If you are in a course that will be holding sessions in Blackboard Collaborate, below are the system and browser for desktop computers.

Windows XP is not listed due to End of Life support by UTA at the end of Fall 2013 and Microsoft in April of 2014.
Mac OS X 10.9 (Mavericks) has not been released, so testing has not been done.

Windows Vista:
Supported Web browsers: IE8, IE9, Mozilla Firefox & Google Chrome
supported Java Versions: V1.7, V1.7 (Java SE6 & 7)

Windows 7:
Supported Web Browsers: IE8, IE9, IE10 (supported but not tested), Mozilla Firefox & Google Chrome
Supported Java Versions: V1.7, V1.7 (Java SE6 & 7)

Windows 8:
Supported Web Browsers: IE10, Mozilla Firefox, Google Chrome
Supported Java Versions: V1.7, V1.7 (Java SE6 & 7)

Mac OS X 10.6 (Snow Leopard):
Supported Web Browsers: Safari 4.0, 5.0, 5.1, Mozilla Firefox, Google Chrome
Supported Java Versions: Apple java 1.5.0_16 +(J2SE5-32 Bit), Apple Java 1.6.0_07 +(J2SE6-64 Bit), Oracle Java 1.7

Mac OS X 10.7 (Lion)
Supported Web Browsers: Safari 6.0 & Mozilla Firefox
Supported Java Versions: Apple java 1.5.0_16 +(J2SE5-32 Bit), Apple Java 1.6.0_07 +(J2SE6-64 Bit), Oracle Java 1.7

Mac OS X 10.8 (Mountain Lion)
Supported Web Browsers: Safari 6.0 & Mozilla Firefox
Supported Java Versions: Apple java 1.5.0_16 +(J2SE5-32 Bit), Apple Java 1.6.0_07 +(J2SE6-64 Bit), Oracle Java 1.7

Linux/Ubuntu:
Supported Web Browsers: Mozilla Firefox
Supported Java Versions: V1.7, V1.7 (Java SE6 & 7)

It is Highly Recommended that you have a Broadband Internet Connection when accessing a Collaborate Session

Recommended: Always test your system before attempting to enter a Collaborate session. Install all recommended software and run all system updates prior to entering a session.