Maximum PC 2007 RSS Feed

White Paper: Touch-Screen Technology

Will Smith — Tue, 26 Feb 2008 11:58:31 -0600

Touch screens may never replace our clicky-clacky QWERTY keyboards—no, we’ll have to wait for brain-stem probes for that—but they are becoming more common. In fact, devices using this technology have been in use for more than 35 years and are becoming ubiquitous—kiosks, tablet PCs, desktop computers, and many handheld devices all now rely on human touch.

While the end result is the same—a display surface maps the coordinates of an input—touch screens rely on different phenomena to perform their functions, ranging from electrical current to infrared light to sound waves.

Resistive vs. Capacitive

A resistive touch screen sandwiches several thin, transparent layers of material over an LCD or CRT. The bottom layer transmits a small electrical current along an X and Y path. Sensors monitor these voltage streams, waiting for an interruption. When the flexible top layer is pressed, the two layers connect to form a new circuit. Sensors measure the change in voltage, triangulating the position to X and Y coordinates.

Resistive touch screens work with any kind of input, including a stylus or finger, and they’re usually very inexpensive to manufacture. They’re less durable than other types of touch screens, however, because the topmost layer experiences a great deal of wear from physical contact and constant flexing. Longevity isn’t a big problem for tablet PC and PDA deployments—two of the most common applications for resistive technology—but it can be for public kiosks, which are expected to endure more than 35 million impacts over their lifetimes.

Capacitive screens move the electrical layer to the top of the display. A minimal current is broadcast and measured from the corners of the monitor. When a person touches the screen, a small amount of the current is drawn away by the body’s natural capacitance. The sensors measure the relative loss of the current and a microcontroller triangulates the point where the finger made contact.

Capacitive screens are more durable than resistive screens because their top layers are fabricated from rigid glass. They are typically easier to read because thin layers of material aren’t on top of the display surface. The need for a live fingertip, however, often makes them feel less accurate to the end user than a stylus-driven interface. Trackpads and handheld devices, such as Apple’s iPod Touch and iPhone, commonly use capacitive input.

Surface Acoustic Wave

Surface acoustic wave (SAW) screens use beams of ultrasonic waves to form a grid over the surface of a display. Sensors along the X and Y axes monitor the waves; when one is broken, the X and Y points are combined to identify the touch coordinate.

SAW screens, like their capacitive counterparts, are durable and provide a clear line of sight to the display image, but the former work with any kind of input, be it a fingertip, a fingernail, or a stylus. On the other hand, they’re more susceptible to interference from dirt and other foreign objects that accumulate on the screen, registering surface contaminants as points of contact.

Infrared and Infrared Imaging

Infrared touch screens are similar to SAW screens in that they use a ring of sensors and receivers to form an X/Y grid over a display. But instead of sending electrical current or sound waves across this grid, infrared LEDs shoot invisible beams over the surface of the display. The microcontroller simply calculates which X and Y lines were broken to determine the point of input.

A frame around the display houses LEDs and photoreceptors on opposite sides. The LEDs emit light, which is detected by the photoreceptors. The display identifies X and Y coordinates when the user’s fingertip blocks one or more of the beams.

These screens work with a stylus, finger, or other pointer and give an unobstructed view of the display. They’re also durable because the point of input is registered just above the glass screen; only incidental contact is needed. Military applications often use infrared screens because of the product’s longevity.

Infrared imaging touch screens are vastly different from touch screens that use traditional infrared input. IR imaging screens use two or more embedded cameras to visually monitor the screen’s surface. IR beams are transmitted away from the cameras, illuminating the outside layer of the display. When the beams are disrupted by a fingertip or a stylus, the cameras measure the angle of the object’s shadow and its distance from the camera to triangulate the disruption.

IR imaging allows a direct view of the display. And since the input is registered just above the glass, physical contact is not required to initiate action. HP’s TouchSmart IQ770, one of the first mass-market touch-screen computers designed for the home, features this technology. HP markets the TouchSmart as an in-home kiosk that families can use for quick tasks without necessarily having to rely on the mouse and keyboard for navigation.

Acoustic Phase

While all the other touch-screen technologies rely on transmitting a wave or current, acoustic pulse screens just listen, literally. Two or more receivers are mounted at the edges of the screen to monitor contact. The tap of a finger, stylus, or other pointer makes a small sound vibration, which the display then triangulates. Based on the relative volume of the sound and other factors, the display can quickly determine where on the surface the input occurred. These types of touch screens are particularly useful in public kiosks, not because they’re impervious to surface scratches, but because the scratches don’t interfere with the screen’s ability to detect contact.

Touch the Future

Capacitive and resistive touch screens will likely continue to be the most commonly implemented technologies because of their low cost. They can even be combined into a single display, producing ideal fingertip or stylus input depending on the situation. However, we expect optical tracking to become more common because of its accuracy and flexibility.

Microsoft’s newly released Surface PC hides IR cameras beneath a tabletop screen. These cameras work similarly to IR imaging systems, but they monitor display interactions from below instead of from the side. This perspective allows the computer to visually identify input, offering a different interface depending on what is placed on the screen.

Surface, and other new displays are also embracing multitouch input. (The iPhone brought multitouch to the masses, although the technology has existed for 25 years.) Since the Surface PC can identify multiple fingers, it can let more than one user operate it at a time. Or single users can use multi-finger gestures to resize and manipulate items on the screen.

Nearly any of the touch-screen technologies can use multitouch input; however, some need additional sensors to help triangulate simultaneous inputs. The iPhone and the iPod Touch, for example, use a capacitive touch screen with coordinate-based inputs versus axis-based inputs. This allows two touches along the same axis—which would cause problems with certain capacitance touch-screen designs—to be registered as independent points of contact.

While the technologies may differ, we look forward to touch screens filling up walls and tables in our homes and offices. At that point, simple, direct interaction will beat traditional input methods. Who wants to carry a mouse around the house when a personal touch will do?

Beefing up Socket 939, RAIDing Heaven, SLI problems, and mobo upgrades.

The Maximum PC Staff — Fri, 08 Feb 2008 18:42:52 -0600

Beefing up Socket 939

Vista is telling me that my PC’s performance is bottlenecked at the CPU. I have top-of-the-line graphics with plenty of RAM and an AMD Socket 939 mobo with an FX-57 processor. I’ve looked at dual cores for my 939, but each core seems to be clocked lower than my FX-57, and I’m more interested in gaming than multitasking. With this in mind, could you tell me the best processor to put into Socket 939? I’d like this rig to last me at least another year or so.

—Blake Ogle

Microsoft Vista’s performance scores look to the future, so they tend to skew in favor of dual- and multicore machines. Regardless of these scores, your 2.8GHz FX-57 is indeed the highest-clocked 939 chip. The problem? It’s single core. A dual-core 2.6GHz FX-60 will still school it in most newer applications that support multithreading, and you’ll likely be able to overclock the processor to 2.8GHz without problems.

The bad news is that FX-60s are pricey and difficult to find. If you want to go dual core, the cheap route is the Opteron 185—a Socket 939 2.6GHz Opteron with 1MB of L2 per core. It’s basically an FX-60 without the FX. The main difference between the Opteron and the FX-60 is the level of multiplier locking—the former sticks you at 13x—and the reported lower thermals of the Opteron.

If you really want to future-proof your rig, you’re best off saving your cash and investing in a sleek, new quad-core CPU. With more and more games promising multicore support, sinking your cash into a quad-core processor would be the best way to maximize the life span of your rig. Of course, that would entail purchasing a new AM2-based motherboard, as you won’t be seeing any quad cores on 939 architecture.

RAIDing the Pearly Gates

I am a Roman Catholic priest, and I maintain a network of about 20 computers at the mission here. I want to have a RAID 1 array to boot from and a RAID 1 array for data. I don’t want these four hard drives striped to each other in any way.

I want the boot drive protected by a mirrored array so that if one drive fails, the second can take over. I want the data stored in a mirrored array of drives for the same reason. One of those two mirrored data drives would be removable. Can what I want be done?

—FronW

What you ask for might be possible, depending on the RAID implementation on the card or motherboard. On an Nvidia nForce 680, for example, you can build two separate RAID 1 arrays using four drives. The RAID controller will identify each drive that you add to an array.

Your plan to swap out the drives could work, but it’s hardly an ideal backup scheme since a mirrored RAID should never be considered synonymous with a system backup. Remember, a mirrored array creates two duplicate hard drives in every sense of the word: If a virus hits your system, that virus will exist on both drives in your array. The same holds true if you accidentally delete a file.

If one drive in a mirrored array fails, you just have to replace it with another drive and the array will rebuild itself back up to a two-drive protected entity. While that’s happening, the odds of the single healthy drive failing are rather low. But if you’re truly worried, you might want to lump all of your drives into a single RAID 6 array. That way, any two drives can fail and you’ll still have a working system and all of your data intact.

Struggling with SLI

How do you go about updating SLI videocard drivers? I have two GeForce 7950 videocards in SLI mode. I have refrained from updating the drivers until I first get some advice. What I think you have to do is uninstall the drivers from both cards and then install the drivers one at a time with reboots and then tell the cards to rebuild the SLI with one the master and one the slave? Is this correct?

—Rob Carver

Updating an SLI configuration is exactly the same as updating drivers on a single videocard. The Doctor suggests you first reboot your rig into safe mode and uninstall your videocards’ current drivers. To do that, pull up the Windows device manager, expand the Display Adapters menu, right-click each card, and select Uninstall. Next, restart your computer.

After you uninstall your videocard drivers, your computer will default to a generic VGA mode, which looks like this: ugly and huge.

Your screen will probably look a bit wonky or Windows may try to find and reinstall your card’s drivers. Don’t let it. Grab the latest 7950 drivers from Nvidia.com and double-click the executable to install them. Allow the program to restart your computer. When your OS reemerges, you might have to set your display resolution back to its normal setting, and you’ll surely have to re-enable SLI for your videocards in the Nvidia control panel. But you’ll now be running the latest drivers, and happiness will ensue.

Go, Go Mobo! Go!

I own a Compaq Presario desktop with an AMD Sempron 3400+ CPU. I want to upgrade to an Athlon 64 X2 CPU, but I first need to upgrade my motherboard. Will replacing the mobo nuke the factory-installed copy of Windows XP?

—Dylan Winn

Replacing a motherboard will do nothing to the contents of your hard drive—where Windows XP is installed. You could throw your motherboard off a balcony, buy a new motherboard of the same variety, put your computer back together, and everything would be peachy keen.

That said, when you replace your motherboard, you’ll want to reinstall XP. In fact, it’s not really a “you’ll want to” issue so much as it is a “Windows won’t boot” issue. So before your machine is in pieces on the floor, don’t forget to back up your important data!

Doctor. From Maximum PC, sweet Doctor. Would you please hang out with me? He works across the street up on the third floor of the Shoreline building. I saw him in his Lab, practicing his fixes. I knew you might just send him a computer question to doctor@maximumpc.com. Doctor. From Maximum PC… he’s the Doctor extreme!

How To: Benchmark Your PC without Breaking the Bank

David Murphy — Fri, 08 Feb 2008 18:12:56 -0600

We run benchmarks at Maximum PC because we have to; there’s no other way to determine the minute differences between systems without a repeatable standard of comparison. But you don’t have to be a reviewer to run a benchmark; in fact, regular benchmarking can give you valuable insight into the status of your system. For example, benchmarks are the best way to decipher whether the various performance-enhancing applications you’re running on your PC actually do anything or whether that latest batch of drivers hurt your gaming performance more than it helped.

The Maximum PC suite of benchmarks costs upwards of $1,000—a bit out of the price range of users who just want to see if their machines are up to snuff. But there are cheaper (and by that we mean free!) alternatives; we’ll show you how you can use them to test your rig in the comfort of your own home.

Time: 22 hours

What You Need

A PC
Cinebench
www.maxon.net
3DMark05
www.futuremark.com
Call of Juarez DirectX 10 Demo
http://tinyurl.com/2g6dhr
HD Tach
www.simplisoftware.com
Cosbi OpenSourceMark
www.sourceforge.net/projects/opensourcemark
Prime95
www.mersenne.org
Patience

Score Your CPU

We scoured the Internet and racked our brains to find the most appropriate (and most free) CPU test for your machine. And trust us, it wasn’t easy. Whittling down the list of options to just those that are free was difficult enough—there’s not much out there that will cost you absolutely nothing.

After picking through that small pile of programs, we discovered an important corollary that bears repeating: Just because a program claims to be a CPU test doesn’t necessarily mean the score it generates is a proper reflection of your CPU’s performance, particularly if you’re running a multicore machine. (Single-core users have a bit more leeway with their CPU benchmark choices, as anything that taxes the CPU is going to hit your one, lonely core.) The surest way to test a benchmark’s effectiveness is to pull up the Windows task manager while running a given CPU analyzer. A true CPU test will completely maximize the usage of all your cores.

Cinebench’s built-in database keeps track of all of your benchmark runs. Label everything correctly so you don’t forget what changes you’re testing!

Grab Cinebench and you’ll be pleasantly delighted by its absurd ease of use and applicable testing environment. The program runs on everything from single-core to 16-core machines. It’s a wonderfully future-proof little benchmark that gives you an overall performance score based on your computer’s ability to render a 3D image in as little time as possible. You can even record your results to a built-in database, a helpful way to keep track of your scores when modifying your rig. If you’re suffering any CPU performance loss as a result of your tweaking, Cinebench will let you know.

Test Your DirectX 9 Performance

One of the surest ways to test your videocard’s DirectX 9 performance is to—you guessed it—fire up a graphics-heavy game that includes a benchmark mode (like the FEAR benchmark we use in our Lab) and let ’er rip. But not every game tests your graphics card’s performance. There’s a reason we use Quake 4 and FEAR for our official benchmark runs: The former is an OpenGL-based game that’s far more dependent on your CPU than your videocard, whereas the latter is a better demonstration of GPU-based prowess.

If you have no acceptable games to test your rig’s performance, the next best thing is a free solution from Futuremark. Head over to the site and grab yourself the demo of 3DMark05. You might be tempted to download a later version for upgradeability’s sake—don’t. We’ve found that 3DMark05 pushes your graphics card more than later versions, which test the CPU a bit more.

The 3DMark05 official score throws your CPU into the mix, but you can get adequate FPS results from the app’s graphics-only tests.

Since the program’s a demo, you won’t get to edit any settings—you can’t adjust antialiasing, the resolution, or anything else. However, 3DMark05 will scale depending on the power of your graphics card, and there are numerous websites and forums you can visit to compare your demo score to the scores other rigs achieve!

Test Your DirectX 10 Performance

So you’ve plunked down big bucks for that fancy DirectX 10 card and you’re curious whether all the different drivers, tweaks, and overclocks have had any effect. The best free benchmark we’ve found is a DirectX 10 demo from Call of Juarez. It runs through a series of in-engine settings that test everything from particle effects to HDR antialiasing to shadows.

To squeeze more frames out of your DX10 card, reduce antialiasing. Your images will get a little jaggier, but you’ll see frame rates rise.

As with any benchmark, you’ll want to run multiple iterations of the graphical test to account for any errors or extraneous factors during the run. That said, the scores should be consistent, if not identical, across all three runs. If they aren’t, double-check to see if there’s anything eating up your computer’s resources in the background!

Benchmark Your Hard Drive

If you’re looking for the source of slowdowns in your system’s storage performance, the free HD Tach benchmarking utility is a must-have. With one click of a button, the application tests burst speeds, CPU utilization, random access speeds, and sequential read speeds.

The program gives you a ton of numbers once it’s finished. The most important of these is the average read speed of your drive—it takes less time to pull data from the inside layer of a platter than the outer, hence the “average” in the calculation. On the whole, this number is a good measure of your drive’s general performance.

If you have two identical hard drives in your PC, a large disparity in benchmark results could indicate a faulty drive. Back up now!

HD Tach’s burst speed measurement represents your drive’s ability to transfer data from its onboard cache to your CPU. Higher numbers indicate faster file transfers. The random access measurement indicates the time it takes the drive to access a random sampling of data from all over the drive. In this case, a lower number is better.

There’s not much you can do to improve the performance of a subpar drive. Check your BIOS to make sure you’re running at the fastest interface speed possible—SATA 3.0 instead of SATA 1.5, for example. Defragmenting the drive might help, but performance degradation over the life of a drive might indicate hardware failure.

Measure Your Overall System Performance

The open-source program COSBI OpenSourceMark attempts to replicate real-world benchmark scripts, similar to SysMark’s and PCMark’s. We’ve found that OpenSourceMark, which uses a number of real-world operations, is one of the better ways to analyze your computer. Install the program and click the “official run” button to start the tests—which include file compression, audio encoding, spreadsheet calculations, and image-editing activities. The program detects multiple cores and automatically reconfigures the benchmarks to take full advantage of your rig’s hardware. And if you just want to test a particular subset of performance—say, file encoding—just select the “custom run” option and handpick your benchmark suites.

OpenSourceMark lets you save information about your CPU utilization to a text file.

OpenSourceMark is a great way to test whether your computer tweaking is actually having a measurable effect on your system’s performance. Do you really need to defragment your drive 12 times a week? How much does your antispyware program actually slow down your PC? What’s the hard benefit of all that extra overclocking?

Test Your Rig's Stability

Prime95 runs your PC at full loads until one of two things happen: You’re content with your testing or your rig shuts down.

Whether you’ve been overclocking an old rig to wring out more performance or you just purchased a new overclocked machine, stress testing your computer’s stability should be high on your priority list. (Stock-clock users can join in the fun too, but it’s not as critical. You can test whether a beta driver you downloaded mucks up your system in some capacity, but for the most part, a stock-clock machine should be inherently stable hardware-wise.)

An overclock can push a rig past safe (or stable) operation. You might not notice this instability or Windows might crash once an hour. Either way, one sure way to determine whether you’ve gone too far is to run your computer like a madman, and if it survives the rite of passage, you’re golden.

We use Prime95 for stress testing in the Lab. In a nutshell, the program calculates new Mersenne prime numbers and taxes the heck out of your processor and RAM in doing so. If you’re on a single-core machine, all you have to do is fire up Prime95 and select the Torture Test from the options menu. Run the test for 10 hours on small FFTs, which nails your CPU, before switching to large FFTs for the RAM.

Owners of multicore machines will want to download the .zip version of Prime95 and extract its contents to a new folder for each core of your machine. Run the program out of each folder, which will open up one instance of Prime95 per core. Click “Affinity” on the program’s advanced menu and set each instance to run on a different CPU core. Dual-core owners should run a small FFT on one core and a large FFT on the other; just double that equation if you’re rocking a quad-core PC.

In the Lab: David Murphy Explains Case Reviews

David Murphy — Tue, 05 Feb 2008 17:10:03 -0600

The art of testing cases at Maximum PC is a lot like the sword ceremony scene in Kill Bill. There’s a lot of razzmatazz and showmanship at first, but in the end, a worthy case is treated with honor and delicacy as it’s gently placed back in the Lab; wretched cases are also moved to the Lab… to be used as pedestals upon which we rest the worthy enclosures.

I’m being only a bit facetious when I say that because reviewing a case really does require delicacy. I start by giving a case’s exterior a full inspection. Aesthetics play the smallest role in our overall verdict, but as our September 2007 review of Dynapower USA’s Hachiman case illustrates, I do point out the look of a case when a vendor tries something new—or when an exterior is worthy of contempt (although I do recognize that one person’s pile of garbage is another person’s Pieta).

The real fun begins once I’ve popped off the side panel—and if that’s not a pleasant experience, the chassis earns its first ding. Inside, I’m looking for elements such as screwless mounts that are easy to use but secure, convenient and accessible drive bays, and cooling potential. Mounting a motherboard in the case typically exposes any flaws in the overall design: We experienced this with an early version of Antec’s Nine Hundred case, which didn’t allow certain cables to be connected. (The problem was fixed prelaunch.)

I like to come at case reviews as if I’m a basic user, and in doing so, I ask myself a series of questions during the review process: Is the case difficult to work in? Is this case easy to manipulate and fill with components? Is there a better way to do what I’m doing? Do I need extra parts, tools, or products to complete my rig? And once the rig is built, are the provided cooling solutions too loud? Does the case adequately muffle my noisy components? Is its cooling sufficient? Does the case lack anything that would be necessary for me to build the perfect rig?

There are two primary case design styles: classic and over the top and gamer themed. Depending on your needs, even a 10 Kick Ass case might not be exactly what you’re looking for.

A case can have a lot of features and still have a horrible design. Conversely, a case can be a little skimpy with its add-ons—holes for water-cooling tubes and included tri-speed fans and LCD display panels—but still deliver an amazing experience for rig builders. Reviewing cases is part exact science, part surprise and delight.

White Paper: How Lasers Function

Gord Goble — Tue, 05 Feb 2008 16:26:14 -0600

Energy injected into a laser’s gain medium excites the atoms within it, causing the electrons circling those atoms to throw off particles known as photons. These photons exhibit the same wavelength and move in the same direction, resulting in a powerful, monochromatic beam of light.

When science-fiction authors got wind of the concept of lasers, they immediately weaved the technology into their story lines as heinous instruments of interstellar destruction—not surprising, when you consider that the word “laser” is actually an acronym for “light amplification by stimulated emission of radiation.”

But as you sit in front of your PC, you’re likely to be in close proximity to several lasers, none of which is capable of setting paper on fire, much less blowing apart a spaceship. The same goes for those traveling shows that use such focused beams of light to create hallucinogenic displays to a soundtrack of Pink Floyd and Led Zeppelin.

Lasers today are the key technology behind CD, DVD, HD DVD, and Blu-ray players and burners. They create the images produced by laser printers, and they precisely track the movement of laser mice. How did a concentrated beam of light become so important to so many aspects of modern computer technology?

Up and Atom

To understand lasers, we must start with the atom, which—as anyone with the slightest exposure to science education knows—is the basic component of just about everything in our known universe. The atom, however, can be broken down into even smaller elements; namely, neutrons and protons, which form the atom’s nucleus. Neutrons and protons exert a positive electrical charge, while a cloud of negatively charged electrons circulate around the outside of the nucleus.

Light—any type of light—is created when electrons are energized by an external source, such as electricity. Once that is accomplished, the electrons move into a higher orbit around the atom, and the atom becomes unstable. This state is only temporary, however; the electrons soon return to their normal orbit, and this is when the good stuff happens. As the electrons return to a state of equilibrium, they release their excess energy in the form of particles called photons: light.

When the electrons inside the atoms of conventional light sources—such as incandescent light bulbs, fluorescent tubes, flashlights, and even the sun itself—are excited, they emit photons randomly. The “white” light generated by these sources contains a wide variety of incoherent rays of different wavelengths (wavelength being determined by the energy difference between the atom’s excited and relaxed states). The light is described as being white because it’s the sum of many different wavelengths. A laser device, on the other hand, is capable of compelling atoms to emit photons in a highly organized fashion.

The Light Fantastic

The key concept behind laser light is stimulated emission. If the photon emitted by an atom encounters another atom with an electron in the same excited state, it can provoke that second atom to throw off a photon that exhibits the same wavelength and moves in the same direction.

A laser consists of a gain medium, which is a material with specific optical properties that render it capable of amplifying light of a specific wavelength. The gain medium is housed in a cavity capped by a mirror at one end and a partially transparent mirror at the other. As energy (in the form of light, or in the case of the semiconductor lasers, electricity) is pumped into the gain medium (which can be a gas, liquid, or solid), it excites these electrons. The electrons then emit energy in the form of photons as they return to their relaxed state.

The photons then bounce back and forth between the two mirrors, repeatedly passing through the gain medium, exciting other electrons and stimulating the emission of even more photons. This cascading effect continues as long as energy is applied to the gain medium. Some of these photons escape through the partially transparent mirror, also known as an output coupler. Since all the escaped photons are of the same wavelength and are all traveling in the same direction, they form an intense, monochromatic, highly directional column of light: a laser beam.

Storage Applications

Semiconductor lasers are the most common type of laser; low-powered semiconductor lasers are used in the construction of everything from laser printers and optical drives to laser pointers and measuring devices. The semiconductor laser in a common CD-ROM drive emits light with a wavelength of 780 nanometers (very near infrared, which ranges from 750nm to 1mm) and is projected through a lens with a numerical aperture of 0.45. As a lens’ numerical aperture increases, so does its ability to create a focused spot of light.

The laser beam is directed at a spinning disc, which has a polycarbonate layer stamped with pits (surface areas without pits are called lands). The polycarbonate layer is backed by a reflective metal (aluminum, typically). As the disc spins beneath the laser, the light passes through the polycarbonate layer and bounces off the aluminum layer. Inside the drive, an optical pickup measures the difference between the pits and lands to create the binary ones and zeroes used to encode music, video, and other types of data.

DVDs pack more data into the same area by rendering the pits and lands smaller and closer together; DVD drives use lasers that emit light with a shorter wavelength, 650nm, projected through a lens with a higher numerical aperture: 0.65. The pits and lands on Blu-ray and HD DVD discs are even smaller and more tightly packed than those on DVDs—players that read these discs use blue lasers that emit light with a 405nm wavelength. One reason Blu-ray delivers more storage capacity than HD DVD, despite both using blue lasers, is that Blu-ray devices use a numerical aperture of 0.85, compared to HD DVD’s 0.65.

Printer Applications

Next to optical drives, lasers are most commonly found in printers. And like optical drives, laser printers utilize lasers that emit light in wavelengths ranging from 650nm to 780nm (with higher-powered models using lasers with shorter wavelengths).
The laser is focused on a rotating drum inside the printer, which is coated with photo-conductive material. The drum initially receives a positive electrical charge from either a charged roller or a corona wire. The laser then emits a pulse of light for each dot that is to be printed, which discharges that area of the drum. Once this pattern of dots is created for the entire image on the page, the printer coats the drum with positively charged toner. The toner “sticks” to the discharged areas of the drum and is repelled by the areas that remain positively charged.

A sheet of paper (which the corona wire has endowed with a negative charge) is then rolled over the drum. Since the negative charge on the paper is stronger than the one on the drum, the paper pulls the toner away from the drum. The paper then passes through a fuser, which melts the toner and bonds it with the fibers in the paper.

More powerful lasers may be capable of cutting through steel, and the Department of Defense has made no secret of its efforts to weaponize laser technology, but the vast majority of lasers are used in peaceful applications such as these.

How To: Become a Gaming God

David Murphy — Tue, 05 Feb 2008 15:22:49 -0600

All right, newblet. You’ve eaten your dog food in Wolfenstein 3D, done your spirit quest in Prey, and even managed to set up a bomb or two in Counter-Strike. If first-person shooters were massively multiplayer role-playing games, that might qualify you to step out of the kindergarten zone. Maybe. The big leagues of head shots, m-m-m-monster kills, and first-person-shooter fragfests have no room for subpar playing performance.

Top players—including PC Gamer’s very own Norm the Intern—all seem to have an innate talent for running-and-gunning. At least, that’s the nice way to put it when you’re on the receiving end of one of their rockets. But being awesome at shooters isn’t just luck; follow our guide to becoming a better gamer, and you’ll be on top of the leader board before you can say “pwnd.”

1. Know Your Maps

The best first-person-shooter gamers spend just as much time researching as they do button-clicking. For even the twitchiest of reflexes is worthless on an unfamiliar map; you’ll be riddled by railguns from every direction as you struggle to find even the most minimal of upgrades to your starting weapon. And in games like Quake, your opponents having quad-damage plus a knowledge of common spawning points equals you minus your body parts—plus an explosion of fire and guts. What fun!

You don’t have to get served up and down the battlefield to begin your most important of research tasks. After all, most multiplayer-themed shooters come with single-player bot modes. Fire up a one-on-one, set the computer to “bunny rabbit” difficulty, and resist the urge to spawn-camp your frustrations away on such an easy opponent. You’re here to research, not eradicate.

The world's top TF2 players (conveniently found on the official Maximum PC server) memorize their maps: it turns the routes, choke-points, and strategies into a chess game... with flamethrowers.

So what are you trying to learn? Start by sauntering through the level to find the spawning points for the map’s many weapons. You’ll want to be able to get to your weapon of choice—newb-cannon rocket launcher, sniper rifle, or some other ingenious combination of death and destruction—from any position on the map (especially the spawn points).
That’s just the beginning. In theory, you’ll work your way up to creating actual routes. You’ll be able to count the seconds between each power-up or weapon spawn. And you’ll be constantly running a loop around all the major power-ups—health, armor, ammunition. Even if your game doesn’t feature these goodies, you’ll want to know all the possible chokepoints, so you can mount the best offensive with each spawn.

2. Know When to Wuss Out

If you’re playing in a professional gaming setting, this tip is undoubtedly worthless. The second your opponent spots you, consider yourself three seconds away from corpsedom. But if you’re playing an everyday match on the Interwebs, or even a match against some of your more talented friends, then you’ll need to suck it up so you don’t suck it down. Humility is an important part of the FPS experience.

What does that mean? Don’t go charging off into battle with your starting weapon, even if your most hated of opponents just ran past the spawn point. You will die. If you’re obviously outgunned in a firefight, don’t keep shooting. You will die. If you’re facing off against a sniper who just head-shot two of your buddies in the face, don’t run toward him. You will die.

When trying to trap an opponent, make sure you’re using a weapon that’s going to get the job done. You’re in for a ride on the pain train if you don’t get the one shot, one kill.

Play smart. Turn tail. Run away, and perhaps you’ll hit a teleporter and confuse your opponent. Or better yet, pull a Macaulay Culkin and set a trap—run through a doorway and immediately hug the wall on the right. Stay put, and if your opponent is stupid enough to just run straight ahead, you might be able to catch him with a quick shotgun blast to the face. Advantage: you.

3. Gear Up

It’s important to customize your hardware for the kind of gamer you are. That includes redoing your keyboard’s keybindings to best facilitate your fragging experience. It’ll add about 10 minutes to your prematch startup time, but the payoff is worth it. Swap the weapons you frequently use to buttons more accessible to your WSAD-style controls. And if you indeed rock with a gaming keyboard, then make sure you’re using its extra input keys to their fullest potential.

Some keyboards come with fancy applications and feature a number of preset hotkeys. Use them as a base to save yourself some tweaking time!

If you can pick up a fancy gaming mouse, do it—you might not see an increase in overall accuracy from higher DPIs, but you’ll likely be able to switch your sensitivity on the fly. Need a little more machine-gun spray action? Kick the mouse up to a high sensitivity and let ’er rip. Camping spawn points in Facing Worlds? Lower your sensitivity and buzz the eyebrows off your opponents. Remember, reacting to an enemy is akin to raising the white flag; you want to anticipate your opponent’s movements at all times.

How2Mini: Waiting for a Respawn?

Here are some quick tips for your next few rounds of gunplay.

300 Pick on the weak. That’s right. We said it. If you’re in a 15-player deathmatch and getting rocked by three or four people you can’t compete against, stop fighting them. Find the guys you can utterly stomp on and hunt them mercilessly. They’ll call you names and hate your very existence, but hey, you’re on the top of the kill boards. They’re just jealous.

Be a Planeteer We might be speaking to deaf ears with this one, but hear us out. In team-based shooters like Counter-Strike and Shadowrun, you need to do just that: act like a team. Fun as it may be to entertain your dreams of becoming a virtual Rambo, it just isn’t going to work. Like wolves, you need to hunt in groups—use each person’s strengths to your advantage. And get on your headset!

Dance, Monkey! Standing still and shooting never works, but neither does jumping around like a chinchilla on speed. Create a dance—a few standard strafing/jumping moves that you’re familiar with, so you can always keep your mouse targeting trained on a player while you’re moving in-game. Otherwise, you’ll spend half the gunfight trying to react to your own dodging attempts instead of your opponent’s.

Talk Like You Mean It Psychological warfare is every bit as important as good accuracy. So the next time you get that sweet head shot, feel free to let your fellow players know just how newb they are in your favorite combination of obscenities, epithets, and physical gestures. It works in every cartoon; it’ll work in your first-person shooter.

Brian Carter's Mystique2

Tom Edwards — Mon, 04 Feb 2008 13:31:45 -0600

When Brian Carter heard that Cooler Master was sponsoring a case-mod contest, he got to thinking about just what it might take to win. Soon enough, an idea came to him: If one case is good, combining two Mystique 631s could only be better.

Brian blended the two cases and carried out the trademark CM wave motif both inside and out to create this sweet-looking media center PC. To keep everything inside looking pretty, he ran the power cables through a piece of 2¼” chrome pipe, which he routed behind the drive cage and underneath the motherboard tray.

The project took two months to complete; Brian submitted his rig on the day before the contest deadline—and won.

When the front panels are closed, the Mystique2 blends in with other A/V components, making it great for living-room use.

The Mystique2 boasts a load of media options, including an iDuo 10-in-1 card reader/iPod dock and two Pioneer slot-loading DVD drives.

This media center PC includes two PCI cards: a TV tuner and an HDTV tuner.

A Mars CPU cooler ensures silent running; Brian hand-cut Cooler Master’s logo from an existing aluminum panel and added it to the fan grill.

For his winning entry, Brian wins a $500 gift certificate for Buy.com to fund his modding madness! See all the hardware deals at www.buy.com.

White Paper: Power Supplies

Mike Chin — Fri, 01 Feb 2008 18:53:41 -0600

It’s important for a PSU to maintain a consistent voltage within a specific range; providing more voltage can lead to a shortened life span for the part.

A decade ago, there were few well-known power-supply brands for DIY computer enthusiasts. Some people sought out specific models normally sold in bulk to commercial system integrators, but none of these products was individually boxed. How dramatically things have changed!

Today, the DIY computer builder has a bewildering array of retail-packaged power-supply choices. Most of these companies source the power supplies from the actual manufacturers and then market and distribute them under their own brands.
So aside from colorful boxes, shiny paint jobs, blinking LED fans, fancy cables, and eye-popping four-digit power ratings, do the new retail power supplies offer any functional advantages over the plain gray boxes of old?

To answer this question, we’re delving into the fundamentals: What are the real functions of a computer power supply?

Riding the Rails

The Power Supply Unit (PSU) converts AC electricity into regulated DC voltages, which it then delivers to the components inside your computer. Several different DC voltages are needed, the main ones being +12V, +5V, +3.3V, -12V, and 5V standby. Each voltage rail has a specific set of functions:

+12V: In recent years, this has become the main rail to power most of the computer’s components. The motherboard uses DC-to-DC conversion of the 12V rail to provide the <1.5VDC needed for the CPU. It’s also used to provide additional juice directly to power-hungry videocards, with direct connection via 6-pin and 8-pin PCIe power connectors. +12V is also used to power hard drive motors and fans.
+5V: The motherboard and many of its components use +5V.
+3.3V: Used to run system memory, videocards, and other circuits.
-12V: Provided for backward compatibility, mostly with some types of serial port circuits, typically with a current limit of <1A.
+5V standby (SB): Always on as long as the power supply is plugged into AC and its main switch is left on, +5VSB is used to power the “soft” turn on/off circuitry in the motherboard that tells the PSU to power up or power down. It is also used for “self-powered” USB devices.

Each output voltage rail has a maximum current capability, expressed in amperes (A). Note that voltage multiplied by current equals power. Normally, the maximum power capability of each voltage rail should add up to total rated power, but this is not always the case. With no-name PSUs, false labeling is quite common; the rated power seems to always be greater than the sum of individual rail power. With quality brands, sometimes the reverse is true: The sum power of individual lines is greater than the PSU’s rated power. This is because the maximum capability of each line cannot be delivered simultaneously without overloading the primary DC transformer. Look for combined maximum current/power ratings.

The main output connectors on modern PSUs are

A 24-pin or 20+4-pin main ATX for the motherboard
A 4-pin ATX 12V or an 8-pin ATX 12V for the motherboard (the 8-pin versions is mainly for high-current CPU and dual-CPU boards)
Two 12V 6-pin and two 12V 6/8-pin auxiliaries for high-power PCIe videocards
A 4-pin “Molex” for IDE hard drive (and other peripheral) power
A SATA hard drive power connector
A floppy drive power connector

Regulate This!

The ATX12V specification calls for a range of ±5% on the +12V, +5V, and +3.3V rails, and ±10% on the remaining lines. The voltage monitoring software in motherboards is not really accurate enough to check on VR; a multimeter with probes across the output terminals is needed. Many enthusiasts erroneously believe that higher DC voltage is always better; in reality, higher voltage can lead to early component failure. What’s more important is that the voltage is kept within specified limits under all conditions.

240VA is a limit on some consumer electronics safety standards. The 18A current limit for 12V was intended to keep the VA in the PSU output cables below that 240VA limit. This requirement is achieved by inserting a simple limiter to keep the current below 18A on any 12V line cable. With several cables, the total 12V current could exceed 18A, however. But marketing materials have exaggerated this technicality into “multiple 12V rails”; some PSUs are even advertised as having four or five “independent” 12V rails. In reality, most PSUs limit the current on each 12V cable to <20A, and virtually none have more than one 12V rail. All the 12V wires connect to the same 12V transformer. The exceptions are some extremely high-power units (~1kW), in which having two separate 12V circuits can actually make engineering-design sense.

Power Shift

A desktop PC does not require a constant level of power. The power requirements depend on what the PC is being asked to do. Most home PCs remain in low or idle mode about a third of the time that they are powered on.

When the CPU or videocards are at full load (during intensive video or photo editing, serious number crunching, or extended 3D gaming), the power demand can jump to double that of idle load. In most cases, recommendations by manufacturers and technical magazines about how “big” a PSU should be are based on the maximum possible theoretical load of the system components, plus added headroom capacity. This results in unrealistically high power recommendations. The recommended PSU power rating is more than double that of maximum loads seen in real-life applications.

Power Conversion and Efficiency

Computer PSUs are switching mode types, which means that the PSU switches on and off upwards of 100,000 times per second; this provide relatively high efficiency at low cost compared to linear (non-switching) power supplies.
The conversion from AC to DC always requires some signal filtration, and there’s some energy loss into heat; the lower the loss, the higher the efficiency. Efficiency is defined as the ratio between DC output and the AC input required for that output, and it is expressed as a percentage. Efficiency does not stay constant; it varies somewhat with power output.