Computer System and Architecture

8/7/2019 Computer System and Architecture

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COMPUTER SYSTEM AND

ARCHITECTURE

(MODULE CODE- AICT001-3-2)

CPU, MEMORY AND ADVANCED ARCHITECTURE


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Introduction

The report emphasizes on two things-

General Architecturei.e. CPU and Memory

Advanced architecture why it is developed, how it

works, how it differs from the Von Neumann

architecture, which CPU vendor uses it etc.


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Microprocessors

Microprocessors has input, output and process.

Input and Output are a series of voltage used tocontrol external devices.

Different Trends include-

Increasing number of Cores

Awareness and improvements in energy efficiency

Include High Speed Cache and Buses Reducing the size of the Processor

Continuing advances in virtualization


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CPU and Memory

For Better performance, Faster Program Execution,

maximum throughput compatibility is required.


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Cache

Cache Coherence each CPU is having its own

copy of data in its cache

Bus Snooping

Directory Based approach

Onboard Cache on the motherboard or off chip

Write Back Cache- two approaches to write data

back in main memory. Implementation Direct Mapped Cache, Associate

Mapping, Set Associative Mapping


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Virtual Memory

Illusion of Memory

Implemented using two schemes-

Demand Paging valid-invalid bit method, 1 for page

present and o for absent (page fault). The they are

loaded into frames.

Demand Segmentation- each row of lookup table has a

starting address of the logical memory, size of the

block and starting address for physical memory

However both operates the same.


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Demand Paging


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Problem of Fragmentation

Fixed Memory Partitioning

Variable Memory Partitioning

Both leads to creation of small holes when theprocesses are swapped in.


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Memory Hierarchy


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Role of Registers

Registers are defined to perform specific purposessuch as MAR, MDR, Accumulator etc.

Used as calculator to perform arithmetic calculations

such as Accumulator and are used to hold addressof instructions such as Address Registers.

Special purpose register are used to store the statusof the program. It consist of program counter, stack

pointer and status registers. It has a higher transfer rate and the minimum access

time as it is directly attached to the CPU.


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Addressing Modes

Simplifies the memory references, adds convenience

and flexibility to have modes of addressing, and it

allows a large range of addressable memory while

using a reasonable number of bits.

Help writing programs that uses loops and all.

For Example- Indexed Addressing. Now a days

computer allows programmer accessible registersthat manipulate data directly between registers.


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Numerical


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ADVANCED ARCHITECTURE

COMPUTER SYSTEM AND ARCHITECTURE


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Multicore

Doing several operations at a single time increases

efficiency.

Processor reads and executes fixed and variable

length instructions.

Reason for Development-

Increasing CPU performance

Applications demanded thread level parallelism Increased available space.


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How it Works

Concept of multi-threaded programs or software.

Multithreaded software

Operating systems that have the ability to split

tasks and commands into a set of separate

workloads that could then be processed and run

simultaneously on each of the cores present.

Vendors Intel and AMD AMD Phenom II X2, Intel Core Duo, and

AMD Phenom II X 6, Intel Core i7 Extreme Edition 980

X etc.


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Different from Von Neumann

Architecture

The Von Neumann architecture is concerned with the

sequential processing of instructions whereas in

multicore several instructions can be processed

concurrently.

Consist of one CPU but multicore consist of more

than one CPU.


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Success/Failure

Success-

Low Heat Dispatch

Thread level parallelism

Failure

Applications are not capable of splitting tasks

Documents

Computer System and Architecture