Internal memory functions like an 8MB SD card. POIs, routes, tracks, and small detail maps can be stored here as well. SD is recommended as the first choice, as data is less susceptible to loss.

Of course, units like the Magellan Explorist 210™ that do not have expandable memory have only internal memory.

Files can be deleted, renamed, copied or moved while connected to a computer. Without being hooked up to USB, you can move or copy files between the SD card and the internal memory. This gives the potential of easy "in the field" swapping of multiple waypoint files between 2 owners of eXplorists with SD cards.

Despite having access to some of the most accurate timekeeping devices ever built, the time the Magellans use for position determination and the time displayed to the user have little resemblance. In order to bring them back into step, a full clear of memory is required.

This trait is shared with the Meridian, SporTrak and even Map 330 models.

The firmware contains an almanac that knows which satellites may transmit WAAS signals and which do not. The satellites send updates for this information. But there's a kink.

The Magellan firmware knows that satellites PRN 122 and PRN 134 are the WAAS satellites over the U.S. For over a year before they were scheduled to be shut down, these satellites broadcast the update that said the new WAAS satellites were PRN 135 and PRN 138. If your Magellan Explorist 400™ was turned on and received a WAAS fix during this time, life was good. On July 31, 2007 the satellites PRN 122 and PRN 134 were retired.

Now it gets ugly. If you do a 'reset all' on these models, they revert to the factory table that "knows" that the WAAS satellites are 122 and 134 and will continue to look for updates from them. Of course, it never finds them and thus, you will never get WAAS. The same thing happens if your unit wasn't powered on in a WAAS area from early 2006 to mid 2007.

Now it gets uglier. If you have a unit that was manufactured after that time, it never got the update and will continue to spend eternity looking for WAAS on satellites that are no longer transmitting valid signals.

For several months, Magellan stated they have no plans to release updated firmware to address this. Units being marked as "WAAS Ready", yet they'd never get a WAAS fix. Users of units that weren't powered on during this time, have had to do factory reset (typically to get around other firmware defects) and new purchasers are unhappy.

But things change. In Feb of '09, Magellan did release a firmwware update for the WAAS fix for the Explorist 500/500LE/600, Explorist 400, and Explorist 210.

The multiple versions for each of the above are for subtly different hardware builds that require different code. Oddly, for the U.S. models, the "new" versions are a smaller version number and less feature-laden than the European ones which restored many of the screens that were pesent on Meridian family.

For tracking, just connect the GPS the Mac in NMEA mode. OS/X will create a virtual serial port that can then be used by your favorite Mac application.

For waypoint, track, and route transfer, configure the unit for File Transfer mode. It will show up as a disk drive in /Volumes and files may be freely copied to and from it by Programs such as GPSBabel for Mac or MacGPS Pro.

For Map transfer, there is no known native program for Mac that will create map regions. Once the regions are created on Windows, you may use a Mac to copy region to the GPS memory as you would an external card reader. This is handy if you're travelling with a Macbook and have borrowed a Windows system to create map regions for a long trip and have a "canned" set ready to copy to your GPS.

Virtualization using programs like VMWare Fusion or Parallels is another option for those that need to generate maps for upload to their GPS on a Mac.