HI-600: Analysis and Design of Health Information Systems

Design: Part IIArchitecture Design

Architectural Components• Software Components• Data Storage• Data Access Logic• Application Logic• Presentation Logic

• Hardware Components• Client Computers• Servers• The network

Client-Server Architectures

Balances processing between clients and server(s)• Client: Presentation logic• Server(s): Data storage and data access

logic• Thick (fat) / thin clients• Thick/fat client: All or most application logic• Thin client: Small part of the application logic

Client-Server Architectures (con’t)• Scalable• Can support different types of clients and

servers through middleware• The logical software components can be

independent• Server failure only affects dependent

applications

• Software development is more complex.

Client-Server Tiers

• 2-Tiered

• 3-Tiered

• N-Tiered

Less Common Architectures

Server-BasedArchitectures

Client-BasedArchitectures

Advances in Architecture Configurations

• Virtualization refers to a creation of a virtual device or resource, such as a server or storage device

• Cloud computing – everything from computing power to computing infrastructure, to applications can be delivered as a service wherever and whenever needed

Comparing architecture options: Often the current infrastructure restricts the choice of architecture; client-server architectures are more cost- effective

CREATING AN ARCHITECTURE DESIGN• Operational Requirements• Technical Environment, System Integration, Portability,

Maintainability• Performance Requirements• Speed, Capacity, Availability and Reliability

• Security Requirements• System Value, Access Control, Encryption and

Authentication, Virus Control• Cultural and Political Requirements• Multilingual, Customization, Unstated Norms, Legal

Operational Requirements

Performance Requirements

Security Requirements

Cultural and Political Requirements

Designing the Architecture

HARDWARE AND SOFTWARE SPECIFICATION

• Software• Operating System• Special Software

• Hardware• Clients• Each server• Peripheral Devices• Backup Devices• Storage Devices

• Network

Factors in hardware and software selection• Functions and Features• Performance• Legacy Databases and Systems• Hardware and OS Strategy• Cost of Ownership• Political Preferences• Vendor Preferences

SUMMARY• Application architecture• Client-server architecture• Advances in architecture configurations:

virtualization and cloud computing• Architecture Design• Nonfunctional requirements

• Hardware and software specification• A document that describes what hardware and

software are needed to support the application