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Test & Measurement World: Windows 7 for test applications

A recent discussion on a LabView user group revealed that engineers are starting to use Windows 7 for controlling instruments. Many automated measurement systems, however, will continue to run Windows XP or perhaps an older version of Windows for as long as the systems are useful. Other systems may get Windows 7, but not until the system computer needs to be replaced. The exceptions might be systems with Vista computers, which are likely to get Windows 7 upgrades.

If you upgrade to Windows 7 with a new PC, you’ll likely find more differences in the computer than just those that Windows imposes, especially if you use PC-plug-in instrument cards. For example, you may find that you no longer have enough PCI slots. Instead, you may find PCIe (PCI Express) slots. That could force you to buy new instrument cards, which might improve throughput.

If you replace your PCI cards with PCIe cards, you’ll have to consider moving to the 64-bit version or staying with 32 bits. In high-speed or highchannel- count applications where you might collect lots of data, you can benefit from a 64-bit operating system, because it breaks the 4-Gbyte memory ceiling.

But Sean Sullivan, director of engineering at Data Translation, said, “Running 32-bit applications on Win64 might actually be slower than running them on a 32-bit version because all calls go through the WOW64 [Windows on Windows 64-bit] layer. The best scenario is to run 64-bit applications with your 64-bit drivers, but it is going to take some time before applications are available in 64-bit versions.”

In addition, moving to the 64-bit Windows 7 might put your 32-bit applications at risk. Armando Valim, LabView product manager at National Instruments, noted that older 32-bit applications may not work on Windows 7 due to compatibility issues.

Several companies have announced support for 64-bit Windows 7. National Instruments currently supports 64 bits for many of its products. Agilent Technologies has announced 64-bit driver support for its Acqiris line of digitizer cards. Other companies with 64-bit drivers for instrumentation cards include Adlink, Measurement Computing, and ZTec Instruments.

Valim explained that NI has a team of engineers running benchmark tests on Windows 7 to compare it to Vista and XP. He said that with Windows 7, you should see a slight improvement —up to 10%—in multicore applications and that Microsoft has improved its USB support by up to 20%.

If you’re thinking about using a Windows 7-based notebook computer, you should be aware of changes in power management. Valim pointed out that Windows 7 is more aggressive with its power management than previous Windows products. “Windows 7 goes into power-save mode too quickly for many measurement applications,” he said. “You may need to change the power-management settings to keep the measurements coming.”