Availability Guide for Application Design

Designing Applications for Change
Availability Guide for Application Design—525637-004
10-14
Considering Portability Requirements
The NonStop operating system platform contributes scalability and portability to the
Windows NT Server platform in the following key ways:
•
HP contributes substantial technology derived from the NonStop operating system
to the Microsoft Server Cluster Server (MSCS). This technology is part of the
standard MSCS product and delivered with the Windows NT Server product from
Microsoft.
•
HP ports to the Windows NT Server platform middleware products and associated
enabling technology available on the NonStop operating system. This enables the
rapid development of applications capable of exploiting and extending the MSCS
clustering capabilities without direct exposure of the applications to the MSCS
APIs.
HP selected the most open of the NonStop operating system transactional products,
NonStop SQL/MP and NonStop Tuxedo, and ported those products to Windows NT
Server to form the common NonStop Software product set. To support those products
in exploiting the inherent parallelism and availability of the clustered Windows NT
Server architecture, the key NonStop operating system features of TMF and NonStop
TS/MP have been ported to the Windows NT Server platform as the Transaction
Manager and Transaction Distributor, respectively.
These middleware products are designed to be open and so provide compatibility not
only with the NonStop operating system, but also with the cluster-unaware versions of
enablers available from other suppliers of uniprocessor or SMP systems on Windows
NT Server or other platforms.
The NonStop Software presents a great opportunity for complementary NonStop
operating system and Windows NT Server usage. For example, you can develop
applications on the NonStop operating system using the common middleware
products, knowing that those applications will port easily to future large-scale Windows
NT Server systems. It is also possible to develop applications using middleware from
other vendors, with the knowledge that those applications will port easily to the
NonStop operating system environment should requirements of availability or
scalability increase beyond the capabilities of Windows NT Server.
Easier Targeting of NonStop Operating System and Windows NT Server
Platforms
By combining carefully chosen APIs with isolation through library structuring or
conditional compilation, developers can target both the NonStop operating system and
Windows NT Server releases of the NonStop Software from a single workstation-based
development environment.
A single development environment for both platforms confronts minor incompatibilities
that might need to be addressed by the process adopted. One such engineering
consideration is the different library binding modes available on other platforms.
Prior to the introduction of native mode architecture and compiler products, user library
code on the NonStop operating system could not retain any data and required all
context data to be passed from the caller on each call. Native mode applications can