System Development Techniques Individual Assignment

System Development Techniques

Diploma in Information Technology

Lesson 17

Learning outcomes After studying this chapter and the recommended reading, you should be able to:

• Describe the deployment activities • List various approaches to data conversion and

system deployment • Discuss the advantages and disadvantages of the

approaches • Describe training and user support requirements for

new and operational systems

Deployment

Deployment Activities

• Deployment activities – involve many conflicting constraints

• cost, • need to maintain positive customer relations, • need to support employees, • logistical complexity, • overall risk to the organization.

– main activities • UAT • Converting and Initializing Data • Training Users • Configuring the Production Environment

Converting and Initializing Data

• Converting and Initializing Data – An operational system requires a fully populated database

to support ongoing processing. • For example, online order-entry and management functions rely

on stored information about products, promotions, customers, and previous orders.

– Developers must ensure that such information is present in the database at the moment the subsystem becomes operational.

Converting and Initializing Data

• Converting and Initializing Data – Data needed at system start-up can be obtained from

these sources: • Files or databases of a system being replaced • Manual records • Files or databases from other systems in the organization • User feedback during normal system operation

Converting and Initializing Data

• Converting and Initializing Data – Reusing Existing Databases

• Most new information systems replace or augment an existing manual or automated system.

• Pluck the old system out and attached the new system into the existing database.

• In the simplest form, old system’s database is used directly by the new system with little or no change to the database structure.

• For upgraded systems, some changes to database content are usually required. Typical changes include adding new tables, adding new attributes, and modifying existing tables or attributes.

Converting and Initializing Data

• Converting and Initializing Data – Reloading Databases • More complex changes to database structure may

require creating an entirely new database and copying and converting data from the old database to the new database. • Utility programs supplied with the DBMS are used to

copy and convert the data. • In more complex conversions, implementation staff

must develop programs to perform the conversion and transfer some or all of the data.

Training Users

• Training Users – is an essential part of any system deployment project – two type of users

• end users – people who use the system from day to day to achieve the

system’s business purpose. • system operators

– people who perform administrative functions and routine maintenance to keep the system operating.

Training Users

• Training Users – Documentation and other training materials • usually developed before formal user training begins. • Each documentation type is targeted to a different

purpose and audience. • Documentation can be loosely classified into two types:

– System documentation. » Descriptions of system requirements, architecture, and

construction details – User documentation.

» Descriptions of how to interact with and use the system

Training Users

• System Documentation – provides information to developers and other technical

personnel who will maintain and upgrade the system. – generated throughout the SDLC by each core process and

many development activities. – System documentation developed during early project

iterations guides activities in later iterations, and documentation developed throughout the SDLC guides future system maintenance and upgrades

Training Users

• User Documentation – provides ongoing support for end users of the system. – describes routine operation of the system, including such

functions as data entry, output generation, and periodic maintenance.

– Topics typically covered include the following: • Software start-up and shutdown • Keystroke, mouse, or command sequences required to perform

specific functions • Program functions required to implement specific business

procedures (e.g., the steps followed to enter a new customer order)

• Common errors and ways to correct them

Configuring the Production Environment

• Configuring the Production Environment – Modern applications are built from software components

based on interaction standards, such as • Common Object Request Broker Architecture (CORBA), • Simple Object Access Protocol (SOAP), • Java Platform Enterprise Edition (Java EE). • Microsoft .NET

– Each standard defines specific ways in which components locate and communicate with one another.

Configuring the Production Environment

• Configuring the Production Environment – Each standard also defines a set of supporting system

software to provide needed services, such as maintaining component directories, enforcing security requirements, and encoding and decoding messages across networks and other transport protocols.

– The exact system software, its hardware, and its configuration requirements vary substantially among the component interaction standards.

Configuring the Production Environment

• Configuring the Production Environment – The diagram shows a typical support infrastructure for an

application deployed using Microsoft .NET, a variant of SOAP.

Configuring the Production Environment

• Configuring the Production Environment – Application software components written in such

programming languages as Visual Basic and C# are stored on one or more application servers.

Configuring the Production Environment

• Configuring the Production Environment – Other required services include • a Web server for browser-based

interfaces, • a database server to manage the

database, • an Active Directory server to

authenticate users and authorize access to information and software resources,

• a router and firewall, and • a server to operate such low-level

Internet services as domain naming system (DNS) and Internet address allocation (DHCP).

Configuring the Production Environment

• Configuring the Production Environment – Unless it already exists, all this hardware and system software

infrastructure must be acquired, installed, and configured before application software can be installed and tested.

– In most cases, some or all of the infrastructure will already exist—to support existing information systems. • In that case, developers work closely with personnel who

administer the existing infrastructure to plan the support for the new system.

– In either case, this deployment activity typically starts early in the project so software components can be developed, tested, and deployed as they are developed in later project iterations.

Summary

The main activities for deployment are • UAT • Converting and Initializing Data

– Reusing Existing Databases – Reloading Databases

• Training Users: End users and System operator – System documentation for System operator

» Descriptions of system requirements, architecture, and construction details

– User documentation. » Descriptions of how to interact with and use the system

• Configuring the Production Environment – Modern applications are built from software components based on

interaction standards. Each standard defines specific ways in which components locate and communicate with one another.

Read

Textbook:

• Satzinger, Robert & Stephen Chapter 14