1. Enterprise Systems Architectures

2. Enterprise Systems Architectures
Introduction
This lesson introduces some concepts on systems and technology to better understand ERP issues
- Computing
- Networks
Databases
Software
Software Choices and Requirements Analysis

3. Computing Initially enterprise computing was running on mainframes
Later (1993) the concept of client server technology were introduced
With mainframe computing all computing operations is done via a single computer, with users connecting via terminals
Client server technology enable users to have some computing capabilities
The computing and storage can be shared between the client and the server
Client = user’s computer, while server is a centrally located computer
(O‘Leary, 2012)

4. Computing
Thin/fat client refers to processing capability of the client
Thin client refers to a client with minimal computing capabilities
Fat client represent a client with greater computing capabilities
In a three-tier architecture there are three/several servers with differerent tasks
For example SAP R/2 was designed for mainframe environment, while R/3 uses the client server technology
(O‘Leary, 2012)

5. Computing
Mainframe architecture
(Linux Journal, 2008)

6. Computing
Two-tier architecture
(Linux Journal, 2008)

7. Computing
Three-tier architecture
(Linux Journal, 2008)

8. 3 Tier Architecture Example of ERP System

9. Networks
In a client/server setup there is a network between clients and servers
Some concepts
LAN‘s, Intranets, Extranets
Bandwidth
Standards
Security ( eg. SAProuter & encryption)
Network bandwidth should be enough to handle transactions flow from the ERP, as well other application activities running on the same network
Communication within ERP uses standard protocols eg. TCP/IP

10. Databases
Most ERP systems uses databases to handle enterprise transactions and data
Some still run on „flat file“ databases
Flat files are two-dimensional files that are easy to use but not good to model the business events
Another problem with this approach is the duplication of data
Relational database consist of a set of tables that are linked to each other
Relational databases are more robust and suitable for a wide range of enterprise events.
A Data Warehouse combine data from various sources into a single database for statistical purposes
(O‘Leary, 2012)

11. Software An ERP system is a software
Software issues to be considered include:
Operating systems
Legacy software
Package software
Database Management System
(O‘Leary, 2012)

12. Software Choice and Requirements Analysis
Software choice: Cost-Benefit Analysis
To determine the right software for an organization requires a thorough cost-benefit analysis to be conducted
Benefits can be difficult to determine and some costs are hidden
Costs and benefits can be realized after the system have been used for a while
(O‘Leary, 2012)

13. Software Choice and Requirements Analysis
Two models that represent organization’s processes
“As Is” – model the current processes
“To Be” – model the future/preferred processes
The models can help provide the basis to judge between different software

14. References
O’ Leary, D. (2012). Enterprise Resource Planning Systems. United Kingdom: Cambridge University Press
Linux Journal. (2008). Three-Tier Architecture. Retrieved July 05, 2009, from