Data Processing Architectures

The difficulty is in the choiceGeorge Moore, 1900

Architectures

Remote job entry

Local storageOften cheaperMaybe more secure

Remote processingUseful when a personal computer is:

Too slowHas insufficient memorySoftware is not available

Some local processingData preparation

Personal database

Local storage and processingAdvantages

Personal computers are cheapGreater controlBetter interface

DisadvantagesReplication of applications and dataDifficult to share dataSecurity and integrity are lowerDisposable systemsMisdirection of attention and resources

Client/server

Client is typically a Web browserClient initiates requestServer respondsSavings

Ease of use / fewer errorsLess training

Thin client

Diskless computerBrowser-based appsNeed an Internet connection$200-300

Three-tier client/server

Three-tier model

ClientsBrowser with graphical user interface (GUI)

Application serversBusiness and data logic

Data serversDatabaseBackup and recovery services

Advantages of the three-tier model

Security is higher because logic is on the server rather than the PCPerformance is betterAccess to legacy systems and a variety of databasesEasier to implement, maintain, and scale

Evolution of client/server computing

Architecture

Description

Two-tier Processing is split between client and server, which also runs the DBMS.

Three-tier Client does presentation, processing is done by the server, and the DBMS is on a separate server.

N-tier Client does presentation. Processing and DBMS can be spread across multiple servers. This is a distributed resources environment.

Cloud computing

The provision of computing processing and storage resources via the InternetSoftware and hardware resources are sharedResources obtained on demandPart of an evolution rather a revolution in the management of informationClouds, such as time-sharing, have existed for decades

Cloud layers

InfrastructureA virtual server over which the developer has complete controlAmazon

Platform as a serviceA developer can build an application with the provided toolsSalesforce.com

Cloud layers

ApplicationAccess to cloud applicationsGoogle Docs

Collaboration cloudsA special case of application cloudsFacebook

ServiceConsulting and integration

Types of clouds

PublicPrivateCommunityHybrid

Capabilities of clouds

Interface controlTo what extent can customers influence the interface to the cloud?

Capabilities of clouds

Location independenceUbiquitous access

Capabilities of clouds

Sourcing independenceCan change suppliers easily at low costA goal rather than always a reality

Virtual business environmentsSpecial needs systems can be built quickly and later abandoned

Rapid elasticityScale up and down as required• Easier to scale up than down

Strategic risksRisk Description

Demand Fluctuating demand or market collapse

Inefficiency Inability to match competitors’ unit costs

Innovation Not innovating as well as competitors

Scaling Not scaling fast and efficiently enough to meet market growth

Control Inadequate procedures for acquiring or managing resources

Demand

Fluctuating demand or market collapseUbiquity enables serving customers everywhereElasticity to handle excessive demand

Inefficiency

Inability to match competitors’ unit costsCloud computing is generally cheaperSingle service center for all customersEmployees can work at home or on the roadLow cost testing of system innovations

Innovation

Not innovating as well as competitorsInterface control could be issue for innovationUbiquitous access makes it easier to engage customers and employees in product improvement

Scaling

Not scaling fast enough and efficiently enough to meet market growthA firm can use the cloud’s elasticity to quickly acquire new storage and processing resources for digital productsIt can take advantage of sourcing independence to use multiple clouds

Control

Inadequate procedures for the acquisition or management of resourcesA well-designed interface is a control mechanism

Thinking

Most people think of cloud computing as an opportunity to lower costs by shifting processing from the corporate data center to a third partyMore imaginative thinkers will see cloud computing as an opportunity to gain a competitive advantage

Clouds & strategic risks

Risk/Capability Demand

Inefficiency

Innovation

Scaling

Control

Interface control ✔ ✔Location independence ✔

Sourcing independence ✔ ✔

Virtual business environment

✔ ✔

Ubiquitous access ✔ ✔ ✔

Rapid elasticity ✔ ✔

Distributed database

Communication charges are a key factor in total processing costTransmission costs increase with distance

Local processing saves money

A database can be distributed to reduce communication costs

Distributed database

Database is physically distributed as semi-independent databasesThere are communication links between each of the databasesAppears as one database

A hybrid

Architecture evolvesOld structures cannot be abandonedNew technologies offer new opportunities

Ideally, the many structures are patched together to provide a seamless view of organizational databasesDistributed database principles apply to this hybrid architecture

Fundamental principles

TransparencyNo reliance on a central siteLocal autonomyContinuous operationDistributed query processingDistributed transaction processing

Fundamental principles

Replication independenceFragmentation independenceHardware independenceOperating system independenceNetwork independenceDBMS independence

Independence

Horizontal fragmentation

Vertical fragmentation

ReplicationFull replication

Tables are duplicated at each of the sitesIncreased data integrityFaster processingMore expensive

Partial replicationIndexes replicatedFaster queryingRetrieval from the remote database

Key points

There are basic data processing architecturesN-tier client/server dominates todayCloud computing offers cost savings and strategic opportunitiesDatabases can be distributed to lower communication costs and improve response time