• Tech Expert: how to destroy your data

    • Image credit: Headcase design
    • Modeo"â„¢s Smartphone receives DVB-H video.
    • Some US government agencies recommend physical destruction of media before disposal.
    Date:28 February 2007 Tags:, , ,

    An angle grinder is one option…

    Naked PC. Is that cool, or what?
    A computer-enthusiast friend of mine operates his PC with the case open. He claims that it helps cool the computer. Is he right?

    An open case can make things a lot cooler – if you put a full-size box fan right next to it. Otherwise, your friend’s system is probably sucking in lots of dust, bugs and pet hair in exchange for a marginal or nonexistent cooling increase. In a properly designed PC case, the fans create a ducted airflow that enters in the front, passes over the CPU, power supply and other heat-producing hardware (components that often have their own heat sinks and fans), and exits out the back.

    By controlling fan speeds and where air leaves and enters the case, the engineers can guarantee that you’re pulling in fresh, cool air and ducting out hot air – rather than fuelling a vortex that spins the same hot air around the quickly heating CPU. In other words, a closed case actually helps direct the air to where it should go.

    So tell your friend to close his case and make sure that he doesn’t have any obstructions that would impede the flow of air from the front to the back, such as extraneous cables. Don’t believe me? Many free software programs, such as SpeedFan, allow you to poll your PC’s built-in temperature sensors to do your own testing.

    Trying to teach an old card new tricks
    Will a new Wireless N router increase the range and speed of my Wi-Fi connection if my laptop only has a Wireless G card?

    Range? Probably. Speed? Less likely. Part of what gives the emerging Wireless N (or 802.11n) Wi-Fi standard its superduper speeds – up to 540 megabits per second (Mbps) with a strong tailwind – is something called Multiple-Input, Multiple-Output, or MIMO. The technology is pretty easy to understand: multiple antennas are used to send and receive data using a number of identical signals simultaneously, increasing the overall data throughput.

    The 802.11n MIMO system uses two technologies to increase the range of the more established 802.11g wireless hardware. They’re called cyclic delay diversity (CDD) and maximal ratio combining (MRC). Winston Sun, a member of the technical staff at Atheros, a company that designs Wi-Fi chips, explains: “CDD allows the access point, with its multiple antennas, to transmit the exact same data, but with a cyclic phase shift that prevents a standing wave pattern.” Translation: using more antennas to transmit the same data boosts the signal, while a slight shift in the timing of the signal helps prevent a device – say, your laptop – from languishing in the “trough” of a radio wave.

    MRC works in reverse. It reads the signal from your 802.11g hardware on both antennas and compares them to enhance the “readability” of the signal.

    CDD and MRC are optional parts of the 802.11n specification – there’s no guarantee that these features will be in your Wireless N access point – although nearly every Wireless N access point on the market has CDD and MRC built in.

    What’s the payoff? You could see a 30 to 50 per cent increase in range with most Wireless N routers, even when communicating with older 802.11g hardware. As for enhanced data throughput, don’t expect any miracles, but Atheros plans to release a firmware update for its chipset in the second quarter of this year that will support the double-speed Super G technology on its Wireless N routers. That will bring 802.11g speeds up to around 108 Mbps, if the card supports it. Bear in mind, however, that many current Wireless G access points already reach these speeds, so these N routers are actually playing catch-up.

    Set My DVD Free
    My Macintosh MacBook has a slot-loading optical drive. About a month ago, I got a DVD stuck inside. The eject button isn’t working. Is there a manual way to pop out the disc?

    There is no physical button or trigger like those on tray-loading drives that can be pushed in with a paper clip. And you don’t want to fish around inside the drive slot because you risk scratching the disc, as well as damaging the drive. The first thing you should try is to reboot the laptop, holding down the trackpad as it boots. That sends a hardware-level “eject” signal to the drive. If the drive can still eject the disc, it will. If not, then your drive is probably shot.

    If you must retrieve the disc, you can try to use a credit card to slip in the slot, pop the disc off the spindle, and fish it out. But, as we mentioned, you may end up damaging the disc and the drive for good.

    Otherwise, it’s off to the repair shop for you, where you can suffer in line with the other folks whose Macs have gone south.

    Encrypt keeper
    I’ve been told that when I use my credit card or give private info over the Internet, I’m supposed to look for the SSL security protocol. What is this and how does it work to secure the transaction?

    Secure Sockets Layer (SSL) is a form of data encryption. Think of it as a lockbox for your data, packing up normal Web traffic and delivering it signed and secure from your browser to your server of choice. The SSL “key” is passed from the server to your browser, which verifies its validity by checking with a third-party “certificate authority”.

    Major certificate authorities store a copy of their keys with your browser, so that the process of verifying the transaction happens automatically. Sometimes your browser will prompt you with a pop-up warning that it cannot verify the validity of the SSL key and will ask if you’re willing to trust the remote server from which the certificate is being sent. If this warning is in response to a visit to a site that you intended to view, feel free to accept it – a non-authorised certificate doesn’t necessarily mean that your connection will not be encrypted.

    How do you know you’re on a secure Web site? First of all, the address will start with “https://” instead of just “http://.” Also, most browsers display a closed padlock in the browser frame.

    DIY Hi-Fi
    I’ve just bought a car stereo that can play DVD-Audio discs. Can I burn these myself?

    The DVD-Audio format has many advantages over CDs – 5.1-channel surround sound, sample rates up to 192 kHz, and 24-bit audio that is closer to the quality of the original recordings. Authoring your own DVD-Audio discs, however, can be tricky. Until recently, only pro-level software had the appropriate licences to authorise you to master your own DVD-Audio discs. Now, new consumer software such as Ulead VideoStudio 10 Plus (about R600 from www.ulead.com) lets you make full-blown 5.1 surround-sound discs.

    The real question is where you’re going to get the high-quality surround-sound tracks to put on your DVD-Audio discs. You can’t copy existing DVD-Audio discs: it’s illegal under the Digital Millennium Copyright Act, despite the availability of online tools that will allow you to do so. And no major online music service offers DVD-Audio songs for download.

    In fact, unless you are recording your own music in a nice home studio, you probably aren’t going to have the high-quality audio files necessary to justify burning a DVD-Audio disc. Instead, your only option for DVD-Audio authoring is to fill up a disc with MP3 or CD-quality audio that would be just as well served by a CD.

    Emerging Tech
    Digital Video Broadcast

    Many wireless carriers currently offer streaming TV over their high-speed 3G networks, but video feeds chew through battery power on handsets and could strain the capacity of networks if widely used. The new Digital Video Broadcast-Handheld (DVBH) standard promises to solve those problems by broadcasting television programming to mobile phones in power-efficient bursts of data that are independent of the cellular signal. The first DVB-H service provider, Modeo, is beginning testing of its service in New York City this year.
    – Glenn Derene

    Next big thing
    isted Web search

    Algorithmic search engines, such as Google and Yahoo, have redefined how we gather information and made possible the Web as we use it. But critics believe that, for some subjects, no machine’s computational analysis can replace good old-fashioned human thinking. Not yet, anyway. The new www.ChaCha.com search engine, therefore, relies on “expert” human guides who interact with searchers via real-time chat. These online helpers then sort through the hits provided by an algorithmic search and handpick the most relevant results.

    ChaCha is targeted at consumers who need specific results, but don’t have enough familiarity with their desired subject matter to search for it efficiently. An algorithm matches each query to a guide with a professed expertise in the subject matter. The guide then continues the search, narrowing down the results based on the user’s feedback. Results from each search are indexed for future use, so in theory, ChaCha gets smarter over time.

    Human-assisted searches have the potential to fill the gaps where traditional search engines fail – provided the guides have genuine expertise. We tested the service using multiple searches for obscure 1980s TV trivia information. ChaCha guides found the right info, but searches took up to 8 minutes, compared with 1 minutes to get the same results, using the same queries, in Google. ChaCha.com is still in beta testing, so it may get better over time, but so far it seems that human advice can be as hit-and-miss as anything else on the Web.
    – Erin McCarthy

    How to absolutely, positively destroy your data
    When you’re getting rid of an old PC, sometimes erasing your files isn’t enough. Here’s how to make sure gone means gone.
    By Anthony Verducci

    The file-by-file method
    1. Individual files eliminated, software remains intact
    If you are giving your computer to someone else, you don’t necessarily want to eliminate all the valuable software along with your private data. Dumping individual files in the ordinary way doesn’t make them unrecoverable; it only makes the space on the drive occupied by those files available for overwriting. To completely destroy a file, use a data-shredding program such as Digital File Shredder from StompSoft (www.stompsoft.com; about R210). It takes a conventional “erase” a step further by actually writing over the file.

    The whole-drive method
    2. Entire drive is permanently erased, but still usable
    Completely reformatting your drive may seem more permanent than simply erasing the files, but this method doesn’t eliminate data either – the information can easily be restored using off-the-shelf data-recovery software. Many of the best data-erasing programs come from the same companies that produce data-recovery software. DataEraser, available from Ontrack (www.ontrack.com), completely overwrites the drive. Set aside some time: this can take hours on large hard drives. The process is, of course, irreversible.

    The power tool method
    3. Data is gone, hard drive is toast
    There is no better way to completely annihilate your data than to render the device that stores it unusable. We still suggest a software shredder first, but if your personal data security justifies the extra effort, put on protective eyewear and gloves, then break out the power tools. Drilling four holes through the platters will ensure that they never spin properly again. Better yet, unscrew and remove the top lid of the drive, and go at the platters with a sander or angle grinder. Scuff the surface of the platters until all the shine is gone.


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