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© 2003 Pluta Brothers Design, Inc. http://www.plutabrothers.com
Guest speaker:Joe Pluta, Pluta Brothers Design Inc.
© 2003 Pluta Brothers Design, Inc. http://www.plutabrothers.com
This is a review of the various technologies for Web-enabling legacy applications. Companies Web-enable for many different reasons, and there are many different options. Some of them you may not have even considered. So, rather than rehash just the most popular techniques, this presentation will attempt to address all of your Web-enabling options. I’ll also try to give you some idea of the available products.
© 2003 Pluta Brothers Design, Inc. http://www.plutabrothers.com
The Options
Replacing
Refacing
Rewriting
© 2003 Pluta Brothers Design, Inc. http://www.plutabrothers.com
Replacing
If your existing system is out of date and unable to cope with your requirements, you may want to consider replacing it.
Many vendors can supply you with ready-made Web-enabled systems.
© 2003 Pluta Brothers Design, Inc. http://www.plutabrothers.com
Refacing
Traditional Model
Terminal Emulation
Thin-Client Computing
Screen Scraping
© 2003 Pluta Brothers Design, Inc. http://www.plutabrothers.com
Traditional Model
RPG Program
Display File
5250 Terminal
5250 datastream
Workstation Data
ManagementEXFMT
© 2003 Pluta Brothers Design, Inc. http://www.plutabrothers.com
Terminal Emulation
RPG Program
Workstation Data
Management
5250 Emulator
Display File
EXFMT5250 datastream
© 2003 Pluta Brothers Design, Inc. http://www.plutabrothers.com
Terminal Emulation
Many vendorsClient Access ExpressMochasoftRumbaShareware and Freeware 5250 Emulators
© 2003 Pluta Brothers Design, Inc. http://www.plutabrothers.com
Terminal Emulation
Can now be done over VPNVirtual Private NetworkSecure, Stable, ReliableSpeed depends on Internet connection
© 2003 Pluta Brothers Design, Inc. http://www.plutabrothers.com
Thin Client Computing
RPG Program
Workstation Data
Management
5250 Emulator
Display File
EXFMT5250 datastream
Thin Client
TCP/IPThin-Client Terminal
Server
© 2003 Pluta Brothers Design, Inc. http://www.plutabrothers.com
Thin-Client Computing
Citrix MetaFrameGraphOn WinBridgeMicrosoft Terminal ServerSCO TarantellaVirtual Network ComputingWyse Winterm
© 2003 Pluta Brothers Design, Inc. http://www.plutabrothers.com
Screen Scrapers
RPG Program
Workstation Data
Management
Screen Scraper Client
Display File
EXFMT5250 datastream
© 2003 Pluta Brothers Design, Inc. http://www.plutabrothers.com
Screen Scrapers
Providers dwindling:Core TechnologyJacadaSeagullZephyr
Gone:EaselFlashpointMozart
© 2003 Pluta Brothers Design, Inc. http://www.plutabrothers.com
To Scrape or not to scrape
Pros:No source changesDesktop integration
Cons:Fewer vendorsThe interactive tax
© 2003 Pluta Brothers Design, Inc. http://www.plutabrothers.com
CFINT: The Interactive Tax
CFINT is a system job that consumes CPU resources when it recognizes that your interactive workload exceeds the interactive CPW rating of your machine. This governor is indiscriminate: When CFINT kicks in, all of your jobs, batch and interactive, come nearly to a standstill.
© 2003 Pluta Brothers Design, Inc. http://www.plutabrothers.com
CFINT: The Interactive Tax
Most new iSeries models now offer only two options for interactive CPW:
Standard models have zero interactive capability
Advanced edition servers have full interactive capabilities
Except for the very smallest iSeries model, there is no middle ground.
© 2003 Pluta Brothers Design, Inc. http://www.plutabrothers.com
How Much Does CFINT Cost?
To determine the direct cost of interactive CPW, go to the following IBM Web page:
http://www.iseries.ibm.com/servlet/factFind
This page compares the costs of various iSeries configurations.
© 2003 Pluta Brothers Design, Inc. http://www.plutabrothers.com
How Much Does CFINT Cost?
The 810-0869 is a 2700 CPW machine. With zero interactive this model costs $50,000, while the same machine with max interactive costs $245,000 – nearly five times the cost.
CFINT makes your hardware costs higher.
© 2003 Pluta Brothers Design, Inc. http://www.plutabrothers.com
IBM Options
Screen ScrapersHost PublisherHost On-DemandHATS
Like all screen scrapers, the IBM screen scraper solutions require interactive CPW.
© 2003 Pluta Brothers Design, Inc. http://www.plutabrothers.com
IBM Options
RPG Program
Workstation Data
Management
Display File
EXFMT
Java Beans and Java
ServerPages
Browser
HTML
WebFacing Runtime (WAS)
Data Buffers
© 2003 Pluta Brothers Design, Inc. http://www.plutabrothers.com
IBM Options
Until just recently, WebFacing also used interactive resources. Now, however, on the newer server models WebFacing will not require interactive CPW.
© 2003 Pluta Brothers Design, Inc. http://www.plutabrothers.com
Interactive Technologies
Except for the new WebFacing offering, these are all interactive techniques that require no modifications to the legacy systems. These have an initial cost/benefit advantage. However, the new IBM pricing model has made interactive solutions too expensive for many businesses to maintain.
© 2003 Pluta Brothers Design, Inc. http://www.plutabrothers.com
© 2003 Pluta Brothers Design, Inc. http://www.plutabrothers.com
Rewriting
© 2003 Pluta Brothers Design, Inc. http://www.plutabrothers.com
Rewriting
Two architectures:Client/Server
Application logic on client, makes requests to servers on the hostExamples: ODBC or Web services
Server/ClientApplication logic on server, makes requests to client to present dataExamples: X-Windows or good old 5250
© 2003 Pluta Brothers Design, Inc. http://www.plutabrothers.com
Client/Server
Business logic encapsulated in servers or replaced by ODBC callsApplication logic moves to clientThree client options:
Remote databaseThick clientBrowser-based
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Remote Database
AS/400DB2
ODBC Support
Workstation
ODBC based appli-cation
© 2003 Pluta Brothers Design, Inc. http://www.plutabrothers.com
Remote Database
Remote database designs are relatively less flexible than other architectures. Because the client must have complete knowledge of the database layout, changes to business rules that affect your database can be difficult to deploy.
Remote database is best suited for ad hoc user queries, and not for mission-critical enterprise applications.
© 2003 Pluta Brothers Design, Inc. http://www.plutabrothers.com
Thick Client
AS/400Program
Call Support
Workstation
Client/Server Appli-cation
Server
Server
Server
© 2003 Pluta Brothers Design, Inc. http://www.plutabrothers.com
Browser Based
AS/400 Workstation
Web browser
Web Application
Serverxxxx
xxxx
xxxx
Note: This interface uses only HTML, so no sophisticated graphics are supported.
Server
Server
Server
Application and
business logic
© 2003 Pluta Brothers Design, Inc. http://www.plutabrothers.com
Other
The other client/server architectures share the same concept: business logic is encapsulated in servers. Whether exposed via program call or Web service, or encapsulated in Java classes, these server programs are probably the ultimate goal of a complete rewrite.
© 2003 Pluta Brothers Design, Inc. http://www.plutabrothers.com
Other
Unfortunately, there are no tools today that can directly mine business logic, although some companies are beginning to claim that ability. Certain 4GL vendors also claim to be able to encapsulate your business rules. But in most cases, a true client/server design will require a significant investment in rewrite (which also means re-testing).
© 2003 Pluta Brothers Design, Inc. http://www.plutabrothers.com
Server/Client
Application logic unchangedI/O requests replaced by API callsThree UI options:
Thick client on workstationThick client appletCGI or servlet/JSP to browser
© 2003 Pluta Brothers Design, Inc. http://www.plutabrothers.com
Browser Technologies
Static Web pagesCommon Gateway InterfaceServletsJavaServer PagesJSP and servlets
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Static HTML
Workstation AS/400
Web Server
Web Browser
HTTP Request
HTML Data
Static HTML Pages
© 2003 Pluta Brothers Design, Inc. http://www.plutabrothers.com
Workstation AS/400
Web Server
Web Browser
HTTP Request
CGI Program(RPG, Perl, …)HTML
Data Database Data
Common Gateway Interface
© 2003 Pluta Brothers Design, Inc. http://www.plutabrothers.com
Workstation AS/400
Web Server
Web Browser
HTTP Request
Servlet(Java)HTML
Data Database Data
Servlet
© 2003 Pluta Brothers Design, Inc. http://www.plutabrothers.com
Workstation AS/400
Web Server
Web Browser
HTTP Request
JSP ProcessorHTML Data
Database Data
JavaServer Pages JavaBeans
JavaServer Pages
© 2003 Pluta Brothers Design, Inc. http://www.plutabrothers.com
Workstation AS/400
Web Server
Web Browser
HTTP Request
Servlet
HTML Data
Database Data
JavaServer Pages
JSP Processor
JavaBeans
Servlet/JSP
© 2003 Pluta Brothers Design, Inc. http://www.plutabrothers.com
Server/Client
Application logic unchangedI/O requests replaced by API callsThree UI options:
Thick client on workstationThick client appletCGI or servlet/JSP to browser
© 2003 Pluta Brothers Design, Inc. http://www.plutabrothers.com
Server/Client - CGI
AS/400 Workstation
Web browser
HTTP Server
Application rewritten to
replace workstation I/O with CGI calls.
xxxx
xxxx
xxxx
Note: This interface uses only HTML, so no sophisticated graphics are supported.
© 2003 Pluta Brothers Design, Inc. http://www.plutabrothers.com
Server/Client - CGI
Replace I/O with CGI callsRequires an HTTP serverSeveral vendors
FreeStyle/400LegacyWebRelational Web (*)
© 2003 Pluta Brothers Design, Inc. http://www.plutabrothers.com
Server/Client - Thick Client
AS/400Application
ClientServer Client APIs
Workstation
Thick Client
UI Server
© 2003 Pluta Brothers Design, Inc. http://www.plutabrothers.com
Server/Client – Thick Client
Replace I/O with server/client APIMay require additional software
JacadaPSC/400Seagull
© 2003 Pluta Brothers Design, Inc. http://www.plutabrothers.com
Server/Client - Applet
AS/400Application
ClientServer Client APIs
Workstation
Web browser
HTTP Server
UI Server Applet
© 2003 Pluta Brothers Design, Inc. http://www.plutabrothers.com
Server/Client - Servlet/JSP
AS/400Application
ClientServer Client APIs
Workstation
Web browser
Web Appl. Server
Servlet
Java Server Page
xxxx
xxxx
xxxx
Note: This interface uses only HTML, so no sophisticated graphics are supported.
© 2003 Pluta Brothers Design, Inc. http://www.plutabrothers.com
Server/Client – Servlet/JSP
Replace I/O with server/client APIRequires Web Application ServerMay require additional software
JacadaJaci/400PSC/400Seagull
© 2003 Pluta Brothers Design, Inc. http://www.plutabrothers.com
Server/Client – Servlet/JSP
© 2003 Pluta Brothers Design, Inc. http://www.plutabrothers.com
Server/Client – Servlet/JSP
© 2003 Pluta Brothers Design, Inc. http://www.plutabrothers.com
Server/Client – Servlet/JSP
© 2003 Pluta Brothers Design, Inc. http://www.plutabrothers.com
Dialup Batch Thick Client Browser No Source Time CostEmulation Y N N N Y - -Thin Client N N N (N) Y + ++Scrapers (N) N Y N Y ++ +++WebFacing (N) (Y) N Y (N) ++ -C/S Y Y Y Y N ++++ -S/C CGI Y Y N Y N +++ +S/C thick Y Y Y N (N) +++ ++S/C browser Y Y N Y (N) + +++
© 2003 Pluta Brothers Design, Inc. http://www.plutabrothers.com
Server/Client – Servlet/JSP
© 2003 Pluta Brothers Design, Inc. http://www.plutabrothers.com
Server/Client – Servlet/JSP