Navigating a GPS update

My GPS unit says it needs an update. What do I do?

Many Global Positioning System devices flash a warning after a year or so, urging you to get the latest maps. Some may also be programmed to look for new travel and points-of-interest information after a period of time.

How you update the device depends on the manufacturer. If you can't find the manual, check the support area of the company's website.

Some units can wirelessly download updated information. Most inexpensive portable models require that you update the GPS device using a computer. This means installing software that came with the device and connecting it to the computer with a USB cable - both of which were probably in the box when you got it.

Once the GPS device is linked to the computer, follow the manufacturer's instructions for downloading updates. This may mean visiting the company's website or starting the GPS desktop software on the computer to have it scan for updates on the company's servers.

In addition to maps and travel information, there may be fixes for the unit's internal software (called firmware) to install. (Some models may require use of a Secure Digital memory card to add or update data.)

For a full set of new maps, most companies will sell the latest versions on a CD or DVD, priced from $70 to $100. Once the disc arrives in the mail, insert it into the computer's drive with the GPS unit connected and follow the onscreen instructions.

Where do I go in Mac OS X to see how much memory is installed in the computer?

One quick way to see what is under the hood is to go to the Apple menu in the top left corner of the Mac's menu bar and choose the "About This Mac" item. The box that pops up displays the version number of the operating system, the speed of the computer's processor, the amount of memory installed inside, and the name of the start-up disk the Mac is currently using (typically the name of the Mac's hard drive).

To see even more details, click the "More Info" button in the box. This opens up Apple's built-in System Profiler program. (You can find the System Profiler in the Utilities folder inside the Mac's Applications folder.)

Clicking on the Memory line in the System Profiler box will tell you even more about your computer's RAM, including the serial numbers of individual chips.

The System Profiler is also a great place to look to see what kind of graphics card is installed, which can be helpful when trying to figure out if the Mac meets the system requirements for certain video games. By clicking on other options in the System Profiler, you can also see such things as the types of discs the Mac's CD or DVD burner can handle or the Internet Protocol address of the computer.

On Mac laptops, clicking the Power line in the System Profiler box shows information about the computer's battery, including its capacity, current status, and the number of charging cycles completed.

If your new year's resolution was to read more books, but you find you cannot get away from your gadgets, check out DailyLit (dailylit.com). Once you sign up and pick an electronic book from its library, the site regularly sends out installments of your chosen title as e-mail messages or as an RSS feed that you can read on a mobile phone or computer. Many books, including classics in the public domain, are free; more contemporary titles cost about $5 to $10.

J. D. Biersdorfer writes for The New York Times.