The performance of an LCD monitor ultimately depends on how its liquid crystals are manipulated to channel light. We’ll examine the three most common technologies: Twisted Nematic (TN), In-plane Switching (IPS), and Vertical Alignment (VA).

Each of these three technologies creates a pixel using a cell of liquid-crystal molecules controlled by a thin-film transistor. Liquid crystals are used because they’re capable of effecting light as though they’re a solid, while exhibiting the malleability of a fluid. In a color LCD, each pixel is subdivided into three cells, or subpixels, which are colored red, green, and blue, respectively, by additional filters. These cells are arranged in a matrix of rows and columns sandwiched between two panes of glass, with a polarizing film on the exterior side of each pane.

A light source, such as a cold cathode fluorescent lamp or an LED grid, is placed behind the first glass panel. Light waves from the backlight follow the alignment of the liquid-crystal molecules, but they must pass through the two polarizing filters before reaching the surface of the display. Light waves must be oriented perfectly parallel to the first filter to pass, but since the second filter is oriented perpendicular to the first, no light will pass unless it’s reoriented first.

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Though solid state drives have existed for years, it is only recently that they’ve gained any sort of market penetration for average users. As we stated in our February 2009 white paper on the subject, solid state drives offer many advantages over traditional magnetic drives. Unlike mechanical hard drives, SSDs have no moving parts, so they draw less power and produce no vibrations. They’re also more resistant to physical shock. And most importantly, solid state drives offer much higher read and write speeds than traditional hard drives—at least when they’re new. Due to their NAND flash architecture, SSDs can suffer serious slowdowns once they run out of fresh blocks to write to. The TRIM command, found in Windows 7 and newer releases of the Linux kernel, aims to fix this. But what is TRIM, and why is it even necessary?

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Designing and manufacturing a modern CPU is a huge project. It requires both backward compatibility and an understanding of where PC workloads are going in the future—a delicate balancing act made more difficult by the huge engineering staffs and massive dollar outlays involved. Let’s take a look at the steps needed to build a Core i7 or AMD Phenom II processor.

Before the manufacturing plant starts churning out chips, there are a few critical preliminary steps. Prior to the first circuit being laid out or the first simulation run, the designers need to know exactly what it is they’re designing. This phase takes input from many sources. Marketing gets involved, with predictions of what users will need when the CPU actually ships, usually two to four years in the future. Engineering and performance teams feed in billions of traces of actual applications being run on current-gen CPUs, so the designers can see how existing CPUs perform under real-world conditions.

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When can a file encapsulate more than one type of data? When it’s a metafile, wrapper, or container file. You might think of a container file as a package or envelope in which other files are housed. Zip files, which can contain documents, photos, videos, software programs, and many other types of files, are one type of container that you encounter frequently.

We’ll limit our discussion here to media container formats. A pure container file specifies how the data is stored, but it doesn’t necessarily know how it was compressed or encoded or even what is required to play back those files. This can lead to confusion when dealing with container files wrapped around media because there’s a chance that the media player you’re using is capable of opening the container but not equipped with the algorithm required to decode the files inside. Although a container can theoretically hold any type of data, most are optimized during development to wrap around particular data groups, e.g., digital audio for music; static images for digital photographs; or digital video interleaved with digital audio, plus subtitles, closed-caption information, and chapter data for movies. Container formats that support video also include the information required to synchronize the various data streams in the file during playback.

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