Distributed OS Overview - Revision history

Soma: Reverted edits by Katrinewhite79 (Talk) to last revision by Bishopdesmond33

2010-08-14T01:54:00Z

Reverted edits by Katrinewhite79 (Talk) to last revision by Bishopdesmond33

← Older revision		Revision as of 01:54, 14 August 2010
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	* Dynamic reconfiguration		* Dynamic reconfiguration
	* Exploit local resources.		* Exploit local resources.
	*[http://customresearchpapers.co.uk/paper-writing-service paper writing service]

Katrinewhite79: /* What Makes a Good Distributed Operating System? */

2010-04-09T21:04:57Z

What Makes a Good Distributed Operating System?

← Older revision		Revision as of 21:04, 9 April 2010
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	* Dynamic reconfiguration		* Dynamic reconfiguration
	* Exploit local resources.		* Exploit local resources.
			*[http://customresearchpapers.co.uk/paper-writing-service paper writing service]

Bishopdesmond33: minor typos

2008-01-15T01:49:15Z

minor typos

← Older revision		Revision as of 01:49, 15 January 2008
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	<p>'''Process Layer'''<br />		<p>'''Process Layer'''<br />
	At the process layer, we can perform the distribution over the network using TCP/IP. Unfortunately, TCP/IP has a high latency. We can use ethernet to reduce the latency, but it is only a viable solution for LAN based systems. ~~Therefor~~, latency will always be present.</p>		At the process layer, we can perform the distribution over the network using TCP/IP. Unfortunately, TCP/IP has a high latency. We can use ethernet to reduce the latency, but it is only a viable solution for LAN based systems. Therefore, latency will always be present.</p>
	We can deal with latency by caching a local copy of data which effectively reduces the amount of communication required. The downside is, caching introduces a need for synchronization.		We can deal with latency by caching a local copy of data which effectively reduces the amount of communication required. The downside is, caching introduces a need for synchronization.

Bishopdesmond33: minor typos

2008-01-15T01:48:52Z

minor typos

← Older revision		Revision as of 01:48, 15 January 2008
Line 13:		Line 13:
	<p>'''Process Layer'''<br />		<p>'''Process Layer'''<br />
	At the process layer, we can perform the distribution over the network using TCP/IP. Unfortunately, TCP/IP has a high latency. We can use ethernet to reduce the latency, but it is only a viable solution for LAN based systems. Therefor, latency will always be present.</p>		At the process layer, we can perform the distribution over the network using TCP/IP. Unfortunately, TCP/IP has a high latency. We can use ethernet to reduce the latency, but it is only a viable solution for LAN based systems. Therefor, latency will always be present.</p>
	~~<p>~~We can deal with latency by caching a local copy of data which effectively reduces the amount of communication required. The downside is, caching introduces a need for synchronization.		We can deal with latency by caching a local copy of data which effectively reduces the amount of communication required. The downside is, caching introduces a need for synchronization.

	<p>We can also deal with latency by compressing the data and splitting up the computation "wisely". Computers are not wise enough to do it effectively, leaving it up to the programmers. Programmers split up such computations by introducing client/server architectures, using web applications and web services as well as using distributes file systems. For example, spam uses internet resources to communicate by email with large numbers of users. Spam is a feature of the Internet, everyone should be able to send an email to everyone and spam uses that resource. Distributed operating systems on the scale of the Internet capable of wise resource management do not yet exist. </p>		<p>We can also deal with latency by compressing the data and splitting up the computation "wisely". Computers are not wise enough to do it effectively, leaving it up to the programmers. Programmers split up such computations by introducing client/server architectures, using web applications and web services as well as using distributes file systems. For example, spam uses internet resources to communicate by email with large numbers of users. Spam is a feature of the Internet, everyone should be able to send an email to everyone and spam uses that resource. Distributed operating systems on the scale of the Internet capable of wise resource management do not yet exist. </p>

Taisia at 21:07, 13 January 2008

2008-01-13T21:07:02Z

New page

== Distributed Operating Systems ==

[[Image:OS4000_Distributed.png|A distributed operating system.]]

At what level do you want to start the distribution?
'''Hardware Layer''' 
If memory is shared, communication is trivial ie. parallel computers (multi core).

'''Kernel Layer''' 
Distributing at the kernel layer will avoid API and User Space changes. So why don't we share at the lower kernel layer? The main reason is security and performance. We can assume that memory is fast (low latency) so we need to share memory across each computer in the distribution. To share memory in such a way presents a challenge. So why isn't virtual memory enough? Typically because of contention over memory. Virtual memory is slow; duplicating memory pages and synchronizing them across the network takes too much time.

'''Process Layer''' 
At the process layer, we can perform the distribution over the network using TCP/IP. Unfortunately, TCP/IP has a high latency. We can use ethernet to reduce the latency, but it is only a viable solution for LAN based systems. Therefor, latency will always be present.
We can deal with latency by caching a local copy of data which effectively reduces the amount of communication required. The downside is, caching introduces a need for synchronization.

We can also deal with latency by compressing the data and splitting up the computation "wisely". Computers are not wise enough to do it effectively, leaving it up to the programmers. Programmers split up such computations by introducing client/server architectures, using web applications and web services as well as using distributes file systems. For example, spam uses internet resources to communicate by email with large numbers of users. Spam is a feature of the Internet, everyone should be able to send an email to everyone and spam uses that resource. Distributed operating systems on the scale of the Internet capable of wise resource management do not yet exist. 
 
== What Makes a Good Distributed Operating System? ==

A good distributed OS must be:
* Reliable and support dynamically scalable storage.
* More processing power (CPU - linear scaling).
* Manageable (it should be easy to manage, like a single computer)
* Easy to write programs
* Support fore single sign on!!
* A single system image
* Reliability (fault tolerant to software and hardware errors)
* Dynamic reconfiguration
* Exploit local resources.