Download Chapter 5 - High Point University

Chapter 5
Distributed Systems:
The Overall Architecture
Presented by: Matt Carver
Amber Martin
Jon Tucker
Part I
4 Attributes of Distributed
Systems
1.
Where is the processing done?
Distributed processing is the ability for more than one
interconnected processor to be operating at the same time, typically
for processing an application on more than one computer.
2.
How are the processors and other devices interconnected?
Connectivity among processors means that each processor in
a distributed system can send data and messages to any other
processor through electronic communications links. A good
structure for reliable distributed systems has at least 2 independent
paths between any two nodes, enabling an automatic alternate
routing in case one node is down.
4 Attributes of Distributed
Systems (cont.)
3.
Where is the information stored?
Distributed databases are being defined at least 2 ways. One
divides a database and distributes its portions throughout a system,
without duplicating the data. A network administrator can access
any portion from any node (authorization). The second type of
distributed database stores the same data at several locations, with
one site containing the master file.
4.
What rules or standards are used?
Systemwide rules mean that an operating discipline for the
distributed system has been developed and is enforced at all times.
These rules govern communication between nodes, security, data
accessibility, program and file transfers, and common operating
procedures.
Part II
6 Types of Distributed Systems
1. Host-Based Hierarchy
•
•
Mainframe (HP 3000) that does MRP
Terminals are connected to the mainframe
6 Types of Distributed Systems (Cont.)
2. Decentralized Stand-Alone Systems
•
Big company with 3 departments
• Accounting, Manufacturing, and IT
• “sneaker net”
• Walk around from dept to dept with a floppy
6 Types of Distributed Systems (Cont.)
3. Peer-to-Peer LAN-Based Systems
• PCs, print servers, and gateways
• Everyone is equal….no superior system
• No hierarchy
6 Types of Distributed Systems (Cont.)
4. Hybrid Enterprisewide Systems
• LAN (High Point)
• 2 other LANs (Winston and Greensboro)
6 Types of Distributed Systems (Cont.)
5. Client-Server Systems
• Old days, one-tier model, housed data, logic, and presentation
• Company hired 2 people (accountants) to access the same
data, the company had to go to 2-teir
• Marsh has a program called Ultipro.
• SQL Server housed Ultipro’s data
• 2 client PCs can access the server to get the data at the same
time = 2 tier
• In the future, we may have to develop an application that
needs access not only to the Ultipro data, but to the logic…we
would implement a 3 tier approach
• SQL Serv still holds Ultipro’s data, and we put Ultipro’s logic
on Marsh 1NT
6 Types of Distributed Systems (Cont.)
6. Internet-Centric Computing
•
•
Same as Host based
system
Use TCP/IP instead of
serial connections
Part III
Roles and Components of an
Enterprise Architecture Framework
1.
2.
3.
4.
5.
6.
Planner - Scope
Owner - Enterprise
Model
Designer – Information
System Model
Builder – Technology
Model
Subcontractor Components
Consumer/User –
Functioning System
1.
2.
3.
4.
5.
6.
Data – what?
Function – how?
Network – where?
Who – people
When – time
Why – motivation
Use of the Framework

Models are important because:




Allow proper evaluation of the packages
Help builders align with what owners want
Help companies realize what changes need to be
made when they move to a new model
Problems occur when IS or users bring in a
package that follows a different data model

If the rules in that model are inconsistent with the
rules in the company, then a lot of time will be
wasted fixing the package
Part IV
Four Types of IT Investments
1.
2.
Strategic – aim to change the
way a firm competes, the
products or services it offers, or
how it intends to increase
revenues
Informational – provide
information employees need to
manage and control the
enterprise
Four Types of IT Investments
3.
4.
Transactional – support operational
management; intended to cut
operating costs by substituting
capital for labor so higher volumes
can be handled without huge
increases in staff
Infrastructure – provide the base
foundation of IT capability, supports
all other levels applications
Part V
What is an IT Infrastructure?



An IT infrastructure is the foundation of an
enterprise’s IT portfolio
Provides both the managerial and technical
expertise to successfully manage an enterprise
Linked to other industry infrastructure systems such
as banking payment systems and airline reservation
systems
Elements of an IT Infrastructure

Can include but not limited to:
- Company-wide networks
- Data Warehouses
- Large-Scale Computing Facilities
- Electronic Data Interchange
- R&D for identifying emerging technologies
Three views of Infrastructure
1. Economies of scale (Utility)
2. Support for business programs (Dependent)
3. Flexibility to meet changes in the
marketplace (Enabling)
Utility View




Companies that view their infrastructure as a
utility see it as an unavoidable service
Expected benefits from cost saving achieved
through economies of scale
Organizations with this view try to minimize
expenses of the infrastructure
Only results in lowering cost, not
reengineering the business
Dependent View




Focuses on short-term business benefits
Firms with this view see the network as
critical
This view smoothes the way for simplifying
business procedures
Infrastructure is seen as a business expense
Enabling View





Most strategic of the three views
Focuses on developing and continually
modifying the infrastructure
Aligns the infrastructure with the business
strategy
Primary benefit is long-term flexibility
Infrastructure cost are seen as business
investments rather than business expenses
THE
END