two histories of enterprise computing
DESCRIPTION
Two histories of enterprise computing. A history of enterprise computing I: Calculation systems. 1950s-80s Single purpose Eliminate tedious human work Examples: Payroll, General ledger, Inventory Technology used: Mainframes, magnetic tapes, batch processing. - PowerPoint PPT PresentationTRANSCRIPT
Two histories of enterprise computing
1
2
A history of enterprise computing I: Calculation systems 1950s-80s Single purpose Eliminate tedious human work Examples: Payroll, General ledger, Inventory Technology used: Mainframes, magnetic
tapes, batch processing
3
A history of enterprise computing II: Functional systems
1975-2001 (say) Use computers to improve operations Applications: Human resources, order entry,
manufacturing resource planning Technologies: Mainframes, PC’s, LAN’s
4
Functional systems Typically contained within a department Islands of automation Applications independently developed and deployed Driving force: availability of mini-computers
5
Functional system applications Human resources System Accounting and finance systems Sales and marketing System Operations management System Manufacturing Systems
6
History part III: Pressures on business forced integration It becomes less and less possible to think about isolated
systems. The world is becoming more joined up.
eCommerce Need to allow access to customers
Out sourcing Need to integrate with 3rd party systems
Mergers and acquisitions Regulation
Post-9/11 and Sarbanes-Oxley requires must better integration and reporting
Post-credit crunch regulation still emerging
7
Organisational systems
2000-date (say) Use computers to drive efficiency and support control
across organisations and beyond to partners and suppliers
Applications: Risk management, customer relationship management, supply chain management
Technologies: Middleware, business intelligence, data integration technologies
8
Types of Organizational information Systems Administrative systems Scheduling / Transaction systems Value oriented systems Reporting and controlling systems Analysis and information systems Planning and decision support systems
Exercise Each group chose a different business function within
the organisation.
Define how a customer will be represented. Personal details 1 or more details specific to your selected business function
9
10
Problems with function based application Sharing of data between systems
Data duplication Data inconsistency
Applications that don’t talk to one another Limited or lack of integrated information
Isolated decisions lead to overall inefficiencies Increased expenses
Stovepipe systems
HR Sales
Manufacturing
Cloud computing On-demand access to a shared pool of
configurable computing resources
Exercise: Is cloud computing the next stage beyond
organisational systems?
11
12
An architectural history of computing 1 tier architecture
Presentation, application logic, and resource management were merged into a single tier
Often associated with ‘legacy’ mainframe systems 2 tier architecture
Separation of presentation tier from other 2 tiers (app + resource)
'client/server' systems 3 tier architecture
Separation of application logic and resource management tier
13
Tiers of an architecture
<html>...</html>
Presentation tier
Application logic tier
Resource management tier
Client
info
rmat
ion
syst
em
Visualise
Calculate
Store
Browser
14
Tiers of an architectureBrowser
Presentation tier
Application logic tier
Resource management tier
Client
info
rmat
ion
syst
em
How the data should appear to the user and how the user should interact with the interface
The sequence of screens presented to the user and the data entered by the user
The starting point for most tasks E.g. Entering an order,
adding an employee
15
Tiers of an architecture
Presentation tier
Application logic tier
Resource management tier
Client
info
rmat
ion
syst
em
Data Processing (Business Logic & calculation) The algorithms are
implemented in this tier This tier is often referred to
as Services, Business logic, Business rules, Server
Were the ‘work’ of the application occurs E.g. Calculating the value of
the order, creating the record to be entered into the employee database
Calculate
16
Tiers of an architecture
Presentation tier
Application logic tier
Resource management tier
Client
info
rmat
ion
syst
em
Deals with and implements different data sources of Information Systems The 'data layer' in a
restricted interpretation as in JEE or Database Management System
Can also be a gateway to recursively using other Information systems
Where the business data which will persist is stored E.g. The completed order,
the employee record
Store
Adding tiersAdvantagesWith growing number of tiers
one gains: Flexibility
Add servers in each tier to meet demand
Functionality Introduce new functionality to each
tier without changing the other tiers Possibilities for distribution
Able to locate servers near to main users
Disadvantages Each tier increases
communication costs Network traffic increases
Complexity rises leading to higher cost and risk Higher complexity of development:
Now need to consider where functionality is located and how to communicate between tiers
Higher complexity of management and tuning
Redundancy increases Potentially have too many servers in
each tier which will be under-utilised
17
18
Design of 1 – Tier Architecture
Presentation layer
Application logic layer
Resource management layer
Client
info
rmat
ion
syst
em
Presentation, application logic, and resource management were merged into a single tier
Advantages: Simplicity easy to optimise performance on a single
server no compatibility issues between tiers no client development, maintenance and
deployment cost
Disadvantages: Difficult to manage/modify Poor scaling on system is on a single system lack of qualified programmers for these
systems (for 1-tier ‘legacy’ systems)
19
2 - Tier Architectures
fig 1.7 p.12
Client
Info
rmat
ion
syst
em
Resource management layer
Application logic layer
Serv
er
Presentation layer
20
2 - Tier Architectures
Separation of presentation layer from other 2 layers (app + resource)
Client/server systems with thin clients/fat clients Must use RPC (Remote Procedure Call) to communicate between
client and server tiers Need for standardisation for inter-tier communication
Advantages portability no need for context switches or calls between component for key
operations Disadvantages
Increased complexity Risk of incompatibilities between clients developed at different
times
21
3 - Tier Architectures
info
rmat
ion
syst
em
resource management layer
application logic layer
middleware
client
presentationlayer
22
3 - Tier Architectures
Separating RM (resource management) from application logic layer
Additional middleware layer between client and server integration logic application logic
Lead to the introduction of clear RM layer interfaces
Good at dealing with integration of different resources
23
Business logic resides in middle tier Alternatives
Client tier leads to Fat clients Reimplementing it for each different type of client Redistributing clients after each software update
Data tier leads to Vendor and technology dependence grows Different applications have different needs for the same data Performance issues in resource usage
24
3 - Tier Architectures
Advantages scalability by running each layer on a different server scalability by distributing application logic tier across many
servers Flexibility to introduce multiple application logic servers running
different application logic
Disadvantages performance loss if distributed widely over intranet or internet Complexity of managing 3 tier systems
25
3 - tier Architectures
info
rmat
ion
syst
em
resource management layer
application logic layer
middleware
client
presentationlayer
GUI clientsC++, VB, Java
MiddlewareServer
Databases Legacy Systems
26
Middleware Middleware refers to the software which is common to multiple
applications and builds on the network transport services to enable ready development of new applications and network services.
Middleware typically includes a set of components such as resources and services that can be utilised by applications either individually or in various subsets. Examples of services: Security, Directory and naming, end-to-end
quality of service, support for mobile code. Examples:
OMG’s CORBA J2EE - Java 2 Enterprise Edition Microsoft’s .Net
27
Middleware features Allows communication
through a standard language across different platforms between legacy and modern applications
Make 3-tier architecture safe by ensuring data/communication between tiers is protected by taking care of transactions between servers data conversion authentication communications between computers
28
Middleware features Makes it easier to write 3-tier applications by providing
runtime environment for components in the middle-tier Component lifecyle and management Transaction, event and security services Provides connections to databases, mainframes and legacy
systems
Separates client-tier from the data source Clean separation of user-interfaces and presentation logic from
the data source
29
n - tier
3 tier systems rarely exist as most systems connect to other applications or databases to complete the processing task E.g. An airline booking system connects with VISAcard systems to collect
payment N-tier extends 3-tier to allow for connections to these additional tiers
How many tiers?
Adding tiersAdvantagesWith growing number of tiers
one gains: Flexibility
Add servers in each tier to meet demand
Functionality Introduce new functionality to each
tier without changing the other tiers Possibilities for distribution
Able to locate servers near to main users
Disadvantages Each tier increases
communication costs Network traffic increases
Complexity rises leading to higher cost and risk Higher complexity of development:
Now need to consider where functionality is located and how to communicate between tiers
Higher complexity of management and tuning
Redundancy increases Potentially have too many servers in
each tier which will be under-utilised
30
Exercise Why is performance a harder issue to resolve with n-tier
systems than with 1-tier systems?
Classify cloud computing in terms of the number of tiers
31
Classification of Information systems
33
Organisational Hierarchy
Organisational Structure and departmental organisation
Business processes
Classification of Information Systems
34SALES & MANUFACTURING FINANCE ACCOUNTING HUMAN
Types of system Groups Served
STRATEGIC LEVEL SENIOR MANAGERS
MANAGEMENT LEVEL MIDDLE MANAGERS
OPERATIONAL OPERATIONALLEVEL MANAGERS
KNOWLEDGE LEVEL KNOWLEDGE &DATA WORKERS
RESOURCESMARKETING & ENGINEERING
Information System from business perspective
35
Four General Kinds of System Operational-level systems
support operational managers by monitoring the day-to-day’s elementary activities and transactions of the organization. e.g. TPS.
Knowledge-level systems support knowledge and data workers in designing products,
distributing information, and coping with paperwork in an organization. e.g. KWS, OAS
Management-level systems support the monitoring, controlling, decision-making, and administrative
activities of middle managers. e.g. MIS, DSS
Strategic-level systems support long-range planning activities of senior management. e.g.
ESS
36SALES & MANUFACTURING FINANCE ACCOUNTING HUMAN
Types of system Groups Served
STRATEGIC LEVEL SENIOR MANAGERS
MANAGEMENT LEVEL MIDDLE MANAGERS
OPERATIONAL OPERATIONALLEVEL MANAGERS
KNOWLEDGE LEVEL KNOWLEDGE &DATA WORKERS
RESOURCESMARKETING & ENGINEERING
Horizontal information flows
Ver
tical
info
rmat
ion
flow
s
Information System from business perspective
37
Management Structures and Information Requirements
Higher up the pyramid, the less structured the decision Less defined External orientation More summarized information Future oriented Less frequent Less accurate
Lower down the pyramid, the more structured the decision More defined Internal orientation More detailed information Historical More frequent More accurate
38
A Framework for classification ofIT system
• Executive Support Systems (ESS)• Management Information Systems (MIS)• Decision Support Systems (DSS)• Knowledge Work Systems (KWS)• Office Automation Systems (OAS)• Transaction Processing Systems (TPS)
39
Transaction Processing Systems Transaction Processing Systems (TPS)(TPS)
Computerized system that performs and records the Computerized system that performs and records the daily routine transactions necessary to conduct the daily routine transactions necessary to conduct the business; these systems serve the operational level of business; these systems serve the operational level of the organizationthe organization
• TYPE: Operational-levelTYPE: Operational-level• INPUTS: transactions, eventsINPUTS: transactions, events• PROCESSING: updatingPROCESSING: updating• OUTPUTS: detailed reportsOUTPUTS: detailed reports• USERS: operations personnel, supervisorsUSERS: operations personnel, supervisors• DECISION-MAKING: highly structuredDECISION-MAKING: highly structured
EXAMPLE:EXAMPLE: payroll, accounts payable payroll, accounts payable
40
Typical Applications of TPS
TYPE OF TPS SYSTEMSales/ Manufacturing! Finance/ Human Other typesmarketing production accounting resources (e.g., university)systems systems systems systems
Major functions Sales management Scheduling Budgeting Personnel recard Admissionsof system Market research Purchasing General ledger Benefits Grade records
Promotion Shipping/receiving Billing Cornpensation Course recordsPricing Engineering Cost accounting Labor relations AlumniNew products Operations Training
Major Sales order Materials resource General ledger Payroll Registration systemapplication information system planning systemssystems Market research Purchase order Accounts Employee records Student transcript
system control systems receivable/payable systemPricing system Engineering Budgeting Benefit systems Curriculum class
systems control systemsQuality control Funds management Career path Alumni benefactorsystems systems systems system
41
Office Automation Systems Office Automation Systems (OAS)(OAS)
Computer system, such as word processing, electronic mail system, and scheduling system, that is designed to increase the productivity of data workers in the office.
• TYPE: Knowledge-levelTYPE: Knowledge-level• INPUTS: documents, schedulesINPUTS: documents, schedules• PROCESSING: document management, scheduling, communicationPROCESSING: document management, scheduling, communication• OUTPUTS: documents; schedulesOUTPUTS: documents; schedules• USERS: clerical workersUSERS: clerical workers
EXAMPLE:EXAMPLE: document imaging system document imaging system
42
Decision Support Systems Decision Support Systems (DSS)(DSS) Information system at the management level of an organization that combines data and sophisticated analytical models or data analysis tools to support semi-structured and unstructured decision making.
•TYPE: Management-levelTYPE: Management-level• INPUTS: low volume dataINPUTS: low volume data• PROCESSING: simulations, analysis PROCESSING: simulations, analysis • OUTPUTS: decision analysisOUTPUTS: decision analysis• USERS: professionals, staff managersUSERS: professionals, staff managers• DECISION-MAKING: semi-structuredDECISION-MAKING: semi-structured
EXAMPLE:EXAMPLE: sales region analysis sales region analysis
43
Characteristics of Characteristics of Decision-Support SystemsDecision-Support Systems1. DSS offer users flexibility, adaptability, and a quick response.
2. DSS operate with little or no assistance from professional programmers.
3. DSS provide support for decisions and problems whose solutions cannot be specified in advance.
4. DSS use sophisticated data analysis and modelling tools.
44
Management Information Management Information Systems (MIS)Systems (MIS)
Information system at the management level of an organization that serves the functions of planning, controlling, and decision making by providing routine summary and exception reports.
• TYPE: Management-levelTYPE: Management-level• INPUTS: high volume dataINPUTS: high volume data• PROCESSING: simple models PROCESSING: simple models • OUTPUTS: summary reportsOUTPUTS: summary reports• USERS: middle managersUSERS: middle managers• DECISION-MAKING: structured to semi-structuredDECISION-MAKING: structured to semi-structured
EXAMPLEEXAMPLE: annual budgeting: annual budgeting
45
Characteristics of Management Characteristics of Management information Systemsinformation Systems
1. MIS support structured decisions at the operational and management control levels. However, they are also useful for planning purposes of senior management staff.
2. MIS are generally reporting and control oriented. They are designed to report on existing operations and therefore to help provide day-to-day control of operations.
3. MIS rely an existing corporate data-and data flows.4. MIS have little analytical capability.5. MIS generally aid in decision making using past and present
data.6. MIS are relatively inflexible.7. MIS have an internal rather than an external orientation.
46
Executive Support Systems (ESS)Executive Support Systems (ESS) Information system at the strategic level of an organization that address unstructured decision making through advanced graphics and communications.
TYPE: Strategic levelTYPE: Strategic level• INPUTS: aggregate data; internal and externalINPUTS: aggregate data; internal and external• PROCESSING: interactivePROCESSING: interactive• OUTPUTS: projectionsOUTPUTS: projections• USERS: senior managersUSERS: senior managers• DECISION-MAKING: highly unstructured DECISION-MAKING: highly unstructured
EXAMPLEEXAMPLE: 5 year operating plan: 5 year operating plan
47
A single software package like Microsoft Office or even an application like Microsoft Excel could be classified as any or all of the following: DSS, TPS, MIS, or ESS (albeit, a trivial ESS, DSS, etc.)
When considering classification, consider how the tool is used, not what it could be used for.
A tools meets a need posed by the enterprise A service is provided by the tool is a solution.
However, the world is not that However, the world is not that straight forwardstraight forward
48
Classification of IT Systemby Organizational Structure
Departmental Information Systems Enterprise Information System Inter-organizational Systems
SWIFT (mostly network level) SABRE
49
Classification of IT Systemby Functional Area
The accounting information system The finance information system The manufacturing (operations, production)
information system The marketing information system The human resources information system
50
e.g. Sales & Marketing Systems Systems that help the firm identify customers for the firm’s
products or services, develop products and services to meet customer’s needs, promote products and services, sell the products and services, and provide ongoing customer support.
EXAMPLESSystem Description Organizational LevelOrder processing Enter, process, and track orders OperationalMarket analysis Identify customers and markets using Knowledge
data on demographics, markets,consumer behavior, and trends
Pricing analysis Determine prices for products Managementand services
51
Classification of IT system by Business Processes
A business process is a set of coordinated tasks and activities, conducted by both people and equipment, that will lead to accomplishing a specific organizational goal.
Business process management (BPM) is a systematic approach to improving those processes.
52
Examples of Business ProcessesFunctional Area Business ProcessManufacturing and production Assembling the product
Checking for qualityProducing bills of materials
Sales and marketing Identifying customersMaking customers aware of the productSelling the product
Finance and accounting paying creditorsCreating financial statementsManaging cash accounts
Human resources Hiring employeesEvaluating employees' job performanceEnrolling employees in benefits plans