1. What is a Netbook?
Because of its swift adoption, the term “netbook” drew more than 35 million hits on Google without a universally recognized definition. In addition, PC manufacturers are still changing the features of netbooks in an attempt to capture more market share and outsmart the competition. There is, however, a somewhat generally accepted description of a netbook.
Netbooks are defined as much by their features as their lack thereof. Most netbooks offer an 8 to 10 in. screen, an Atom x86 processor, Windows XP or Linux OS, wireless networking, and USB connectivity. All of these features are presented in a small package weighing less than 3 lb and consuming an average of 15 W of power. Most netbooks do not have optical drives, full-sized keyboards, HDMI connectivity, or the ability to run processor-intensive applications. These characteristics allow the vast majority of netbooks to be priced at less than $400 USD.
The innovative Atom processor provides respectable computing power that can be used for more than simple Web browsing.
Table 1. Feature Comparison for Typical Computing Devices
In a reversal of the “bigger is better” era, netbooks provide a radically different approach to computing by adeptly addressing 80 percent of standard laptop use cases at an affordable price. They are not intended for 3D animations or video editing, but they are well-suited for most day-to-day applications such as Web browsing and word processing. Most customers purchase netbooks as secondary or tertiary computing devices to perform simple day-to-day leisure computing away from their desktops.
2. New Virtual Instrumentation Platform
Data acquisition and measurements evolved greatly since the early days of large, single-function desktop boxes. Virtual Instrumentation, the concept of PC-based instruments and measurements, has since been embraced by engineers and scientists, providing a software-defined approach to measurement, test and automation.
Figure 1. NI bus-powered USB data acquisition products work well with netbooks because
they offer high-performance I/O in a small, portable, bus-powered form factor.
The advent of netbooks introduced a lower-cost, more portable computing platform for virtual instrumentation that is capable of performing user-defined measurements and analysis without compromising connectivity and storage. National Instruments bus-powered USB data acquisition products are the ideal match for netbooks because they offer high-performance I/O in a small, portable, bus-powered form factor.
3. Hardware Considerations
Figure 2. System Diagram of a Netbook-Based Measurement System
At the core of a netbook is a low-power processor. Most netbooks are equipped with the Intel Atom, a new processor designed for low-power computing applications based on the widely adopted x86 instruction set. The 2.5 W maximum CPU is capable of running at up to 1.6 GHz. The complete chipset for the Atom processor, which includes the graphics processing unit (GPU), north bridge, and south bridge, consumes a maximum of 11.8 W total, a very small number compared to a typical Core Duo notebook processor, which requires up to 30 W.
Atom processors also support hyperthreading, a proprietary technology from Intel used to process two threads simultaneously on a single core with unused resources. It does not provide true parallelism like dual-core processors, but it does deliver significant performance improvements for multithreaded applications. Benchmarks for single-threaded, 1024-sample fast Fourier transforms (FFTs) were at around 8 kFFT/s, while running two threads increased the performance to more than 12 kFFT/s.
Figure 3. Benchmark Chart Comparing FFT Performance
Overall, netbooks deliver enough processing power for most measurement and data-logging applications. However, they are not suited for analysis-intensive applications or applications where low latencies are a requirement.
The first thing most users notice when examining a netbook is its size. Typically weighing less than 3 lb, netbooks are among the smallest and lightest x86 computing devices on the market. Its low power consumption enables smaller batteries without compromising its overall battery life.
The 8 or 10 in. screen size makes for a compact shape but poses challenges in usability, with most Web site widths barely fitting in the WSVGA screen resolution of 1024x600. It also requires more scrolling because of its short view. This is especially noticeable when viewing large amounts of data or programming in either text-based or graphical programming environments.
Netbooks can provide plenty of disk storage, especially when equipped with a rotating hard-disk drive (HDD). Solid-state drives, or SSDs, are more energy-efficient, but they do not offer as much storage and can cost substantially more. An SSD-equipped netbook typically features only 8 GB of storage.
Note that not all SSDs are created equal; the flash memory contained in an SSD has a limited amount of reads/writes. Wear leveling, a way to distribute reads and writes evenly across all sectors of the drive through various algorithms, helps increase the lifespan of the drive. However, these wear-leveling algorithms vary between manufacturers and drives. Thus the perception of SSDs lasting much longer than HDDs due to their lack of moving parts is not always true, so be careful when selecting an SSD.
Because of the Atom’s 945 chipset, most standard connectivity options are available, including Ethernet, USB, 802.11g, and ExpressCard. These standard ports provide access to a wide variety of data acquisition devices and multiple methods of transferring measurement data.
Benchmarks for the netbook USB port show performance levels sufficient for most NI USB data acquisition (DAQ) devices. However, netbooks are not suitable for use with NI CompactDAQ and NI USB-625x high-speed M Series multifunction DAQ modules when running all analog and digital I/O tasks at high rates.
Figure 4. Benchmark Chart Comparing USB Throughput
4. Software Considerations
The adoption of the Linux OS with netbooks has increased partially because of higher Microsoft Windows OS licensing fees. Linux-based OSs such as Ubuntu support Web browsing and most Web-based applications. However, Linux-based netbooks do not offer strong third-party software support, and Linux distribution-specific hardware drivers are hard to find. These limitations confine Linux-based netbooks to mostly Web browsing and basic computing.
Windows XP-based netbooks offer sufficient performance at a slightly higher price than Linux-based netbooks while still costing less than $400 USD. And because Windows OSs are the most widely supported OSs in the data acquisition space, it makes sense for developers and engineers to favor Windows-based netbooks for their applications.
Any software running on a netbook needs to work well with its small screen size and reduced computing power. The software user interface (UI) becomes highly important on such a small device, which requires an environment featuring flexible UI tools with a large library of customizable objects. In addition, because of the availability of hyperthreading on Atom processors, developing a multithreaded application is also useful and can provide an up to 50 percent increase in computing performance.
Microsoft Visual Studio .NET features a basic set of UI tools; however, these tools are often insufficient for most data acquisition applications. In addition, developing multithreaded applications in Visual Studio .NET is a manual and difficult process, and the software lacks advanced signal processing tools.
Table 2. Comparison of Development Environments for Measurement Applications
NI LabVIEW, a graphical programming environment, provides a wide array of objects to help engineers and scientists design custom UIs and maximize the screen space of a netbook. In addition, the LabVIEW dataflow programming paradigm removes most of the challenges associated with managing pointers and data types in text-based languages. And because it is inherently multithreaded, LabVIEW automatically takes advantage of hyperthreading on the Atom processor. Learn more about LabVIEW at ni.com/labview.
For quick, simple measurements, NI offers LabVIEW SignalExpress configuration-based measurement software with all NI data acquisition hardware. LabVIEW SignalExpress is designed for quickly measuring, analyzing, and presenting data, with no programming required.
Choosing high-performance, easy-to-use driver software is just as important as selecting the appropriate development environment. Most data acquisition device drivers on the market provide only basic functionality and operate on a single thread.
NI-DAQmx, the National Instruments flagship data acquisition driver software, is natively multithreaded and features a variety of deployment options, which helps reduce footprint to less than 180 MB. This enables NI to offer a full-featured, time-saving hardware driver for netbook-based data acquisition application development while providing only a slimmed-down run-time driver for the final deployed application. Because netbook storage can be as low as 8 GB, every megabyte counts.
Data management is an important aspect of data acquisition. Because netbooks are typically used as secondary or tertiary computing devices, it is often necessary to move data back and forth between the netbook and a higher-performance PC. This can be difficult, depending on the development environment and software tools available.
At the most basic level, files such as .cvs and .txt are easily accessible through most common word processing and spreadsheet software for small data sets and simple visualization. However, these are not optimized for large data sets, rapid data mining, and high-throughput applications.
For data acquisition, National Instruments has created a flexible technical data management (TDM) model called NI TDM. The structured, search-ready NI TDM file format uses an XML header to manage a wide range of attributes associated with each data file. It is designed to capture and manage all of the important information for a measurement or simulation, ensuring that the data is reliably stored and reusable and that it requires no additional work to recreate the conditions in which it was captured.
Technical data management streaming (TDMS), a variation of TDM, provides the best performance available. This file format streams binary data and header information to disk, bypassing operating system overhead that would otherwise lower the throughput and increase the latency of the data streams.
Netbooks are effective for the aforementioned applications including data logging, simple signal analysis, and mobile measurements. And for low-cost, portable applications requiring more advanced signal processing, netbooks can offload demanding computing algorithms to standard desktops and/or large servers. When the above considerations are examined thoroughly, netbooks can significantly lower the cost of a measurement system in a highly portable form factor.
Data Acquisition Product Manager
1 ABI Research (January 26, 2009), 35 Million Netbook Shipments Expected in 2009: An Era Begins. Press release, Retrieved on 05/11/2009
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