Operating system concept P1 week1

Summary

This script delves into the role of operating systems as intermediaries between users and computer hardware, facilitating efficient program execution. It covers the evolution of computing, from military and governmental uses to multifunction mainframes, and the impact of Moore's Law on computer capabilities. The script discusses various storage structures, including volatile and nonvolatile memory, and the significance of interrupts for device communication. It also explores multiprocessor systems, highlighting symmetric multiprocessing, multicore processors, and nonuniform memory access. The advantages of blade servers and cluster systems for high availability and performance are also examined, emphasizing the importance of efficient resource management in modern computing environments.

Takeaways

• 💻 The operating system serves as an intermediary between the user and computer hardware, providing a convenient and efficient environment for executing programs.
• 🔧 Operating systems are complex and manage resources, defining outputs, inputs, and functions, and are used across various devices from IoT to cloud computing.
• 🖥️ A computer system can be divided into four parts: hardware, operating system, application programs, and users, with the operating system controlling the hardware and coordinating its use among applications.
• 🛠️ The operating system is akin to a government, providing an environment for programs to perform useful work, and includes the kernel and system programs.
• 🔄 Interrupts are signals used by hardware to get the CPU's attention, and are managed by the computer using interrupt service routines (ISR).
• 💾 Storage structures are crucial for loading instructions into the CPU, with main memory (RAM) being volatile and requiring non-volatile storage for long-term data retention.
• 🚀 Multiprocessor systems, including multicore processors, are prevalent in modern computing, offering increased throughput and efficiency.
• 🌐 Non-Uniform Memory Access (NUMA) systems allow CPUs to access local memory quickly without contention, but accessing remote memory can introduce performance penalties.
• 🔀 Clustered systems gather multiple CPUs or nodes to provide high availability and high-performance computing, with each node potentially running its own operating system.
• 🔄 High availability in clusters is achieved through redundancy, allowing service to continue even if one or more systems fail, with the ability to gracefully degrade service in the face of hardware failures.

Q & A

What is the primary function of an operating system?

The primary function of an operating system is to act as an intermediary between the user and the computer hardware, providing an environment in which users can execute programs in a convenient and efficient manner.

How does the operating system control the hardware?

The operating system controls the hardware by coordinating its use among various application programs and users, ensuring that resources are properly allocated and managed.

What are the different types of devices that operating systems can be found on?

Operating systems can be found on a variety of devices including mainframe computers, personal computers, enterprise computers, cloud computing environments, smartphones, and Internet of Things devices.

What is the role of the operating system in the context of a computer system?

In the context of a computer system, the operating system acts as a manager that controls the hardware and coordinates its use among various application programs and users, ensuring proper utilization of resources.

What is the significance of Moore's Law in the evolution of computer systems?

Moore's Law predicts that the number of transistors in an integrated circuit will double approximately every 18 months, which has held true and led to computers gaining in functionality while shrinking in size, leading to a variety of uses and types of operating systems.

How do interrupts function within the operating system?

Interrupts function as signals that tell the computer's main processor to stop what it is doing and pay attention to something else, such as a device that needs to communicate with the CPU.

What is the purpose of an Interrupt Service Routine (ISR)?

The purpose of an Interrupt Service Routine (ISR) is to handle the task associated with an interrupt and ensure that everything returns to normal afterward, similar to directing traffic and then ensuring it flows smoothly again.

Why is direct memory access (DMA) important in computer systems?

Direct memory access (DMA) is important because it allows device controllers to transfer a whole block of data directly between the device and main memory without involving the CPU, making data transfer more efficient, especially for slow devices.

What are the advantages of multiprocessor systems?

The advantages of multiprocessor systems include increased throughput, as they can accomplish more work in less time by sharing resources among multiple processors or cores.

What is the difference between symmetric multiprocessing (SMP) and non-uniform memory access (NUMA)?

Symmetric multiprocessing (SMP) involves multiple processors sharing a single memory space, whereas non-uniform memory access (NUMA) provides each CPU with its own local memory, which can be accessed more quickly without contention over the system interconnect.

How do clustered systems enhance the performance and reliability of computing?

Clustered systems enhance performance and reliability by distributing the workload across multiple interconnected computers, allowing for high availability and the continuation of services even if one or more systems in the cluster fail.

Outlines

00:00

💻 Introduction to Operating Systems

The paragraph introduces the concept of an operating system as an intermediary between the user and computer hardware. It emphasizes the role of the operating system in providing a user-friendly environment for executing programs efficiently. The operating system is described as a complex system that manages inputs, outputs, and functions, and is essential for various devices, including IoT devices, smartphones, personal computers, and enterprise systems. The paragraph also discusses the evolution of computing and the importance of the operating system in managing hardware and coordinating the use of resources among different applications.

05:01

🛠️ Understanding Interrupts and Device Management

This paragraph delves into the intricacies of interrupts in computing. It explains how device drivers communicate with hardware and how interrupts signal the CPU to pause its current task to handle a new task. The analogy of a popup grabbing attention is used to describe how interrupts work. The paragraph further discusses how interrupts are managed using a table of interrupt service routines (ISRs), which handle specific interrupts and ensure system continuity. Advanced interrupt handling features are also mentioned, including prioritization and efficient dispatching, which are crucial for system performance, especially in time-sensitive processes.

10:01

💾 Memory and Storage Structures in Computing

The paragraph discusses various memory and storage structures used in computers. It explains the necessity of loading programs into memory, specifically main memory or RAM, to run them. The paragraph also touches on the use of different memory types, such as volatile and non-volatile memory, and the trade-offs between speed, capacity, and volatility. It describes the hierarchy of memory, with faster memory being closer to the CPU and slower memory further away. The concept of direct memory access (DMA) is introduced as a method for efficient data transfer between devices and memory without CPU intervention. The paragraph also mentions the evolution of storage technologies and the role of buses and switches in data communication within a computer system.

15:02

🔄 Multiprocessor and Multicore Systems

This paragraph explores the advantages of multiprocessor and multicore systems, which aim to increase computational power and efficiency. It discusses symmetric multiprocessing (SMP) and its challenges, such as efficient processor utilization and shared data structures. The paragraph also covers the evolution of multiprocessor systems to multicore systems, where multiple computing cores exist on a single chip. The benefits of such systems, including faster on-chip communication and lower power consumption, are highlighted. Additionally, the paragraph touches on non-uniform memory access (NUMA) systems and their ability to scale effectively, although they may face performance penalties when accessing remote memory.

20:03

🌐 Clustered Systems and High Availability

The paragraph introduces clustered systems, which consist of multiple individual computers working together to provide high availability and performance. It differentiates between multiprocessor and clustered systems, with the latter being loosely coupled and often connected via networks. The paragraph discusses the use of clustering for high availability, where the system continues to operate even if one or more nodes fail. It also mentions the concept of graceful degradation and fault tolerance in clustered systems. The importance of parallelization in cluster computing is highlighted, along with the need for special software and applications designed to run in parallel. The paragraph concludes by discussing the role of storage area networks (SANs) in enhancing cluster performance and reliability.

25:04

🔒 Access Control and Cluster Technology

This paragraph focuses on the importance of access control and locking in clustered systems to ensure data integrity and prevent conflicting operations. It discusses the role of distributed lock managers in managing access to shared data. The paragraph also highlights the rapid evolution of cluster technology, with some systems supporting thousands of nodes. The benefits of storage area networks in attaching multiple hosts to shared storage are mentioned, along with the performance and reliability improvements they bring. The paragraph concludes by emphasizing the ongoing advancements in cluster technology and their impact on computing landscapes.

Keywords

💡Operating System

An operating system (OS) serves as an intermediary between the user and the computer hardware, managing computer hardware, software resources, and providing services for computer programs. In the script, the operating system is described as a complex system that allows users to execute programs in a convenient and efficient manner. It is essential for the functioning of any computer system, from personal computers to large enterprise systems and cloud computing environments.

💡Hardware

Hardware refers to the physical components of a computer system, including the central processing unit (CPU), memory, and input/output devices. The script mentions that hardware provides the basic computing resources for the system. It is the tangible part of the computer system that the operating system interacts with to execute tasks and run applications.

💡Software

Software encompasses the non-physical components of a computer system, such as programs, protocols, and routines that instruct the hardware how to perform tasks. The script discusses software in the context of application programs like word processors and web browsers, which define the ways in which hardware resources are used to solve user problems.

💡Interrupt

An interrupt is a signal sent to the CPU by a device or the computer's hardware indicating that it needs attention. In the script, interrupts are likened to popups on a computer that grab the user's attention. They are crucial for handling synchronous events in a computer system, allowing devices to communicate with the CPU without the need for constant polling.

💡Device Driver

A device driver is a software component that allows the operating system to interact with hardware devices. The script explains that when a program wants to perform an operation like reading from a keyboard or writing to a file, it communicates with a device driver, which in turn communicates with the device controller to manage the actual hardware.

💡Multiprocessor System

A multiprocessor system is a computer system that contains two or more processors (CPUs). The script discusses how multiprocessor systems are prevalent across various devices and are designed to increase throughput by allowing more work to be accomplished in less time. They can be found in mobile devices, servers, and high-performance computing systems.

💡Multicore Processor

A multicore processor is a single CPU that contains multiple independent processing units, or cores. The script explains that multicore processors can be more efficient than multiple single-core chips due to faster on-chip communication and lower power consumption. They are common in modern devices, from mobile phones to laptops and servers.

💡Non-Uniform Memory Access (NUMA)

NUMA is a memory architecture used in multiprocessor systems where each CPU has its own local memory and all CPUs share a global memory space. The script mentions that NUMA systems can scale more effectively as more processors are added, but they may introduce latency when a CPU needs to access memory that is local to another CPU.

💡Clustered System

A clustered system is a group of computers connected over a network that work together to provide high availability and high-performance computing. The script describes two types of clustering: symmetric, where one machine is in standby mode while another runs the application, and asymmetric, where multiple hosts run applications and monitor each other.

💡Storage Structure

Storage structure refers to the organization and management of data storage within a computer system. The script discusses various forms of memory, including volatile and non-volatile storage, and the trade-offs between size, speed, and access time. It also touches on the use of semiconductor memory and non-volatile memory devices like flash memory for different storage needs.

💡Direct Memory Access (DMA)

DMA is a feature of computer systems that allows certain hardware subsystems to access main system memory, independent of the CPU. The script explains that DMA is used for efficient transfer of large amounts of data, such as moving data from non-volatile storage to main memory, without burdening the CPU with each individual data transfer.

Highlights

Operating systems act as intermediaries between users and computer hardware.

The purpose of an operating system is to provide a user-friendly environment for executing programs.

Operating systems are large and complex, managing system resources with defined inputs, outputs, and functions.

They are used in a variety of devices, including IoT devices, smartphones, PCs, enterprise computers, and cloud computing environments.

A computer system can be divided into four parts: hardware, operating system, application programs, and users.

Hardware provides the basic computing resources, while application programs define how these resources are used to solve problems.

Operating systems control hardware and coordinate its use among various application programs and users.

The operating system is compared to a government, providing an environment for programs to perform useful work.

The user view of a computer system is through interfaces like monitors, keyboards, and mice.

Early computers were used for military and governmental purposes, such as code breaking and trajectory plotting.

Moore's Law predicts the doubling of integrated circuit capacity every 18 months, which has held true.

There is no universally accepted definition of what constitutes an operating system; it varies greatly across systems.

Interrupts are signals that tell the CPU to stop its current task and attend to something else.

Interrupt service routines (ISR) manage the tasks associated with interrupts and ensure normal system operation afterward.

Advanced operating systems require more sophisticated interrupt handling features.

The CPU uses an interrupt request line to check for device signals after each instruction.

Multiprocessor systems are prevalent in today's computing landscape, from mobile gadgets to servers.

Multicore processors can be more efficient than multiple single-core chips due to faster on-chip communication.

Nonuniform memory access (NUMA) systems allow CPUs to access local memory quickly without contention.

Blade servers are a type of system where multiple processor boards are placed in the same chassis.

Clustered systems gather multiple CPUs together, providing high availability and high-performance computing.

Storage structures are organized into a hierarchy based on capacity and access time, with trade-offs between size and speed.

Direct memory access (DMA) allows device controllers to transfer data directly between devices and main memory, bypassing the CPU.

Transcripts

hello everyone so start a course

operating system

concept so uh an operating system access

intermediary between user and computer

hardware so as you know the propose of

operating system is provide environment

which user can execute programs in

convenient efficient manner so

operating system is large and complex

system H pie should well delayed portion

of system with carefully Define outputs

inputs and

functions operating system are overwar

from cards and some application and some

Internet of Things devices smart phones

yeah personal

computers some Enterprise computers

cloud computing

environment so let's move to the so

overall computer system uh computer uh

can divide roll into four parts which is

Hardware operating system application

program and user Hardware can Central uh

Processing Unit uh the memory and the

input output device provides a basic

Computing resource for the system the

application program such as word

processor spreadsheets capillar and web

browser defines the ways to which these

resource are used to solve user computer

problems the operating system controls

the hardware and coordinates it use

among the various application programs

for the various user so we can also view

computer system and consist of Hardware

software and data so the operating

system provides means for proper use of

this resource and the operating um

operation of computer system and

operating system is similar to a

government like government is Bor from

useful function it's by itself it simply

provides environment with which programs

can do useful work don't understand more

fully the operating system role we

explore some

more viewpoints that user of the of the

system so user view the user view of the

computer R is according interface being

used many computer users SE with laptop

a front of PC consist of monitor

keyboard and mouse so this such system

is designed one user to monopolize its

resource the goal of maximizing

the work that user is performing in this

case the operating system is designed

mostly is of use with some attention

paid for to Performance and security and

non paid to resource

utilization uh how various Hardware

software sources are shared so Computing

started as an experiment to determine

what could be done and quickly move to

fix propose system for military use

before such as code breaking and

trajectory plotting and governmental use

such as sensus calculations those early

computer involved into General propose

multifunction main frames and that's

when pring system were burn so in 1960

Mo La predicts that the number

transition integrate circuit would

double every 18 months and prediction

has held true so computer gain in

function

shrunken sze leading W number of uses

was number of variety operating system

additional we have no Universal accepted

definition of what is part of the

operating

system and simply Viewpoint is that this

includes everything eventor ships when

you order the operating system the

features include however VAR greatly

across system some system take up less

than a megabyte of space Cas and lack

even full screen editor where is other

required Gaby of space and Bas entirely

a graphical window system a more common

definition and one of the we we usually

follow that operating system is one of

program running all times on the

computer usually call it the kernel

along with kernel there are two other

type of program system programs which

are assed with operating system but not

necessarily part of the kernel and

applications uh programs which include

all programs not associated with

operation of the

system so

interrupts um a computer when program

wants to do something like read from the

keyboard write a file it talks to device

driver

yeah so this driver communication with

Device control which manage the actual

Hardware like keboard or storage

device when device controller finish it

task uh it needs to tell device drivers

that is done this communication is done

using something called an interrupt an

interrupt is like a signal that tells

the computer main process to stop what

is doing and pay attention to something

else imagine you're working on a

computer and suddenly popup appears that

popups like interrupt it grabs your

attention and ask you to do something

else so in the computer case it's a

interrupt asking CPU to do something

specific to manage this interrupts

efficiently the computer use a table

that contains pointers to different

roads to know how to handle speciic

interrupts so these roots are called

interrupt service

routines uh when interrupts happens the

CPU looks in the table find the right

ACR and follows its

instructions the ACR not only completes

the task of SE with interrupt but also

make sure that everything does back to

normal afterward it's like traffic of

contemporary directing traffic and then

making sure

flow smoothly again so interrupts a way

for Hardware to get CPU attention and

the computer uses routines to manage to

handle these

interruptions ensuring that everything

works smoothly despite the sudden poses

in nor in the normal flow of

task so the next slide

implementation basic interrupt mechanism

and a computer works like this so CPU

has special line call to interrupt

request line after each instruction the

CPU checks this line if a device control

signals and interrupt on this line the

CPU reads interrupt number and jumps to

the corresponding interrupt handle

routin using this number as an index the

interrupt

Vector the handle saves State processes

interrupt restores that state and

Returns the CPU to its previous state

however mod operating system require

more advanced interrup handling

features different

handling ability to delay interrupt

handling during critical processing

efficient dispatching quick and

effective selection of right interrup

handle for device multi-level interrupts

capability to discussion between the

high and low priority interrupt and

respond accordingly modeling CPU in

interrupt controller Hardware provide

these features CPUs typically have two

interrupt request line one non maskable

interrupt and another markable interrupt

line used by device controllers

interrupt chaining it techniques when

they interrupt letter points to list of

handlers solving the problem problem of

having more devices than Vector elements

the interrupt Vector designed for CPUs

like Intel processor used different

range of non-maskable and maskable

events additionally interrupts riority

levels all to CPU to manage low and high

priority interrupts

efficiently the system ensure urin work

is handled first and summary interrupts

a crucial for handling a synchronous

events in modeling operating system

there are triggered by device controller

and Hardware fults a priority system

ensur that high priority task can

interrupt lower priority ones efficien

interrup handling is vital for optimal

system performance especially for time

sensitive

processes so storage structure the CPU

can load in struction only from memory

so any program must first be loaded into

memory to run the general proposed

computer run must also program from

reable memory call it main memory it

also call it Ram so memory main memory

commonly is Implement in a semiconductor

technology called Dynamic Random Access

Memory computer use other forms of

memory as well for example the first

program to run on computer power on is

bootst program which then loads the

operating

system since Ram ISAT loses its content

when power is turned off or otherwise

lost we us to hold the bootstrap program

instead of for this some other propose

the computer use

electrically arable progammable read

only memory and another forum for wi

storage that is infrequently reach to is

non

volle storage structure can be organized

into achy based on capacity and excess

time when trade off between size and

speed close to CPU smaller and faster

memory is used the system differ in

speed capacity whether they are volatile

or

nonvolatile vol

storage LS data when power is removed

requiring safekeeping in nonvolatile

storage the top four levels in ychy use

semiconductor memory with NVM device

like flashh memory at the for level

known for Speed flash memory is widely

used in mobile device and increasingly

in long-term storage for laptops desktop

and servers in the text the term

terminology used for storage includes

voltage storage simply refers to as

memory non voltage storage retains data

when power is lost primary focus on

storage secondary storage mechanical

envs example include G gdd optical disc

holographic storage and magnetic type

electrical nvs example include flash

memory V run SD and R mechanical storage

generally large and less expensive for

bite while electrical storage is caser

but smaller and faster a balanced

storage system use cost effective memory

while providing ample and expensive

nonvolatile storage cash may be utilized

to enhance performance Vues significant

difference in excess time or transfer

rate between components

and big part of operating system is

focus handling input output because it's

crucial for system relability and

performance in a compter system uh

various device communicate with each

other using common passway call it a bus

its earlier section we learned about

interrupt driving input or output which

is good for small data transfer but not

efficient for moving large amount of

data

like a nonvolatile storage to under this

we use something called direct memory

access which de withd Dem the device

controller can transfer a whole block of

data directly between the device and

Main memory without Bing the CPU

match so that means only the interrup is

needed per block of data making it more

efficient than having interruptor every

bite especially for slow devices while

device control is managing this task zpu

CPU is free to do other important

work some advanc system use switch

instead of bus for

communication this allows multiple

compon components to talk each other the

same time without competing for Shar bus

in such case di becomes even more more

effective uh so as you see all compan

computer system work

together uh in today Computing landscape

multiprocessor system are prevalent

across Ranch of devices from mobile

gadgets to service typically this system

consists two or more processor each heav

single core this processor sh resource

such computer bars memory and prefer

devices the main advantages

multiprocessor system is increase

through aiming to accomplish more work

in less

time the common approach is s symmetric

multiprocessing where H CPU perform all

task including both operating system

function and user processes while CMP

enables simulation execution of multiple

processes in efficien can be Aur if

processor are not optimally utilized

leading to EO and overload CPUs caral

system design including shared data

structure can address this challenge

alling for damic resource sharing among

processors the definition of

multiprocessor now extend to multicore

system where multiple Computing cores

exist on single chip multi system can be

more efficient than multiple single core

chips due to fast on chips

communication additionally single chip

with multiple core consumes less power

than several single core chips which is

crucial for energy efficient mobile

device and

laptops uh as you see on this figure we

show dual core design with two cores on

same processor chip and this design each

core has its own register set as well as

it own local cache often known as level

one

L1 uh cach notice that uh the level

two cash is local to cheap but is shared

by two processing

CS most architecture adops this approach

combining local and chared caches where

local lower level cash are generally

smaller and faster than higher level

shared caches aside from architecture

considerations such as cach memory and

bus contention a multicore processor

with and core appears to the operating

systems as and standard CPUs this

characteristics put pre pressure on

operating system designers and

application programmers to make

efficient use of this process course to

an issue P so virtually all mod

operating system including Windows maros

Linux as well Android iOS mobile system

support multicore CMP

systems additional uh CPU to

multiprocessor system will increase

computing power however as successed

earlier the concept does not scale very

well and once we add to many inuse

contention for System bus

becomes um bot linic for performance and

performance begins to

degrade an alternative approach insists

to provide hcpu with its own local

memory that accessed via small last

local bus so the CPU are connect by

shared system can interconnect so that's

all CPU share one physical add space

this approach known as nonuniform memory

access on num yeah as you see on this

figure the advantages is that when CPU

access it local memory not only is fast

but there also no contention over the

system

interconnect those numer system can

scale more effectively as more processor

are added a potential drawback with

numer system is increased poy when CPU

must access remote memory across the

system and reconnect creating and

possible performance penalty in other

words for example CPU canot access the

local memory of CPU 3 as quickly as it

can access its own local memory and

slowing down performance breaking system

can minimize thisa penalties through

careful CPU scheduling and memory

management

because NOA system can scale to

accommodate a large number of processors

they are become increasingly popular on

servers as well as high performance

Computing system finally blade servers a

system in which multiple processor

boards input output boards and

networking boards are placed in the same

chases and difference between this and

traditional multiprocessor system is

that each blade processor Bo boot into

independently and its own operating

system some blade server boards

multiprocessor as well which blurs the

line between type of

computers in a sense these servers

consist of multiple independent

multiprocessor

system another type of multiprocessor

system is clustered system which gathers

together multiple

CPUs cluster system are differ from

multiprocessor system describes in that

they are composed of two or more

individual system or not joined together

H not is typically a multicore system

such system are considered Loosely

coupled we should note that the

definition of clustered is not concrete

many commercial and open source package

rels to Define what cluster system is

and what why one form is better than

another the generally accepted

definition is that clustered Computer

Share storage and not closely link it

via local area network or faster

interconnects as Infinity band

clustering uh is usually used to provide

High availability service that is

nervous that will continue even if one

or more system in the cluster fail

generally we obtain High availability by

editing editing level redut dency in the

system a layer of cluster software runs

on the cluster notes H not can monitor

one on all the others if the monitor

machine HS the monitoring machine can

take ownership or storage and restart

the application that we running of valid

machine so the user and clients of

application see only brief interrupt of

service High availability provides

increased reliability which crucial in

many

application the ability to containing

providing service proportion to the

level of surviving hardw is called

graceful

degradation some system go beyond

graceful degradation and call it f

tolerant because it can suffer fure and

single component and still continue

operation H tolerance require mechanism

to all the fur to be dedicated

diagnose it and if the possible correct

it clasing can be structured

symmetrically or symmetrically and

asymmetrical clustering one machine is

hold to be stuned mode while the other

is running the

application the hot stability M machine

does nothing but monitor the active

server that server fails the h stand the

H becomes active server and metri

clustering two or more host are running

applicants and monitoring each other the

structure is obviously more efficient

and uses all of ability Hardware however

it does require that more than one

application can be available to run

since clust consist of several computer

system connect via Network cluster can

also be used to provide high performance

Computing environment such system can

supply significant greater comp uh

computational Power and Signal processor

or CMP system because they can run an

application uh concurrently in all

computers in the cluster the application

must have been written especially to

take advantage of the cluster however

this involves technique known as par

parallelization which device a program

to separate components that run in

parallel or individual cores in a

computer or computer scene cluster

typically this application are designed

to that one each component not in the

cluster has solved it portion of the

program the result from all these notes

are combined into Final Solution other

for cluster include parallel

um uh over white area network and

parallel class all all multiple host

access same data on shared storage

because most operating system lack

support to simulaneously data access by

multiple host parallel cluster usually

require use of special VAR software and

special release of application for

example Oracle real application clust

version of Oracle database it has been

designed to run parallel cluster each

machine runs Oracle and layer of

software tracks access to Shared disk

each machine has full access to all data

in database to provide shared access the

system must also Supply Access Control

and locking to ensure that the no

conflicting operation Ur this function

commonly known as distributed loog

manager it's included in some cluster

technology cluster technology is

changing rapidly some cluster production

support thousand on system and cluster

as well as cluster no separately by

Miles many of these Improvement are made

possible storage area

network this allows many to attach to

Pur storage if the application the data

are stored on sun the cluster software

can assign application to run on any

horse is attached to the sun if the host

fails then any other host can take over

in database cluster do no host can share

same database greatly increasing

performance relability