iChat

Built into Apple's latest OS, 10.2 code named Jaguar, iChat is billed as making instant messaging even easier. This latest iApp is automatically compatible with AOL's Instant Messenger and allows .Mac users to join any AOL chat room simply by typing in its name.

In additon, Apple's new Rendezvous technology (also built into 10.2) allows you to see users on your local network without knowing their screen names. A log keeps track of your messages for increased productivity and iChat even integrates with the built in Mail program in 10.2 to make keeping track of addresses in different places a thing of the past.

iChat makes it simple to send any type of file, photo or Quicktime movie to who anyone you are chatting with. It will even display it right in the chat window so there is no need to launch another window from a different application.

Extras include an advanced graphic interface, and new icons and thought bubbles. Utilizing Apple's signature drop and drag technology you can even share your own photo with friends that will appear in their chat window whenever you message them.

iChat has several key files scattered in obscure places of the OS. strings reveals several interesting items in /System/Library/PrivateFrameworks/InstantMessaging.framework/iChatAgent.app/Contents/MacOS/iChatAgent, which is the file that does all the communicating. iChat is only a frontend to that daemon.

• Various references to "the %@ service", suggesting multiple-service support
• jabberConnection:rosterReceived:
• jabberConnection:presenceSubscriptionRequest:
• jabberConnection:presenceStatusReceived:
• SubNet %@: P2PJabber connection opened, sending %i pending message(s)...

SubNet appears to be the Rendezvous service, which in turn appears to be based on Jabber. Real Jabber support could then be added at a later date, much easier.

iChat also has some key issues with AIM protocol support on my machine. Occasionally, on joining chats, the program barfs to console.log about the room already being registered, requiring you to quit the program to join chats. Considering there's only been one update since Jaguar came out, I'm not surprised. Also, when I recieve bogus messages from programs designed to crash Windows AIM, iChatAgent will crash 1 out of 10 times, leaving an error saying that iChat lost connection to the Agent. Quit, relaunch.

iChat is an instant message client that comes with Mac OS X

iChat was first released as part of Mac OS X 10.2 Jaguar, where it was part of the default installation and even installed into the Dock as an AIM icon with a blue speech bubble. It worked with AOL Instant Messenger through a deal with AOL, where they were given access using the OSCAR protocol, meaning they were allowed official access to the network as opposed to the other third-party clients. It also allowed you to use a mac.com account as your screen name. It had features like beautiful speech bubbles as IMs (you could turn it off if you desired), and links to the OS X Address Book, where screen names would be linked to the person's real name. It also offered Rendezvous support (now called Bonjour) using the Zeroconf standard, allowing others on the LAN to IM each other and share files with drag-and-drop without any special network configuration. It also allowed you to save your IMs in log format and can run as a background service with iChat closed.

Later on, before Mac OS X 10.3 Panther was released, Apple announced "iChat AV," which allowed full-screen 30fps videoconferencing using firewire webcams and broadband. Apple began selling the iSight for this application. It was available as a limited time beta for Jaguar users and touted as a major selling point in Panther. It also allowed voice chat in an easy interface and the icon changed from a blue speech bubble with an exclamation point to a new camera icon. Bluetooth headsets were also touted as a feature.

Mac OS X 10.4 Tiger had a bunch of new iChat features, as well as a new icon of a blue speech bubble with camera icon. It allowed videoconferencing using the new h.264 codec, which gave a much clearer image, with up to 4 participants (as long as one of them had a fast enough computer) or voice chat with up to 10 users. It also featured Jabber support and allowed encrypted IMs using SSL certificates on a .Mac account or Tiger server. The Jabber support also allowed the use of Google Talk. iChat also allowed the use of USB webcams in 10.4.9.

Mac OS X 10.5 Leopard has a new list of features, such as special visual effects like those in Apple's Photo Booth application, as well as the ability to change the background of the video as a backdrop. It also promised tabbed browsing, video session recording, the ability to set your online status to invisible, the the ability to log into multiple AIM/.Mac accounts at once, live animated user icons, sharing slideshows, presentations, and movies over video chats, and screen sharing using OS X's VNC capabilities.