The architecture of computer hardware and systems software an information technology approach ch11

Symmetrical Multiprocessing Each CPU has equal access to resources  Each CPU determines what to run using a... Client-Server Architecture File storage, databases, printing services, l

Chapter 11

Modern Computer Systems, Clusters, and Networks

The Architecture of Computer Hardware

and Systems Software:

An Information Technology Approach

3rd Edition, Irv Englander John Wiley and Sons 2003

Basic Personal Computer System

Mainframe Computer System

Major PC System Components

System Performance

Improvements

 Increase the processing power of a system

 Parallel processing

 Tightly coupled systems

 Loosely coupled systems

Tightly Coupled Systems

shared memory, I/O, etc

redundant program execution

 Master-slave multiprocessing

 Symmetrical multiprocessing (SMP)

Tightly Coupled Systems

Master-Slave Multiprocessing

 Master CPU

 Advantages

 Disadvantages

system fails

Symmetrical Multiprocessing

 Each CPU has equal access to resources

 Each CPU determines what to run using a

Loosely Coupled Systems

 Clusters or multi-computer systems

 Each system has its own CPU, memory, and I/

Shared-Disk Model

 Better load balancing

 Complex software required for

transactional processing (lock, commit phases)

Cluster Models

Blade and Rack of Beowulf Cluster

Computer Interconnection

 Communication channel – pathway for data

movement between computers

Example: Point-to-Point

Client-Server Architecture

 File storage, databases, printing services, login services, web services

 Execute programs in its own memory

 Access files either locally or can request

files from a server

Client-Server Network

LAN Topology

shared medium environment

LAN Topologies: Bus

using tap

entire medium (both directions)

prevent the signal from bouncing

Bus LAN Diagram

LAN Topologies: Tree

branches which may have branches of their own

network, can be received by any station

LAN Topologies: Ring

point-to-point links in a ring

receiver checks its address, and copies those intended for it into a local buffer

which removes it from network

usage

Ring LAN Diagram

LAN Topologies: Star

a central station, usually with two

undirectional links

pairs of nodes together

switch frames among stations

network to go down

Star LAN Diagram

Ethernet MAC Protocol

 MAC – Medium Access Control

 Ethernet and CSMA/CD

 Carrier sense multiple access with collision

detection

 Four step procedure

 If medium is idle, transmit

 If medium is busy, listen until idle and then transmit

 If collision is detected, cease transmitting

 After a collision, wait a random amount of time

before retransmitting

Ethernet Frame

Switched Ethernet

Token Ring MAC Protocol

 Token “seized” by changing a bit on the

circulating frame to indicate start of frame rather than token

 Default configuration requires sender to

complete transmission and begin receiving transmitted frame before releasing the

token

 “Early token release” allows release of

token after transmission but before receipt

of frame

layout

repeats the signal on the outgoing line

WANs

 Read all frames from each network

 Accept frames from sender on one network

that are addressed to a receiver on the other network

 Retransmit frames from sender using MAC

protocol for receiver

networks

correspond to the protocol of the other network

to the router

Wide Area Network

 Circuit switching

 Dedicated channel between source and

destination for duration of connection

 Message switching

 Dedicated channel for an entire message

 Packet switching

 An independent path is created for each datagram

 Virtual circuit switching

 A route is created from source to destination

before transmission begins and all datagrams are sent using the same route

cluster administration and

load-balancing software

using the above method

High Performance Computing

 Massively parallel processor architectures

Parallel Computers

 Massively parallel architectures

 Hundreds to millions of CPUs

 CPUs have small amounts of local memory

 All CPUs have access to global shared

memory

 Pipelined CPUs

 Results from one CPU flow to the next CPU for

additional processing