DistOS 2014W Lecture 1: Difference between revisions

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'''What is an OS?''' Here are some ideas of what it could mean:
== What is an Operating System? ==
* a hardware abstraction
* Consistent execution environment. (ie. code written to interface -- think portable code)
* manages I/O
* Resource management/Multiplexing
* Communication infrastructure (example Inter Process Communication mechanisms) between the users (process, applications) of the Operating System.


An OS can be defined by the role it plays in the programming of systems. It takes care of resource management and creates abstraction. An OS turns hardware into the computer/api/interface you WANT to program.
In general, an OS allows you to run the same applications on (slightly) different hardware. Here are a few thoughts on what the responsibilities and functionality are of modern operating systems, and what we expect from something calling itself an OS:
* A hardware abstraction layer such that diverse hardware resources can be accessed uniformly by software
* A consistent execution environment, which hardware doesn't provide (ie. code written to interface &emdash; think portable code)
* Management of I/O (such as user I/O, machine I/O i.e. network I/O, sensors, videos, etc.)
* Resource management through multiplexing and policy use
** Multiplexing (sharing): one resource wanted by multiple users
* Communication infrastructure (for example inter-process communication) between the users (process, applications) of the operating system.
* Management of synchronization and concurrency issues
 
We could also say that an OS turns the computer you have into the computer you want. An OS can be defined by the role it plays in the programming of systems. It takes care of resource management and creates abstraction. An OS turns hardware into the computer/API/interface we '''want''' to program.


This is similar to how the browser is becoming the OS of the web. The browser is
This is similar to how the browser is becoming the OS of the web. The browser is
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etc.), the browser abstracts the device's hardware and OS away.
etc.), the browser abstracts the device's hardware and OS away.


'''So, what's a distributed OS?'''
== What is a distributed OS? ==


Anil prefers to think of this 'logically' than functionally/physically.  This is
Anil prefers to think of this 'logically' rather than functionally/physically.  This is
because the old distributed operating system (DOS) model applies to today's systems
because the old distributed operating system (DOS) model applies to systems today which we
(ie. managing multiple cores, etc). The traditional definition is systems that
don't consider distributed (ie. managing multiple cores, etc). The traditional definition is systems that
manage their resources over a Network.
manage their resources over a Network.


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the way of truth. These concepts to do not fit into well defined classes.
the way of truth. These concepts to do not fit into well defined classes.


'''Anil's definition''': "taking the distributed pieces of a system you have and
To draw parallels to our previous definition of operating systems, a distributed OS takes the distributed pieces of a system, and turn it into the system you want.
turning it into the system you WANT."
 
It is good to think about about DOS's within the context of who/what is in
control, in terms of who makes and enforces decisions in DOS. The traditional kernel-process model is a dictatorship. Authoritarian
model of control. The kernel controls what lives or dies.  The internet, by
contrast, is decentralised (eg. DNS). Distributed systems may have distributed
policies where there is not one source of power.Even in DOS paradigm we can see instances of authoritarian/centralized approaches one example being the walled garden model employed by Apple iOS. Anil's observation is that centralized systems has an inherent fragility built into and these kind of systems comes to existence and disappear after a while. Examples being AOL, Myspace. Even the Facebook also looks to be a possible candidate for a similar fate.
 
 
----
 
 
Yuan Liu's Notes
 
'''(Normal) Operating Systems'''
 
OS allows you to run on (slightly) different hardware. Functionalities and responsibilities of OSes include:
 
* abstracts hardware such that hardware resources can be accessed by software
* provides consistent execution environment (which hardware doesn't provide)
* manages I/O (such as user I/O, machine I/O i.e. network I/O, sensors, videos, etc.)
* manages resources via mulitplexing
* multiplexing (sharing): one resource wanted by multiple users
* O/S turns a computer you want to a computer you want to program
* manages synchronization and concurrency issues
* resource management and abstraction
* uses policies to manage resources
 
'''Distributed O/S'''
* turns a distributed system (with their hardware) into a distributed system you want to program
* resource management: who is in charge?
* in local O/S, the kernel is the boss
* in distributed O/S, the control is decentralized
* different humans control their machine
* has distributed policies for managing resources
* who decides control? different than local O/S


'''Other thoughts'''
It is good to think about about DOSes within the context of who/what is in
* a more centralized system will become fragile later
control, in terms of who makes and enforces decisions in DOSes. In essence, who is in charge? The traditional kernel-process model is a dictatorship, an authoritarian
* concentration of policy tend to fall apart in the future, according to Anil
model of control. The kernel controls what lives or dies.  The internet, in contrast, is decentralised (eg. DNS&emdash;to some extent, ignoring centralized roots). Distributed systems may have distributed
policies where there is not one source of power. Even in DOS we see instances of authoritarian/centralized approaches one example being the walled garden model employed by Apple's iOS. Anil's observation is that centralized systems has an inherent fragility built into and these kind of systems come into existence and disappear after a while. Examples being AOL, Myspace. Even Facebook also looks to be a possible candidate for a similar fate. Also, concentrations on policy will tend to fall apart in the future.

Latest revision as of 17:59, 20 April 2014

What is an Operating System?

In general, an OS allows you to run the same applications on (slightly) different hardware. Here are a few thoughts on what the responsibilities and functionality are of modern operating systems, and what we expect from something calling itself an OS:

  • A hardware abstraction layer such that diverse hardware resources can be accessed uniformly by software
  • A consistent execution environment, which hardware doesn't provide (ie. code written to interface &emdash; think portable code)
  • Management of I/O (such as user I/O, machine I/O i.e. network I/O, sensors, videos, etc.)
  • Resource management through multiplexing and policy use
    • Multiplexing (sharing): one resource wanted by multiple users
  • Communication infrastructure (for example inter-process communication) between the users (process, applications) of the operating system.
  • Management of synchronization and concurrency issues

We could also say that an OS turns the computer you have into the computer you want. An OS can be defined by the role it plays in the programming of systems. It takes care of resource management and creates abstraction. An OS turns hardware into the computer/API/interface we want to program.

This is similar to how the browser is becoming the OS of the web. The browser is the key abstraction needed to run web apps. It is the interface web developers target. It doesn't matter what you consume a given website on (eg. a phone, tablet, etc.), the browser abstracts the device's hardware and OS away.

What is a distributed OS?

Anil prefers to think of this 'logically' rather than functionally/physically. This is because the old distributed operating system (DOS) model applies to systems today which we don't consider distributed (ie. managing multiple cores, etc). The traditional definition is systems that manage their resources over a Network.

A lot of these definitions are hard to peg down because simplicity always gets in the way of truth. These concepts to do not fit into well defined classes.

To draw parallels to our previous definition of operating systems, a distributed OS takes the distributed pieces of a system, and turn it into the system you want.

It is good to think about about DOSes within the context of who/what is in control, in terms of who makes and enforces decisions in DOSes. In essence, who is in charge? The traditional kernel-process model is a dictatorship, an authoritarian model of control. The kernel controls what lives or dies. The internet, in contrast, is decentralised (eg. DNS&emdash;to some extent, ignoring centralized roots). Distributed systems may have distributed policies where there is not one source of power. Even in DOS we see instances of authoritarian/centralized approaches one example being the walled garden model employed by Apple's iOS. Anil's observation is that centralized systems has an inherent fragility built into and these kind of systems come into existence and disappear after a while. Examples being AOL, Myspace. Even Facebook also looks to be a possible candidate for a similar fate. Also, concentrations on policy will tend to fall apart in the future.