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The View From Here: Time Waits For No Mac
August 1996
The Macintosh file system keeps track of when you've created and modified files. Your backup software - and I know you all back up on a regular basis - requires that the time on your Mac is always correct. This is doubly important if you're doing backups across a network; then all the machines have to be in sync.
The more you use your Mac the more pervasive is the notion of time (and the related notion of location). Time is a global property; your current time depends on when on the planet you happen to be. So it's not surprizing that we start our Mac adventures in time-keeping with the Mac control panel (shown at right). I typed in "San Francisco", then Find, then Set. Now I'm in San Francisco. (This column was written with MacOS 7.5.3 in mind; earlier versions of the operating system may not follow exactly.)
Our next stop is the Date & Time control panel, shown below. You can use this to confirm that your Map settings took. You can also set the Daylight Savings Time state as appropriate; it matters.
Peeking from behind the city selection dialog box are the words Current Time. But what would be the use of manually doing something? Eschew this in favor of doing somehing automagically via the intelligence built into the Internet. How? Just as there's a File Transfer Protocol (FTP) there's a Network Time Protocol (NTP). You'll need to get an NTP client for Macintosh such as Network Time by Pete Resnick. (That link will show you the US English, French, and Dutch localized versions and an English manual.)
An accuracy of two seconds is more than enough for my uses. That's an outside limit, the time is usually accurate to milliseconds. Because I've properly set my Map control panel I can tell Network Time to use those settings. The other settings control how often Network Time sets the time on my Macintosh. I've found that once every 24 hours is quite generous; the Macintosh system clock is accurate enough to hold time for that long. I've set Wait for MacTCP because I don't want Network Time to cause "FreePPP" to dial Sirius upon startup. That's almost the end of my canned lecture on time and location on Macintosh. But there's always a little more. I use several applications to keep track of time on my machine, both my local time and the time of friends and relatives around the world. The Date & Time control panel includes a menubar clock, shown below (in red digits). (The menubar clock functionality is available to pre-MacOS 7.5 users as SuperClock.)
But what about the time in other places? One useful tool is WorldClock Lite (shown below) by Leighton Paul.
It's a geochron for Macintosh. You'll see the terminator sweep the globe, five analog clocks will show you the time at selected places on the globe, you'll be able to calculate how far away places are from your home, moonrises and sunsets in the future, and other things. (Notice that the clock faces change colors depending upon the state of daylight at the location. Nice touch.) The Lite version allows you to to select from a large number of cities. The Pro version has a bigger image, seven clocks instead of five, and a larger (and extensible) database of cities.
But drawing the Earth isn't useful enough for inclusion in my Hall of Fame. I use XEarth's advanced features (some of which I requested from Johan) to pull names from the Map control panel's city database (which I've vastly expanded) and to draw into the Finder desktop. That way I can watch the terminator (the shadow of night give way to the light of day) sweep across the area between San Francisco and Europe, where I friend is vacationing. (This is a thumbnail image; mouseDown on it to see the full-size image.)
So we come to the end of this month's tour. I hope that you learned something new about how time and space relate to your Macintosh. See you in 2678400 seconds, give or take a few.
Michael 'Mickey' Sattler and his cat Copernicus live on the top floor of a Victorian in the Upper Haight-Ashbury neighborhood of San Francisco. Michael works on the net via a wireless Macintosh setup out of The People's Café on Haight Street. These days he's programming in Perl, mating a database to the World-Wide Web.
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A 
I've configured Network Time to query the NTP server at the Jet Propulsion Laboratory of the National Aeronautics and Space Administration, jane.jpl.nasa.gov. (If you choose another server please make sure that you're using a secondary time server. If this means nothing to you, worry not.)
But my favorite related application is XEarth for Macintosh by Johan Lindvall. XEarth draws a representation of the planet Earth in a window or in the Finder desktop. The image can be updated at a user-selectable frequency, so it "rotates" in time to the planet. City names and location - from an internal database or the locations known to the Map control panel - can be drawn over the planet image, as can a grid. The point of view can be from the position of the sun or at a fixed location over the planet.
