Transcript
Architecture MIS 5003
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Architecture Components and the relationships among them. Program architecture Application architecture Enterprise system architecture
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Program Architecture A part of the system design process Define sub-programs Define program modules Define data stores Specify the calling sequences e.g. System flow charts & Functional Hierarchy Diagrams 3
Application Architecture Structure of a particular application. Databases and program components Devices and operating environments on which these run Communication links among the devices
Application architecture must take into account the enterprise architecture and its current load. 4
Enterprise Architecture Structure of clients, servers, operating environments, networks and security used to support the enterprise applications. Usually too expensive to be justified by a single application Generally defines standards to which applications must adhere 5
What is Enterprise System Architecture? Narrow - Hardware, Operating System and other System Software, DBMS & Network Broad - Add: Application Programs, Design Tools, Physical Layout, Policies and Procedures 6
Principles for the Ideal Architecture Open, High Performance/Cost Immediate Availability Infinitely Scaleable Completely Secure, Failure Free Inexpensive, Rapid Change High Level of User Control Little or no Training Required 7
The ISSUE for this Class How does a person make “good” decisions in selecting architectures or components
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Different Views Business View Reach, range, response & risk
Conceptual View Nodes, application mix, performance parameters & security plan
Design View Network design, server specifications, operating systems and middleware, program decomposition, segmentation and firewalls 9
Business View Reach: locations for delivery Range: application mix Response: deferred, real time, interactive Risk: threat*success*cost 10
Conceptual View Translation of user needs into technical specifications. Functionality at each node Data and process demands for the system Dialog expectations and processing turnaround needs Security objectives 11
Design View Distribution of functions across nodes Location of data and access procedures Node specifications (or specifications of existing nodes) Location of firewalls and use of added security such as encryption Link specifications and interconnection design 12
Base Architecture Mainframes -- few new applications; used mostly for legacy ones Client/Server -- most new applications; main direction for next several years NetCentric -- important new area; will it take over some or all Combinations -- case for most systems 13
Mainframe Architecture -1990 Proprietary $100,000/MIPS Years to Deliver Difficult to Scale Change Difficult Remote Users Works Well! 14
Mainframe Architecture in 2000 $2,000 per MIPS Open architecture Now a Network Server as well Short Delivery time Excellent operating systems & support Increased scalability Large set of existing programs
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Distributed System Characteristics - 1999 Open, <$100/MIPS Short Availability Good Scalability More User Control More Likely to Fail Costly Training Costly to Maintain Policy control Issue 16
Distributed Architectures Amount of Work
Server
Client Mainframe Systems
Netcentric Thin Client
Fat Client
Stand Alone PC 17
Telecommunications Essential Link for Distributed Systems Area and Control Local (LAN) - nearby, private Wide (WAN) - further away, public Specifications - capacity or speed Technology
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NetCentric Systems Intranets - Standard Browser & Protocol (TCP/IP) Central Control of Intranet, some Applications, some Servers Fast Approach to a Global System Allows Local Autonomy 19
Electronic Commerce (EDI) Issues: Cost, Elapsed Time, Access Basic EDI-- electronic transactions, data flows, reports Electronic markets and products Electronic Outsourcing Electronic Virtual Firms 22
Electronic Commerce (B2C) Issues: how do we use it. Reliability, accessibility, security. Electronic effects on traditional brick and mortar business. Advertisement, electronic registration, transaction processing, customer relationship management. 23
Broad Issues For Architectures Business Functions Company Preferences Interoperability Security Reliability / Availability System Management Tools Cost / Effectiveness 24
Company Culture IS Priority of the Responsible Manager Perceived Performance of Current IS Risk & Failure Tolerance Change Tolerance Desire to Lead Experience Base Skills Base 25
Base Technologies I High Performance/Cost, multi-chip Servers Relational &/or Object DBMS Fast, switched Ethernet, Routers Internet II, faster, lower cost WANS Electronic signatures, high security 26
Base Technologies II Multiple Architecture Structures High Levels of Competition High Innovation Rates Increasing Business and Strategic Importance of IS Increasing IS visibility 27
Security in Distributed Systems Passwords - one or multiple Authentication Access Control Lists Firewalls Encryption & Electronic Signatures Security Failure Detection Damage Control and Correction 28
Availability Protection Physical Control / Protection Shadow Systems / Locations Mirror Databases RAID - Redundant Arrays of Inexpensive Disks Fault Tolerant Servers System Backups - Secure Storage 29
Vendors & Outsourcing General Opinion -- consultants, other users, open literature Direct Prior Experiences Specifics-- Warranty Experience, Customer Service, Response Time, Update Policy, Industry Position, Longevity 30
Future Forecasts Technologies Vendors IS Skills Business Functions Markets
You have no future!
CIO
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Futures I Multiple Architectures Widespread Electronic Commerce Increased Competition - Downsize, Reorganize, Merge, Fail System Design - Still Difficult, Expensive and High Risk 32
Futures II Continue New Technologies Fast/Large everything, Voice, nonsilicon processors/storage Hardware Cost/Performance Telecommunications improvements Reduce labor cost - - CASE, Package Programs, Outsourcing. 33
Technology Assessment Winning technologies generally have: Low cost Early introduction Good enough performance Market share
Most technology innovations have evolved into one or two dominant products over time. 34
