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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

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.
yes that's correct
I think
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
How we are making nano material?
what is a peer
What is meant by 'nano scale'?
What is STMs full form?
scanning tunneling microscope
how nano science is used for hydrophobicity
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
what is differents between GO and RGO?
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
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
The nanotechnology is as new science, to scale nanometric
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
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 did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit Reply
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with the given example MOV BX,AX describe the sequence that will be followed using instruction state diagram
Gireesh 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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