Speeds and Feeds

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November 11, 2009 6:10 AM PST

Wrapping up Speeds and Feeds, part 3: Ruggedness

by Peter Glaskowsky
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As I continue to wind down Speeds and Feeds, I picked ruggedness as the topic for part 3.

In part 2 of this wrap-up series, I on Tuesday discussed reliability, suggesting that an increasing portion of the transistor budget in personal computers should be used to avoid, detect, and recover from hardware, software, and data errors.

Ruggedness, the ability of a PC to survive adverse physical conditions, complements reliability by further increasing the practical availability of a PC to do useful work.

As with efficiency in power management (part 1's topic), this is an area where PCs can learn a lot from cell phones. I expect my cell phone to continue operating normally unless it's physically damaged--and I expect that it will not be damaged even by fairly rough handling.

PCs, by comparison, are pretty fragile. I know that if I drop my laptop, even if it falls only a few feet to a carpeted floor, there's a good chance it will be damaged. The LCD could crack, the case could bend, the hard disk could crash, the battery latch could break. In fact, I've managed to do all of these things to one or more of the 15-plus laptops I've owned and used since 1984.

Not all laptops need to be rugged; for example, some laptops are used as small-footprint desktop computers and rarely moved at all, so ruggedness would be an unnecessary expense.

There are many situations, however, where greater ruggedness is obviously valuable: laptops for students (even in a classroom), field photographers, mechanics, factory workers, the military, and so on.

Some companies already make rugged systems for these applications, but demand for such systems is low, and they require a lot of additional engineering. The combination of small quantities and extra design work leads to very high prices; it isn't unusual to see rugged laptops with the features of a typical low-cost notebook selling for $4,000 or more.

There have been very few standard mass-market personal computers with any real degree of ruggedization. In the old days of 8-bit microcomputers, some consumer-oriented systems such as the popular Atari 400 and Commodore 64 were fairly robust due to heavy plastic cases designed to survive casual home use, but these weren't portable machines.

In the mid-1990s, Dell's Latitude line earned the favor of serious road warriors in part due to a high degree of ruggedness, if only in comparison with other mainstream laptops. Sometimes these Latitude models were the only survivors of annual notebook torture tests run by PC Computing magazine.

Panasonic's Toughbook line took over later in that decade as the first truly rugged notebooks. (I have a Toughbook 25 myself; alas, it's dead.) It's easy to see how these machines differ from ordinary notebooks: heavy magnesium casings with stiffening ribs to resist twisting, shock-mounted hard disks, water- and dust-resistant connectors, and so on. They aren't suitable for most people, though.

Three trends are bringing rugged systems closer to the mainstream today.

First, portable PCs are becoming increasingly more integrated into our daily lives. As power efficiency improves to the point that we can run them all day, portable machines will be even more important to us. But if these devices aren't rugged, we won't really be able take them with us as often as we'd like.

Notebook design

A simplified view of a small ruggedized notebook that I designed in 2005.

(Credit: Peter N. Glaskowsky)

Second, the components themselves are getting smaller, lighter, and in some cases more rugged. It's possible to buy a decent dual-core CPU that doesn't need a huge heat sink. Solid-state disk drives are a huge step forward; and with 128GB of capacity requiring only 32 flash chips, they can be much smaller than traditional hard disks. Smaller, lighter components are easier to support and protect.

Third, materials science is making a lot of progress. The glass used in LCDs is much better today than it was a decade ago--better able to absorb shock and flex a little when needed. (It's actually a little scary just how flexible the displays of some super-thin notebooks are.) New chassis materials such as milled aluminum and CFRP (carbon-fiber reinforced plastic) can produce very strong machines, though in most consumer systems they're used to reduce weight instead. In the near future, carbon nanotube-reinforced materials will become available in commercial quantities; while expensive, they will be very strong.

These new materials can be used in new ways to make very rugged machines that don't have to cost dramatically more than existing systems.

In 2005, as a practical exercise, I designed a small notebook with a milled titanium case and a novel mechanical design that provided exceptional stiffness. With a fixed battery and few external connectors (another improvement enabled by new technology), it would have provided Toughbook-like ruggedness in a very small and convenient package.

That design didn't go anywhere, but there are plenty of designers out there. I expect that someone will develop something similar before too long.

The current Netbook craze is directing a lot of attention to ruggedness as a design goal. These machines are small, light, and obviously portable, but they tend to be cheaply made and more fragile than many consumers would like. Adapting these designs to more rugged enclosures would add significant cost, but I think there's a good market for such machines.

July 5, 2007 5:00 AM PDT

The Gizmo Report: Sennheiser's HD-280 headphones

by Peter Glaskowsky
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I like to listen to music. I fell out of the habit for a while, but then I got an iPod, which got me interested again. Now I probably buy more CDs every three months than I did throughout the 1990s.

I'm addicted to New Music Tuesdays on the iTunes Music Store, mostly because of the "Free on iTunes" section. There's a lot of good music out there! And a lot of bad stuff, too, but when it's free, that's not so much of a problem.

Oddly, I can't seem to get interested in radio, whether delivered by terrestrial broadcast, satellite, or Internet. I just prefer to be my own DJ with iTunes on my MacBook Pro. I have a smart playlist that shows all my 4-star and 5-star music in reverse Last Played order, so it's easy to find something I like that I haven't heard recently.

I generally prefer to listen with headphones, even at home, where I use and love the HD 595 from Sennheiser.

But for the last couple of years at work, I've been using a cheap pair of headphones that happened to be the only acceptable closed-back product in stock at the local Fry's Electronics the day I decided to go shopping. Most headphones these days seem to be the open style, like the HD 595, but I figured I'd be polite to the people in adjacent cubicles at the office and keep my music to myself.

Finally I got around to upgrading, and I chose Sennheiser's HD 280 Pro.

I won't attempt to give a sound-quality analysis; I haven't been trained in that particular style of writing. Suffice it to say that the new 'phones sound excellent, much better than the cheap pair they replaced.

Unfortunately, I really wasn't happy with the fit. I had to choose between an acceptable level of pressure on my ears and a good fit for the headband. It was clear I had to adjust the tension of the headband, but it isn't designed to be adjusted.

Carbon-fiber stiffener

A piece of carbon-fiber reinforced plastic to be used as a stiffener for the Sennheiser HD 280 Pro headphones

(Credit: Peter N. Glaskowsky)
After studying the problem, I realized that if I could just straighten out the curvature of the top of the headband, I could get the fit I wanted. I measured the size of the stiffener I needed: 23mm wide, 80mm long, preferably not more than 1.5mm thick. Initially I figured I'd use a scrap piece of titanium for this purpose, but then I remembered some carbon-fiber scraps I had left over from panels I'd made for an earlier project, and one had a nice section remaining of just the right size. CFRP (carbon-fiber reinforced plastic) is much easier to work than titanium. I cut the piece I needed with a hacksaw, then smoothed and rounded the edges with a belt sander.




The stiffener installed

The stiffener installed on the headband of the HD 280 Pro headphones

(Credit: Peter N. Glaskowsky)
The next day at the office, I removed the padded cover from the headband, attached the stiffener to the headband with several loops of strapping tape, and put the cover back on-- that was difficult because it was already a fairly snug fit. But it was made of vinyl, so it stretched enough.

The last thing was to add little rubber bumpers to the top outer surface of each earpiece to adjust the earpiece angle and balance the forces applied above and below my ears. (I'm not providing a picture of these bumpers because they're pretty ugly right now. :-)

And now... they fit perfectly, look almost unchanged, and sound great.

So if the shape of your head is within their adjustment range, or if you have some carbon fiber sitting around to make this kind of adjustment (I'm pretty sure titanium will also work), I can heartily recomment Sennheiser's HD 280 Pro headphones.

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About Speeds and Feeds

Silicon Valley-based computer architect and chip analyst Peter N. Glaskowsky attends a variety of industry conferences throughout the year to meet with industry thought leaders and dig into the future of computing technology. In Speeds and Feeds, he analyzes trends in system architecture and interface design, as well as market and political pressures surrounding those trends. He is a member of the CNET Blog Network and is not an employee of CNET. Disclosure.

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