| Microsoft Year 2000 Readiness Disclosure
and Resource Center |
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| Integrate the Enterprise |
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4.
Technology Overview
These
are the specific technologies and products that are essential for
successfully integrating client/server, intranet and Internet
applications with legacy systems.
Terminal emulation software provides the means for a
client to interact with a host like it is a terminal. The
application is displayed the way it looks on an IBM 3270 terminal
screen, with some of the advantages of graphical user interface,
such as windowing, screen print, and other basic services.
Scripting languages offer developers more control
over a client running in terminal emulation mode. This includes
receiving return codes and downloading files from the host to the
client.
Screen scraping is the next integration level and can
be used by a development team to create a graphical front end using
either a rapid application development (RAD) environment or a more
traditional language such as C++. Functionality can be split easily
between the client and the host, while providing easier use and new
capabilities, such as images and scrollable lists, and the security
of host-based data. There is also a new category of screen scraping
technologies in which a browser can be used to interact with a host.
Object interfaces are used by programmers to execute
high-level services on a client to reach legacy data.
Object-oriented interfaces predominately support Microsoft VBX and
OCX conventions; these object extensions are based on Microsoft
Visual Basic« or ActiveXÖ technologies. One of the most popular
application program interfaces (API) that can be accessed easily by
an application developer is Open Database Connectivity (ODBC), an
API that is layered over communications protocols to create links to
legacy databases, such as DB2.
Systems Network Architecture (SNA) is the foundation
for efficiently integrating legacy applications and data with modern
network systems and applications, to give users convenient, reliable
access to host systems. Microsoft SNA Server 3.0 is one of the
leading SNA gateways.
VSAM file access will be easier with a new,
forthcoming component of SNA Server, currently code-named "Thor."
"Thor" allows VSAM access from COM-based clients. It is designed to
provide customers with tools to easily and efficiently integrate
mainframe VSAM and AS/400 data sources with other enterprise-wide
data sources using a common methodùOLE DB.
Program-to-program interoperability and complex
distributed processing becomes practical with a technology currently
code-named "Cedar." "Cedar" is a Microsoft project that will provide
a bridge between distributed clients and mainframe-based
applications. Developers can now build powerful new applications
using the Microsoft Active Server to leverage existing mainframe
logic and associated data without making system changes to the host
or calling APIs on the client. This is possible because "Cedar" is
executed from a middle-tier Windows NT Server computer.
DCOM for MVS, ported by Software AG. Based on the
Windows NT source code, Software AG has released DCOM on Unix
(Solaris) and most recently MVS, with plans for other platforms,
including the AS/400 and other versions of UNIX. Using DCOM:
- Components written in different languages communicate
across the most broadly used client and server platforms.
- Developers can create binary components that inter-operate
with other binary components built by different developers.
Accessing host data and applications can be
implemented easily with Microsoft Internet Explorer with ActiveX
Controls for host access, screen scrapping and data publishing.Using Microsoft Internet Explorer and ActiveX,
corporate users can now "surf" their environments, tapping the new
role of the mainframeùor AS/400 or other mid-range systemsùas an
Internet/intranet server. The ActiveX Controls to accomplish this
are available from Wall Data Systems and Attachmate Corporation. In
addition, Wall Data offers Arpeggio to provide
information publishing as well as advanced screen scrapping of host
applications. In each case, all the complexities of enterprise
information and application access are handled in the ActiveX
Controls.
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