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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.


  • 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

Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
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
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
sciencedirect big data base
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
characteristics of micro business
for teaching engĺish at school how nano technology help us
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
what is the actual application of fullerenes nowadays?
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
is Bucky paper clear?
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Do you know which machine is used to that process?
how to fabricate graphene ink ?
for screen printed electrodes ?
What is lattice structure?
s. Reply
of graphene you mean?
or in general
in general
Graphene has a hexagonal structure
On having this app for quite a bit time, Haven't realised there's a chat room in it.
what is biological synthesis of nanoparticles
Sanket Reply
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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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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