Technical information

Reviewer’s Guide Microsoft Windows NT Workstation 3.51 8
• Windows NT Workstation requires considerably less memory in order to run efficiently, and consequently
provides higher performance. One internal test scenario demonstrates this improved performance relative to
Windows NT 3.1. the test shows the amount of time it took to complete the tests on Windows NT 3.1
compared with Windows NT Workstation, while holding the memory constant. To summarize, a system
with Windows NT Workstation and 12 MB of memory ran as efficiently as a system with 24 MB of
memory under Windows NT 3.1. A Windows NT Workstation system with 16 MB of memory is faster than
a Windows NT 3.1 system with 32 MB.
• Improved 16-bit application performance. On desktop systems with comparable configurations, Windows
NT Workstation appears to be 25-50% faster than Windows NT 3.1 using the same test scenarios
2
.
Graphics performance has improved by 200% over Windows NT 3.1.
• Improved 16-bit application performance on systems with RISC CPUs. For RISC systems, such as those
based on the Alpha AXP and MIPS microprocessors, the underlying Intel emulation for 16-bit applications
for Windows and MS-DOS operating systems has been greatly improved resulting in major improvements
in the performance of these applications.
These tests don’t measure some of the other architectural improvements to Windows NT Workstation that can
favorably affect system performance. For example, with support for multiple virtual DOS machines (MVDMs), 16-
bit applications can be effectively multitasked. Each 16-bit application inhabits its own separate process space. By
ensuring that some tasks run in the background, this multitasking results in an increase in overall system performance
as perceived by the user.
The combination of performance improvements and decreases in hardware pricing makes Windows NT Workstation
even more cost-effective to deploy as an operating system.
Multiple VDM Support
One of the most important features included in Windows NT Workstation is the ability for 16-bit Windows-based
applications to run in multiple Virtual DOS Machines (VDMs) while retaining all of the application integration
capabilities, such as DDE (Dynamic Data Exchange) and OLE (Object Linking and Embedding).
In Windows NT 3.1, the 16-bit Windows environment was defined to be a shared memory system, that is, all 16-bit
applications for Windows would share the memory within a single VDM. Using shared memory became a common
way for applications to pass information between each other and, consequently, become more tightly integrated.
This enabled personal productivity applications to take advantage of key integration capabilities that are supported
by Windows, including DDE and OLE.
However, a negative side effect of this arrangement was that the 16-bit Windows environment was only as reliable as
the least reliable application that was installed. If an application did not completely follow the Windows
programming model, then it could cause a general protection fault in the 16-bit Windows environment. This could
bring the entire 16-bit environment to a halt, causing the loss of all of the user’s data.
With Windows NT Workstation, applications can now be configured to run in their own 16-bit environment. The
configuration for this option is shown in the picture on the following page. Within Windows NT Workstation, each
16-bit VDM is defined as a separate process. This feature improves the overall reliability of the system since, now, if
one application fails, it does not affect the remaining 16-bit applications that may be running. IBM has referred to
this kind of capability as “crash-protection.”
2
The Microsoft Internal Tests and WinBench tests were conducted on a 486/66 system with 16MB of memory.