more powerful machine. Or just a different machine entirely. It may be useful to be able to completely simulate another machine with your current hardware. The other view is that operating system is a multiplexor which allows sharing of resources, provides protection from interference, and provides for a level of cooperation between users. This also for the economic reasons, we can’t afford for all resources.

According to these three views, if we have enough hardware to give anyone too much; the hardware was well defined; the sharing problem is solved then we would not need operating systems. Unfortunatly, they will still be needed as a servant or provider of services: need to provide things like in the above views, but deal with environments that are less than perfect, need to help the users use the computer by: providing commonly used subroutines; providing access to hardware facilities; providing higher-level "abstract" facilities; providing an environment which is easy, pleasant, and productive to use. This view as a provider of services fits well with our modern network view of computing, where most resources are services.

Internally, operating systems vary greatly in their makeup, since they are organized along many different lines. The design of a new operating system is a major task. It is important that the goals of the system be well defined before the design begins. These goals form the basis for choices among various algorithms and strategies.

Because an operating system is large and complex, it must be created piece by piece. Each of these pieces should be well delineated portion of the system, with carefully defined inputs, outputs, and functions.

What are the desires of an operating system?

We can discuss them in term of: Usability, Facilities, Cost, and Adaptability.

Usability:

  • Robustness

OS accept all valid inputs withour error, and gracefully handle all invalid inputs. OS would not be crashed in any circumtances, and could be recovered in the case that we suddenly remove hardware while they are running, or lost of power supplied.

  • Consistency

For example, if "-" means options flags in one place, it means it in another. The key idea is conventions . We should base on the concept: The Principle of Least Astonishment. This helps us easy to understand and adapt with the new system.

Questions & Answers

where we get a research paper on Nano chemistry....?
Maira Reply
what are the products of Nano chemistry?
Maira Reply
There are lots of products of nano chemistry... Like nano coatings.....carbon fiber.. And lots of others..
learn
Even nanotechnology is pretty much all about chemistry... Its the chemistry on quantum or atomic level
learn
Google
da
no nanotechnology is also a part of physics and maths it requires angle formulas and some pressure regarding concepts
Bhagvanji
Preparation and Applications of Nanomaterial for Drug Delivery
Hafiz Reply
revolt
da
Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
Nasa has use it in the 60's, copper as water purification in the moon travel.
Alexandre
nanocopper obvius
Alexandre
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
Any one who tell me about Preparation and application of Nanomaterial for drug Delivery
Hafiz
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
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Source:  OpenStax, Operating systems. OpenStax CNX. Aug 13, 2009 Download for free at http://cnx.org/content/col10785/1.2
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