How Google Calendar Works

The Google Calendar layout is fairly simple. A miniature view of the calendar appears in a column on the left side of the screen. It displays the current month and highlights the current day. A larger viewing area takes up most of the rest of the screen. The Google Calendar has multiple viewing options. You can choose to view the calendar by day, week, month or a view that presents just the next four days. You can also choose an "agenda" view, which presents all scheduled events as a list rather than as a calendar view.

No matter which view you're in, you can block out time on the calendar. In most views, Google Calendar allows you to schedule appointments or events with a simple click-and-drag interface. In the day, week and next four days views, you can block out time in half-hour increments by clicking and dragging down the appropriate day. Google Calendar then prompts you to fill in details about the appointment. In the month view, you can block out time for multiple days. This is particularly useful if you need to set aside time for trips and vacations.

You can keep appointments simple with just a subject header, or you can choose to add more details. You can include a location for the appointment and a short description. You can also use the "repeat" function for events that occur regularly, such as a weekly meeting or annual event like birthdays.

Most of these functions are similar to the features of other calendar software products on the market. As part of an effort to differentiate Google Calendar from its competitors, Google incorporates other features that take advantage of Google's capabilities. Perhaps the most notable Google offering is its search function. In Google Calendar, you can use Google's search technology to search not only your own calendars, but also any public calendar on Google's system.

Let's say you're going to a conference. The administrators of the conference have made the event's schedule available online through Google Calendar. You can use the search function to find the event's calendar and synchronize it with your own. Google Calendar returns a search engine results page (SERP) specifically formatted to show calendar results. You can select the appropriate entry in the SERP and Google Calendar takes care of the rest. Now you've got the detailed schedule imported into your own calendar.

Perhaps you own multiple calendars, some of which are public and others that aren't. You can use the search function to look for specific events within your calendars. Google Calendar returns a SERP showing you where specific scheduled events fall on each of your calendars.

These features are just the tip of the iceberg for Google Calendar. Want to learn about more advanced features? Head on over to the next section.

Many of Google Calendar's advanced functions rely on the fact that it's a Web service. With most other calendar software, you'd either access the program from your own computer's hard drive or you'd store the application on a local area network (LAN). With Google Calendar, the entire application and all its contents are on the Web.

One of the Web services Google takes advantage of is short message service (SMS) support. This is the format cell phones use to send text messages. Users can allow Google Calendar to send reminders via SMS to their cell phones. As a scheduled event draws near, Google Calendar sends an alert via SMS to a phone number registered by the respective user. While Google offers this as a free service, users may have to pay their cell phone service providers if they go over their monthly text message limits.

Google fosters a growing community of developers who use Google's application programming interface (API) to build new programs based off Google technology. Google calls the resulting applications Google gadgets. Many developers design gadgets to work with existing applications, including Google Calendar. Gadgets allow users to insert special events into a calendar. The options are practically limitless. Examples can include everything from inserting a relevant photograph to attaching a Google Map showing the location of the event.

Google Calendar makes it pretty easy to send invitations to other people. First, you create an event in your own calendar and fill out the details. Then, you can click on the "add guests" option. This opens up a field in which you can type e-mail addresses. Once you save the event, Google Calendar sends e-mails to the invite list. As guests respond to the invite, Google Calendar displays the results within the event listing on your calendar.

If a user chooses to share or publish a calendar, other users can leave comments on event entries. This allows people to discuss upcoming appointments or debrief after a meeting. The event page becomes a forum for guests and calendar viewers.

What does Google use to keep the Google Calendar system up and running? Find out in the next section.

If you're familiar with Google, you probably know that they're secretive when it comes to their operations. There's not a lot of information available on the system Google Calendar uses. Still, there are some aspects of Google's operations that are public knowledge. As for the rest, we can make a few assumptions on what's going on behind the scenes.

It helps to imagine the Google Calendar system as a client/server system. A client is an entity that requests a service. The server is the part of the system that provides a service. Both the client and the server may have special software allowing them to interact with one another. What's more, it's possible for a single computer to act as both a client and a server.

On the server side of Google Calendar, Google uses the Java programming language to build applications. Sun Microsystems developed Java as an object-oriented computer programming language. Programs created with Java can exist independently of other programs. It's the Java applications that handle all the data on the back end of Google Calendar.

Google Calendar users see the client side of the system. This consists of a Web page enhanced by Javascript. Javascript and Java aren't the same thing. The Java language allows programmers to build programs ranging from full applications to smaller applets. Developers use Javascript to beef up Web services. They can't use it to build programs that work outside of a Web browser experience.

That about wraps up everything Google outsiders know about the Google Calendar system. But we can make a few guesses about other details:

Google doesn't say how many machines it dedicates to run services like Google Calendar. But Google has several huge datacenters. A datacenter is a building that shelters computer equipment, usually stored in metal shelving units called racks. A large datacenter might house thousands of servers. How many of those servers run Google Calendar? That's only known to people inside Google itself.

Want to learn more about Google applications and related information? Schedule some time with the links on the next page.