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1. introduction

In the previous sections of this course. we have concentrated on singleprocessor architectures and techniques to improve upon their performance, such as:

– Efficient algebraic hardware implementations

– Enhanced processor operation through pipelined instruction execution and multiplicity of functional units

– Memory hierarchy

– Control unit design

– I/O operations

Through these techniques and implementation improvements, the processing power of a computer system has increased by an order of magnitude every 5 years. We are (still) approaching performance bounds due to physical limitations of the hardware.

  • Several approaches of parallel computer are possible

– Improve the basic performance of a single processor machine

Architecture / organization improvements

Implementation improvements


Clock speed


– Multiple processor system architectures

Tightly coupled system

Loosely coupled system

Distributed computing system

- Parallel computer: SIMD computer, MIMD computer

2. multiple processor systems

System with multiprocessor CPUs can be divided into multiprocessor and multicomputers. In this section we will first study multiprocessors and then multicomputers

Shared-memory multiprocessor

A parallel computer in which all the CPUs share a common memory is called a tightly coupled systems

Figure 16.1. Tightly coupled systems, Shased-memory multiprocessor

  • The features of the system are as follow.

– Multiple processors

– Shared, common memory system

– Processors under the integrated control of a common operating system

– Data is exchanged between processors by accessing common shared variable locations in memory

– Common shared memory ultimates presents an overall system bottleneck that effectively limits the sizes of these systems to a fairly small number of processors (dozens)

Message-passing multiprocessor

A parallel computer in which all the CPUs has a local independent memory is called a loosely coupled systems

Figure 16.2. Loosely coupled systems, Message-passing multiprocessor

  • The features of the system are as follow.

– Multiple processors

– Each processor has its own independent memory system

– Processors under the integrated control of a common operating system

– Data exchanged between processors via interprocessor messages

– This definition does not agree with the one given in the text

Distributed computing systems

Now we can see the message-passing computer that multicomputer are held togerther by network.

– Collections of relatively autonomous computers, each capable of independent operation

– Example systems are local area networks of computer workstations

+ Each machine is running its own “copy” of the operating system

+ Some tasks are done on different machines (e.g., mail handler is on one machine)

+ Supports multiple independent users

+ Load balancing between machines can cause a user’s job on one machine to be shifted to another

Performance bounds of multiple processor systems

  • For a system with n processors, we would like a net processing speedup (meaning lower overall execution time) of nearly n times when compared to the performance of a similar uniprocessor system
  • A number of poor performance “upper bounds” have been proposed over the years

Questions & Answers

how do they get the third part x = (32)5/4
kinnecy Reply
can someone help me with some logarithmic and exponential equations.
Jeffrey Reply
sure. what is your question?
okay, so you have 6 raised to the power of 2. what is that part of your answer
I don't understand what the A with approx sign and the boxed x mean
it think it's written 20/(X-6)^2 so it's 20 divided by X-6 squared
I'm not sure why it wrote it the other way
I got X =-6
ok. so take the square root of both sides, now you have plus or minus the square root of 20= x-6
oops. ignore that.
so you not have an equal sign anywhere in the original equation?
Commplementary angles
Idrissa Reply
im all ears I need to learn
right! what he said ⤴⤴⤴
what is a good calculator for all algebra; would a Casio fx 260 work with all algebra equations? please name the cheapest, thanks.
Kevin Reply
a perfect square v²+2v+_
Dearan Reply
kkk nice
Abdirahman Reply
algebra 2 Inequalities:If equation 2 = 0 it is an open set?
Kim Reply
or infinite solutions?
The answer is neither. The function, 2 = 0 cannot exist. Hence, the function is undefined.
Embra Reply
if |A| not equal to 0 and order of A is n prove that adj (adj A = |A|
Nancy Reply
rolling four fair dice and getting an even number an all four dice
ramon Reply
Kristine 2*2*2=8
Bridget Reply
Differences Between Laspeyres and Paasche Indices
Emedobi Reply
No. 7x -4y is simplified from 4x + (3y + 3x) -7y
Mary Reply
is it 3×y ?
Joan Reply
J, combine like terms 7x-4y
Bridget Reply
how do you translate this in Algebraic Expressions
linda Reply
Need to simplify the expresin. 3/7 (x+y)-1/7 (x-1)=
Crystal Reply
. After 3 months on a diet, Lisa had lost 12% of her original weight. She lost 21 pounds. What was Lisa's original weight?
Chris Reply
what's the easiest and fastest way to the synthesize AgNP?
Damian Reply
types of nano material
abeetha Reply
I start with an easy one. carbon nanotubes woven into a long filament like a string
many many of nanotubes
what is the k.e before it land
what is the function of carbon nanotubes?
I'm interested in nanotube
what is nanomaterials​ and their applications of sensors.
Ramkumar Reply
what is nano technology
Sravani Reply
what is system testing?
preparation of nanomaterial
Victor Reply
Yes, Nanotechnology has a very fast field of applications and their is always something new to do with it...
Himanshu Reply
good afternoon madam
what is system testing
what is the application of nanotechnology?
In this morden time nanotechnology used in many field . 1-Electronics-manufacturad IC ,RAM,MRAM,solar panel etc 2-Helth and Medical-Nanomedicine,Drug Dilivery for cancer treatment etc 3- Atomobile -MEMS, Coating on car etc. and may other field for details you can check at Google
anybody can imagine what will be happen after 100 years from now in nano tech world
after 100 year this will be not nanotechnology maybe this technology name will be change . maybe aftet 100 year . we work on electron lable practically about its properties and behaviour by the different instruments
name doesn't matter , whatever it will be change... I'm taking about effect on circumstances of the microscopic world
how hard could it be to apply nanotechnology against viral infections such HIV or Ebola?
silver nanoparticles could handle the job?
not now but maybe in future only AgNP maybe any other nanomaterials
I'm interested in Nanotube
this technology will not going on for the long time , so I'm thinking about femtotechnology 10^-15
can nanotechnology change the direction of the face of the world
Prasenjit Reply
At high concentrations (>0.01 M), the relation between absorptivity coefficient and absorbance is no longer linear. This is due to the electrostatic interactions between the quantum dots in close proximity. If the concentration of the solution is high, another effect that is seen is the scattering of light from the large number of quantum dots. This assumption only works at low concentrations of the analyte. Presence of stray light.
Ali Reply
the Beer law works very well for dilute solutions but fails for very high concentrations. why?
bamidele 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, Computer architecture. OpenStax CNX. Jul 29, 2009 Download for free at http://cnx.org/content/col10761/1.1
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